Medtronic DDPA2D4 Reference Guide

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

Family of MR Conditional digital implantable cardioverter defibrillators with cardiac resynchronization therapy, SureScan™ technology, and Bluetooth® wireless telemetry

Reference Manual Caution: Federal law (USA) restricts this device to sale by or on the order of a physician.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

Reference Manual

A reference manual for the Medtronic Cobalt XT HF, Cobalt HF, and Crome HF CRT-D MRI SureScan families of digital implantable cardioverter defibrillators with cardiac resynchronization therapy, SureScan technology, and Bluetooth wireless telemetry.

Medtronic, Medtronic with rising man logo, and Medtronic logo are trademarks of Medtronic. Third-party trademarks (“TM*”) belong to their respective owners. The following list includes trademarks or registered trademarks of a Medtronic entity in the United States and/or in other countries.

Active Can™, AdaptivCRT™, ATP During Charging™, Capture Management™, Cardiac Compass™, CareAlert™, CareLink™, ChargeSaver™, Cobalt™, Crome™, EffectivCRT™, Intrinsic ATP™, Marquis™, Medtronic CareAlert™, Medtronic CareLink™, MVP™, OptiVol™, PR Logic™, Quick Look™, Reactive ATP™, SmartShock™, SureScan™, Switchback™, T-Shock™, VectorExpress™

Medtronic

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

Contents

1 Introduction ............................................................ 8

1.1 About the product literature .......................................... 8

1.2 Device features per model .......................................... 9

2 Patient follow-up guidelines ............................................ 11

2.1 In-clinic follow-up appointments and remote monitoring ................ 11

2.2 Suspending and resuming tachyarrhythmia detection .................. 17

2.3 Optimizing device longevity ........................................ 18

3 Diagnostic data features ............................................... 23

3.1 Quick Look summary data ......................................... 23

3.2 Medtronic CareAlert Monitoring ..................................... 25

3.3 OptiVol 2.0 Fluid Status Monitoring .................................. 33

3.4 RV Lead Integrity Alert ............................................. 37

3.5 Cardiac Compass Trends .......................................... 41

3.6 Heart Failure Management Report .................................. 47

3.7 Arrhythmia Episodes data .......................................... 49

3.8 Episode and therapy counters ...................................... 54

3.9 Flashback data ................................................... 57

3.10 Ventricular sensing episodes ....................................... 58

3.11 Rate Drop Response episodes ..................................... 59

3.12 EffectivCRT Episodes ............................................. 60

3.13 MVP mode switches data .......................................... 61

3.14 Rate Histograms ................................................. 61

3.15 Device and lead performance data .................................. 63

3.16 Automatic device status monitoring .................................. 68

3.17 EffectivCRT Diagnostic ............................................ 70

4 Pacing features ....................................................... 73

4.1 Sensing ......................................................... 73

4.2 Basic pacing ..................................................... 83

4.3 Managed Ventricular Pacing (MVP) .................................. 94

4.4 CRT pacing ..................................................... 101

4.5 AdaptivCRT ..................................................... 110

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4.6 Multiple point pacing (MPP) ....................................... 115

4.7 Rate Response .................................................. 117

4.8 Capture Management ............................................ 122

4.9 Rate Adaptive AV ................................................ 136

4.10 Auto PVARP .................................................... 138

4.11 Rate Drop Response ............................................. 140

4.12 Sleep feature ................................................... 145

4.13 Non-Competitive Atrial Pacing ..................................... 147

4.14 PMT Intervention ................................................ 149

4.15 PVC Response .................................................. 151

4.16 Ventricular Safety Pacing ......................................... 152

4.17 Mode Switch .................................................... 155

4.18 Atrial Tracking Recovery .......................................... 157

4.19 Ventricular Sense Response ...................................... 159

4.20 Conducted AF Response ......................................... 162

4.21 EffectivCRT During AF ........................................... 164

4.22 Atrial Rate Stabilization ........................................... 167

4.23 Atrial Preference Pacing .......................................... 170

4.24 Post-Mode Switch Overdrive Pacing ................................ 174

4.25 Post Shock Pacing ............................................... 177

4.26 Post VT/VF Shock Overdrive Pacing ................................ 178

4.27 Ventricular Rate Stabilization ...................................... 179

5 Tachyarrhythmia detection features .................................... 182

5.1 AT/AF detection ................................................. 182

5.2 VT/VF detection ................................................. 187

5.3 PR Logic ....................................................... 201

5.4 Wavelet ........................................................ 204

5.5 Onset .......................................................... 211

5.6 Stability ........................................................ 215

5.7 High Rate Timeout ............................................... 217

5.8 TWave Discrimination ............................................ 218

5.9 RV Lead Noise Discrimination ..................................... 221

6 Tachyarrhythmia therapy features ..................................... 226

6.1 Atrial therapy scheduling .......................................... 226

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6.2 Atrial ATP therapies .............................................. 232

6.3 Atrial cardioversion ............................................... 243

6.4 VF therapies .................................................... 249

6.5 Ventricular ATP therapies ......................................... 259

6.6 Ventricular cardioversion .......................................... 269

6.7 Progressive Episode Therapies .................................... 278

Glossary ................................................................ 280

Index ................................................................... 290

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1 Introduction

1.1 About the product literature

This manual describes the operation and intended use of features offered by Medtronic Cobalt XT HF, Cobalt HF, and Crome HF CRT-D MRI SureScan devices.

Throughout this manual, the word “device” refers to the implanted cardioverter defibrillator.

Unless otherwise noted, all device features described in this manual apply to Cobalt XT HF Quad devices. To determine which features are available for another model in the Cobalt XT HF, Cobalt XT HF Quad, Crome HF, and Crome HF Quad CRT-D MRI SureScan families, refer to Section 1.2, Device features per model, page 9.

1.1.1 Product literature

Before implanting the device, it is recommended that you take the following actions:

• Read the product literature for information about prescribing, implanting, and using the device and conducting a patient follow-up session.

• Thoroughly read the technical manuals for the leads used with the device. Also read the technical manuals for other system components.

• Discuss the device and implant procedure with the patient and any other interested parties, and give them any patient information materials packaged with the device.

Additional information about the device is provided in the following documents:

MRI technical manual – This manual provides MRI-specific procedures and warnings and precautions.

Implantable device app help – The help explains how to use the implantable device app to program the device settings and view the stored device data.

Device manual – This manual contains model-specific feature information, indications and contraindications, warnings and precautions, instructions for implanting the device, quick reference specifications, and parameter tables.

Explanation of symbols – This document defines the symbols that may appear on the device package. Refer to the package label to see which symbols apply specifically to this device.

Medical Procedure and EMI Warnings, Precautions, and Guidance Manual for Health Care Professionals – This manual provides warnings, precautions, and guidance for health

care professionals who perform medical therapies and diagnostic procedures on cardiac device patients. This manual also includes information about hazards from sources of

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electromagnetic interference (EMI) in the patient’s home, recreational environments, and occupational environments.

Radio regulatory compliance insert – This document provides compliance information related to the radio components of the device.

1.1.2 Technical support

Medtronic employs highly trained representatives and engineers located throughout the world to serve you and, upon request, to provide training to qualified hospital personnel in the use of Medtronic products.

In addition, Medtronic maintains a professional staff of consultants to provide technical consultation to product users.

For more information, contact your local Medtronic representative or call or write Medtronic at the appropriate telephone number or address listed on the back cover.

1.2 Device features per model

The following table lists the features in the Cobalt XT HF, Cobalt HF and Crome HF CRT-D MRI SureScan device families that are not available in all devices. Features that are omitted from this list apply to every device in the portfolio.

Table 1. Device model features

Cobalt XT HF, Cobalt HF, and Crome HF CRT-D MRI

SureScan

DTPA2QQ DTPA2Q1

AdaptivCRT algorithm

EffectivCRT Diagnostic

EffectivCRT During AF algorithm

MPP X — X — X —

SmartShock 2.0 technology

X X X X — —

X X — — — —

— — X X X X

DTPA2D1 DTPA2D4

DTPB2QQ DTPB2Q1

DTPB2D1 DTPB2D4

DTPC2QQ DTPC2Q1

DTPC2D4 DTPC2D1

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Table 1. Device model features (continued)

Cobalt XT HF, Cobalt HF, and Crome HF CRT-D MRI

SureScan

DTPA2QQ DTPA2Q1

SmartShock 2.0+ technology with Intrinsic ATP algo-

rithm

VectorExpress 2.0 X — X — X —

Includes the following features: Confirmation+, PR Logic, RV Lead Integrity Alert, RV Lead

X X — — — —

DTPA2D1 DTPA2D4

DTPB2QQ DTPB2Q1

DTPB2D1 DTPB2D4

DTPC2QQ DTPC2Q1

DTPC2D4 DTPC2D1

Noise Discrimination and alert, SVT Discriminators in VF Zone, TWave Discrimination, and Wavelet

Includes the following features: Confirmation+, Intrinsic ATP (iATP) algorithm, PR Logic + Wavelet, RV Lead Integrity Alert, RV Lead Noise Discrimination and alert, SVT Discriminators in VF Zone, TWave Discrimination

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2 Patient follow-up guidelines

2.1 In-clinic follow-up appointments and remote monitoring

Schedule regular in-clinic follow-up appointments with the patient throughout the service life of the device. For patients enrolled in the Medtronic CareLink Network, remote monitoring can replace the need for some in-clinic follow-up appointments. With remote monitoring, data from a patient’s implanted device is sent to the Medtronic CareLink Network, and you can review the transmitted data on the Medtronic CareLink Network website. Schedule in-clinic follow-up appointments and CareLink transmissions as follows:

• Schedule an in-clinic follow-up appointment within 72 hours of implant so that the patient can be checked for lead dislodgment, wound healing, and postoperative complications.

• Schedule an in-clinic follow-up appointment within 2 to 12 weeks after implant to evaluate the condition of the patient, the device, and the leads, and to verify that the device is configured appropriately for the patient.

• Schedule routine CareLink transmissions or in-clinic follow-up appointments every 3 to 6 months with in-clinic follow-up appointments occurring at least annually.

• When the device battery approaches Recommended Replacement Time (RRT), schedule CareLink transmissions or in-clinic follow-up appointments every 1 to 3 months.

• Schedule in-clinic follow-up appointments as needed (for example, if data from a CareLink transmission indicates that the patient’s device requires adjustment).

2.1.1 Remote monitoring options

The device provides automatic wireless remote monitoring, if available, through a patient-owned smart phone or tablet running a mobile app (referred to as the patient app) or through a home communicator. This device features Bluetooth® wireless technology1. Routine monitoring transmissions occur according to a schedule that you create on the Medtronic CareLink Network website. In addition, the CareAlert Monitoring feature provides automatic, unscheduled transmissions for specific clinical or device status events (see Section 3.2, Medtronic CareAlert Monitoring, page 25). Patients can also send unscheduled transmissions.

The Bluetooth® word mark is a registered trademark of Bluetooth SIG, Inc. and any use of this mark by Medtronic is under license.

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Note: When viewing a CareLink transmission, the data collected since the last session is presented differently than it is for a patient session. For a CareLink transmission, the last session is defined as either the last patient session or the last CareLink transmission. During an in-clinic appointment, the last session is defined as the last patient session.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.1.2 Follow-up process

The process for conducting a follow-up evaluation, either during an in-clinic appointment or with a CareLink transmission, includes the following steps:

1. Review the patient’s presenting rhythm.

2. Verify the status of the implanted system.

3. Verify the clinical effectiveness of the implanted system.

4. During an in-clinic follow-up appointment, adjust device parameters as necessary.

5. If evaluating data remotely, schedule an in-clinic follow-up appointment as necessary.

2.1.3 Reviewing the presenting rhythm

The presenting rhythm may indicate the presence of undersensing, far-field oversensing, or loss of capture. The presence of these basic pacing issues can affect the delivery of therapy. These issues can often be resolved by making basic programming changes.

Review the presenting rhythm as follows:

• During an in-clinic follow-up appointment, view the Live Rhythm Monitor and record the EGM and marker traces.

• For remote monitoring, review the EGM data that was recorded at the time of the CareLink transmission.

Viewing this information can help you identify any issues with the patient’s presenting rhythm. It may be necessary to adjust the pacing parameters.

2.1.4 Verifying the status of the implanted system

To verify the status of the implanted system, perform the following tasks:

• Assess the battery status.

• Check lead measurements and trend data.

• Review any Quick Look observations about the device and lead status.

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2.1.4.1 Assessing the battery status

To assess the status of the device battery, review the REMAINING LONGEVITY estimate on the Quick Look screen. If the device battery has reached a replacement threshold, the associated indicator is displayed.

To see more detail about the battery status, including battery voltage, tap REMAINING LONGEVITY on the Quick Look screen to see the device data provided by the BATTERY AND LEAD MEASUREMENTS window.

Warning: Replace the device immediately if the End of Service (EOS) indicator is displayed. The device may lose the ability to pace, sense, and deliver therapy adequately after the battery reaches End of Service.

If the Recommended Replacement Time (RRT) indicator or the Elective Replacement Indicator (ERI) is displayed, or if the battery voltage is at or below the displayed RRT voltage, contact your Medtronic representative and schedule a replacement procedure with your patient. For more information about the replacement indicators, see Section 3.15, Device and lead performance data, page 63.

2.1.4.2 Checking lead measurements and trend data

In-clinic follow-up appointment – During an in-clinic follow-up appointment, you can

check the status of the implanted leads. On the Quick Look screen you can review up to 12 months of the following lead trend data:

• Lead impedance

– Pacing (Ω)

– Defib (Ω)

• THRESHOLD (V @ ms)—shows P-wave and R-wave threshold trends

• AMPLITUDE (mV)—shows capture amplitude trends

For a more detailed history of each trend, tap LEAD TRENDS. For more information about the automatic collection of these trends, see Section 3.15,

Device and lead performance data, page 63. To gather real-time information about the performance of the device and leads, perform the

following tests:

• LEAD IMPEDANCE

• PACING THRESHOLD

• SENSING

• VectorExpress

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For more information about these tests, refer to the implantable device app help.

Evaluating a CareLink transmission – When evaluating a CareLink transmission, you can check the status of implanted leads by reviewing the most recent lead impedance, capture threshold, and sensing amplitude measurements on the Quick Look report. Compare these values to the patient history and to the trend data provided on the Lead Trends reports.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.1.4.3 Reviewing Quick Look observations about the status of the device, the leads, and the alert events

The Quick Look data includes observations that are based on an analysis of the programmed parameters and the collected data. Observations may include information about the status of the device and the battery and the integrity of the implanted leads or potential issues with the programmed parameter settings. If Medtronic CareAlert Monitoring is enabled, any alert events detected by the device are presented in the OBSERVATIONS section of the Quick Look screen. Review these observations and check related reports for evidence of a problem with the device or the leads.

2.1.5 Verifying the clinical effectiveness of the implanted system

You can use the information available on the Quick Look screen and the saved reports to assess whether the device is providing adequate clinical support for the patient.

2.1.5.1 Reviewing Quick Look observations about clinical status

The Quick Look data includes observations about noteworthy or abnormal patient conditions such as low patient activity, unexpectedly high rates, or high arrhythmia burden. If you enable Medtronic CareAlert Monitoring, the OBSERVATIONS section of the Quick Look screen lists alert events detected by the device. To evaluate the clinical effectiveness of the implanted system, review this event data and check the related data.

2.1.5.2 Assessing the effectiveness of pacing therapy

1. Review the pacing percentages in the Quick Look data. To assess the patient’s pacing and sensing history in more detail, review the rate histograms data. For more information, see Section 3.14, Rate Histograms, page 61.

2. Review Cardiac Compass Trends data and compare it with the patient history. Cardiac Compass Trends data can help you to determine whether changes in the patient’s activity, pacing therapies, and arrhythmias have occurred during the past 14 months. For more information about the data collected by the Cardiac Compass feature, see Section 3.5, Cardiac Compass Trends, page 41.

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3. Evaluate the patient’s pacing thresholds by reviewing capture threshold trend data. During an in-clinic follow-up appointment, you can also perform a Pacing Threshold Test. For devices that support quadripolar LV leads, you can use the VectorExpress LV Automated Test to evaluate the patient’s LV capture thresholds across all LV pacing vectors. Refer to the implantable device app help for more information about conducting these tests.

4. Check the programmed pacing parameters to confirm that they provide an appropriate safety margin.

5. During in-clinic follow-up appointments, interview the patient to confirm that the patient is receiving adequate cardiac support for activities of daily living.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.1.5.3 Assessing effective cardiac resynchronization therapy

1. Review the Quick Look observations related to ventricular pacing percentage, effective ventricular pacing percentage (for devices that have the EffectivCRT Diagnostic feature), or ventricular sensing episodes.

2. Check the stored ventricular sensing episodes to determine the continuity of CRT pacing. For more information, see Section 3.10, Ventricular sensing episodes, page 58.

3. Review the rate histograms for more information on atrial and ventricular pacing, in general, and ventricular rates during AT/AF episodes.

4. Review Cardiac Compass Trends data for comparison to patient history. For more information, see Section 3.5, Cardiac Compass Trends, page 41.

If CRT has not been continuously delivered, consider the following programming options:

• Perform basic programming changes to increase the Upper Tracking Rate or decrease the total atrial refractory period. For more information about the total atrial refractory period, see Section 4.1, Sensing, page 73.

• Enable V. Sense Response, Atrial Tracking Recovery, Conducted AF Response, or EffectivCRT During AF to promote more continuous delivery of CRT.

2.1.5.4 Assessing tachyarrhythmia detection

1. Review the Quick Look data for the counts of each kind of tachyarrhythmia episode.

2. Review the Cardiac Compass Trends data and the Rate Histograms data to assess the frequency of arrhythmias and device therapies in consideration of patient condition. For more information, see Section 3.5, Cardiac Compass Trends, page 41 and Section 3.14, Rate Histograms, page 61.

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Episode misidentification – If the episode records indicate that the device has misidentified the patient’s rhythm, carefully review the tachyarrhythmia episode and sensing integrity data, the Cardiac Compass Trends data, and the data stored for other episodes. Consider adjusting the detection parameters and the SVT detection criteria as needed. For more information about how to view sensing integrity data, see Section 4.1, Sensing, page 73.

Caution: Use caution when reprogramming the detection or sensing parameters to ensure that changes do not adversely affect VF detection. Ensure that appropriate sensing is maintained. For more information, see Section 4.1, Sensing, page 73.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.1.5.5 Assessing tachyarrhythmia therapy

1. Review any Medtronic CareAlert notifications in the Quick Look OBSERVATIONS section that relate to therapy delivery. To see detailed information about Medtronic CareAlert notifications, tap DATA > CareAlert EVENTS from the Menu button.

2. Check tachyarrhythmia episode records to determine the effectiveness of therapies that have been delivered.

3. Adjust the therapy parameters as needed.

2.1.6 Adjusting device parameters

Adjust the pacing, tachyarrhythmia detection, tachyarrhythmia therapy, and diagnostic data parameters as needed to address any issues identified during the follow-up appointment.

Caution: Use caution when reprogramming the detection or sensing parameters to ensure that appropriate sensing is maintained. For more information, see Section 4.1, Sensing, page 73 .

2.1.7 Scheduling an in-clinic follow-up appointment

Data transmitted to the Medtronic CareLink Network may indicate the need to schedule an in-clinic follow-up appointment with your patient in addition to the patient’s regularly scheduled appointments. You may need to perform manual tests, adjust device parameters, or assess lead status more directly. The following table shows an example of how data from a CareLink transmission may be used to make scheduling decisions.

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Table 2. Example: Responses to different kinds of CareLink transmissions

Device and lead status

Normal Normal According to the regular schedule

Normal Abnormal, but no urgent or emer-

Normal Abnormal, urgent condition Within 1 week

Normal Abnormal, emergency condition Immediately

Abnormal Any Immediately

Clinical status

gency conditions

When to schedule an in-clinic follow-up appointment

According to the regular schedule

2.2 Suspending and resuming tachyarrhythmia detection

It may be necessary to turn off tachyarrhythmia detection in some situations. For example, during emergency therapies and some EP study tests, therapies are delivered manually, and detection and episode storage are not needed. Also, certain types of surgery, including electrocautery surgery, RF ablation, and lithotripsy, can cause the device to detect tachyarrhythmias inappropriately and possibly deliver inappropriate therapy.

When detection is suspended, the device temporarily stops the process of classifying intervals for tachyarrhythmia detection. Sensing and bradycardia pacing remain active, and the programmed detection settings are not modified. When the device resumes detection, it does so at the previously programmed detection settings. The suspend and resume functions apply to both atrial and ventricular tachyarrhythmia detection.

Note: If the MRI SureScan feature is programmed to On, tachyarrhythmia detection and the Medtronic CareAlert feature (including audible alerts) are suspended.

2.2.1 Considerations for suspending detection

If you suspend detection during a tachyarrhythmia detection process but before detection has occurred, the initial detection never occurs. When you resume, detection starts over.

If you suspend detection after a tachyarrhythmia detection has occurred and resume detection before the tachyarrhythmia episode terminates, redetection works differently for each type of episode, as follows:

AT/AF episodes – If you suspend detection during a detected AT/AF episode and then resume detection before the episode terminates, detection starts over for the same episode.

Note: Suspending tachyarrhythmia detection does not affect the Mode Switch feature. A mode switch may occur whether or not tachyarrhythmia detection has been suspended.

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VT/FVT/VF episodes – If you suspend detection while a therapy is being delivered, the device finishes delivering the therapy that is in progress but does not redetect until you resume detection. If you resume detection before the episode terminates, the device begins redetection, and the episode is redetected if the programmed Beats to Redetect value is reached.

VT Monitor episodes – If you suspend detection during a detected VT Monitor episode, and then resume detection before the episode terminates, there will be episode data storage for 2 episodes with the first episode terminated while the rate is still fast.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.2.2 How to suspend or resume detection with the implantable device app

The SUSPEND and RESUME buttons at the top of the screen can be used when there is telemetry with the device and the device software is running.

1. To suspend detection, tap SUSPEND. The implantable device app displays the annotation SUSPENDED.

2. To resume detection, tap RESUME.

2.2.3 How to suspend or resume detection with a magnet

1. To suspend detection, place the magnet (such as the Model 9466 Tachy Patient Magnet) over the device.

2. To resume detection, remove the magnet from over the device.

2.3 Optimizing device longevity

Optimizing device longevity is a desirable goal because it can reduce the frequency of device replacement for patients. Optimizing device longevity requires balancing the benefit of device therapy and diagnostic features with the energy requirements placed on the battery as a result of these features.

To view the REMAINING LONGEVITY estimate for the device, refer to the Quick Look screen.

Note: The remaining longevity estimate is updated when parameters are reprogrammed and when the device is interrogated.

The following sections describe strategies that can help reduce the energy requirements placed on the battery.

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2.3.1 Promoting intrinsic AV conduction

MVP (Managed Ventricular Pacing) – For non-CRT pacing, the MVP feature promotes AV

conduction by reducing unnecessary right ventricular pacing. The primary benefit of the MVP feature is therapeutic, but it may also preserve device longevity as a result of a decrease in the percentage of pacing. For more information, see Section 4.3, Managed Ventricular Pacing (MVP), page 94.

Promoting AV conduction with longer AV intervals – Another method of promoting AV conduction is to increase the paced AV interval and the sensed AV interval. This action allows intrinsic conduction to occur before a ventricular pace. Fewer pacing pulses may help to preserve device longevity. For more information, see Section 4.2, Basic pacing, page 83.

2.3.2 Managing pacing outputs

Capture Management – The Capture Management feature provides the device with

automatic monitoring and follow-up capabilities for managing pacing thresholds. This feature is designed to monitor the pacing threshold and, optionally, to adjust the pacing outputs to maintain capture. Programming the Capture Management feature allows the device to set the pacing amplitude just high enough to maintain capture while preserving battery energy. For more information, see Section 4.8, Capture Management, page 122 .

Manual optimization of amplitude and pulse width – If you choose to program the Capture Management feature to Off, you can optimize the patient’s pacing output parameters manually. Perform a Pacing Threshold Test to determine the patient’s pacing thresholds. Select amplitude and pulse width settings that provide an adequate safety margin above the patient’s pacing threshold. These actions decrease the pacing outputs and preserve battery energy. Refer to the implantable device app help for more information about performing a Pacing Threshold Test.

Pacing rate – The more paced events that are delivered, the more device longevity is reduced. Make sure that you have not programmed an unnecessarily high pacing rate for the patient. Carefully consider using features that increase the bradycardia pacing rate. Use features such as Atrial Preference Pacing (APP), Conducted AF Response, and Rate Response only for patients who can receive therapeutic benefit from the feature.

Auto LV safety margin – For LV Capture Management, programming the Amplitude Safety Margin to + Auto enables the device to monitor the stability of the pacing thresholds and then optimize the LV pacing amplitude safety margin automatically. The feature sets the safety margin just high enough above the pacing amplitude to maintain capture while preserving battery energy.

Multiple point pacing (MPP) – Multiple point pacing is available in some devices that support a quadripolar LV pacing lead. It allows the device to deliver a second, separately

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programmed LV pacing pulse during CRT pacing. It is not recommended to use multiple point pacing unless there is evidence that the patient is not responding to single site LV pacing (for example, patient symptoms, quality of life, NYHA classification, electrocardiographic and/or echocardiographic evidence based on clinical judgment). Long-term use of multiple point pacing affects device longevity (18% median longevity reduction). There is no randomized clinical trial data for this device that demonstrates that programming MPP has a positive impact on LV pacing response.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.3.3 Optimizing tachyarrhythmia therapy settings

Defibrillation – To treat ventricular fibrillation episodes, the device may deliver defibrillation

therapy to terminate the episode and restore the patient’s normal sinus rhythm. The device can be programmed to deliver a sequence of up to 6 defibrillation therapies. Although defibrillation therapy expends a high level of energy, VF therapies should be programmed to the maximum energy level.

Atrial cardioversion – You can program the device to deliver automatic atrial cardioversion (CV) therapies to treat atrial tachyarrhythmia episodes. If you choose to treat the patient with atrial CV therapies, you can extend device longevity by carefully considering how you program the following parameters: the number of shocks delivered during a 24-hour cycle and the Episode Duration before CV. It is recommended that CV therapy be set to full energy to terminate the arrhythmia. For more information, see Section 6.3, Atrial cardioversion, page 243.

Ventricular cardioversion – If you are providing ventricular cardioversion therapies for the patient, consider programming the therapy energy to a value lower than the maximum energy but high enough to terminate the VT. However, at least one VT therapy and one FVT therapy in a sequence should be programmed to the maximum energy level. For more information, see Section 6.6, Ventricular cardioversion, page 269.

FVT via VF detection – An FVT detection zone can be used to detect and treat a VT episode that is in the rate zone for VF. This approach can help maintain reliable detection of VF while allowing ATP to be delivered for fast VT episodes. For more information, see Section 5.2, VT/ VF detection, page 187.

Antitachycardia pacing (ATP) – ATP therapies interrupt the tachycardia episode and restore the patient’s normal sinus rhythm. ATP therapies deliver pacing pulses instead of the high-voltage shocks that are delivered in cardioversion therapy and defibrillation.

ATP therapy requires less battery energy than cardioversion or defibrillation. For some patients, you may be able to program the device to deliver ATP therapies before delivering high-voltage therapies.

For more information about ATP and atrial episodes, see Section 6.2, Atrial ATP therapies,

page 232. For more information about ATP and ventricular episodes, see Section 6.5, Ventricular ATP therapies, page 259.

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Delivering ATP before the first defibrillation – You can program the device to deliver ATP as the first defibrillation therapy before the device is charged. This action can prevent delivery of high-voltage therapy for rhythms that can be terminated by ATP (rapid, monomorphic VT, for example).

If you program the ChargeSaver feature to On, the device can also automatically switch to the ATP Before Charging operation. This switch allows the device to attempt a sequence of ATP therapy before charging the capacitors to treat a detected VF episode. For more information, see Section 6.4, VF therapies, page 249.

Cobalt™ XT HF / Cobalt™ HF / Crome™ HF CRT-D MRI SureScan™

2.3.4 Disabling Atrial Sensitivity

Atrial Sensitivity – When an atrial lead is not present or when atrial monitoring is not

needed due to chronic AT/AF, consider programming Atrial Sensitivity to Off before changing the mode to VVI or VVIR to preserve battery energy.

Note: When Atrial Sensitivity is programmed to Off, AT/AF monitoring and PR Logic are disabled.

2.3.5 Considering how diagnostic features with data storage impact longevity

Pre-arrhythmia EGM storage – When the device is set to nominal parameters, it provides

continuous Pre-arrhythmia EGM storage with minimal longevity impact. If the parameters for EGM storage or sense polarity are changed, the device may be required to keep additional EGM circuitry enabled at all times, which reduces device longevity. You can preserve longevity by ensuring that the stored EGM channels use EGM SOURCE values that match the Sense Polarity values.

If it is necessary to store EGM from a source that does not match the sense polarity, consider the following information about the Pre-arrhythmia EGM feature:

• The Pre-arrhythmia EGM feature allows the device to collect up to 20 s of EGM data before the onset of VT/VF, VT Monitor, SVT, VT-NS, and Fast A&V episodes.

• The Pre-arrhythmia EGM feature does not apply to AT/AF episodes. The device stores approximately 4 s of EGM before AT/AF detection, regardless of the Pre-arrhythmia EGM storage setting.

• When Pre-arrhythmia EGM storage is set to Off, the device begins to store EGM information for VT/VF, VT Monitor, and SVT episodes after the third tachyarrhythmia event occurs. Though EGM is not recorded before the start of the arrhythmia, the device still records up to 20 s of data before the onset or the detection of the episode. This data includes interval measurements and markers. In addition, Flashback data is stored for the most recent tachyarrhythmia episodes.

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• For a patient with uniform tachyarrhythmia onset mechanisms, the greatest benefit of Pre-arrhythmia EGM storage is obtained after capturing a few episodes. Program Pre-arrhythmia EGM to Off after you have obtained the data of interest.

Holter telemetry – Extended use of the Holter telemetry feature decreases device longevity. The Holter telemetry feature continues to transmit EGM and marker data for the programmed time duration, regardless of whether the patient connector is positioned over the device.

Medtronic CareLink remote transmissions – When scheduling Medtronic CareLink remote transmissions, be aware that increasing the frequency of remote transmissions reduces the service life of the implanted device. Refer to the device manual for more information about the estimated effect on a specific device model. To conserve battery energy, schedule the lowest frequency of remote transmissions that still allows for the desired monitoring of your patient’s device.

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2.3.6 Extended wireless telemetry session

If the implantable device app detects no activity for 45 min, a pop-up window prompts you to extend the session. If you do not tap EXTEND to extend the session, the patient session ends in 15 min.

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3 Diagnostic data features

3.1 Quick Look summary data

At the start of a patient session, it is useful to quickly view summary information about device operation and the patient’s condition. This overview can help you to determine whether you need to look more closely at diagnostic data or reprogram the device to optimize therapy for the patient.

The Quick Look data summarizes the most important indicators of system operation and the patient’s condition. These indicators include device and lead status data, pacing therapy information, arrhythmia episode data, and system-defined observations.

You can view Quick Look data on the Quick Look screen, which is displayed at the beginning of a patient session. To return to the Quick Look screen from another screen, tap Quick Look from the Menu button. For more information about using the Quick Look screen, refer to the implantable device app help.

Note: The Quick Look screen shows information collected since the last patient session and stored in device memory. Programming changes made during the current session can affect the Quick Look observations.

3.1.1 Quick Look device and lead status information

The Quick Look data includes the following information about device and lead status:

• Estimate of remaining battery longevity

• Trends of the weekly average impedance, capture threshold, and wave amplitude measurements

• Most recent measured values for impedance, capture threshold, and wave amplitude

3.1.2 Quick Look pacing therapy information

The Quick Look data includes the following information about pacing therapy, listed under the % OF TIME label:

• Percentage of time in atrial pacing (AP) and ventricular pacing (VP) since the last patient session

• Percentage of time pacing in AS-VP event sequences

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• For devices with the EffectivCRT Diagnostic feature, the percentage of time in effective CRT pacing (Effective) since the last patient session

• An indicator that the pacing mode is currently programmed to an MVP mode (MVP On) or to another pacing mode (MVP Off)

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3.1.2.1 Quick Look arrhythmia episode information

The Quick Look data includes the following information about arrhythmia episodes since the last patient session:

• Percentage of time spent in AT/AF

• Number of VT/VF episodes treated with tachyarrhythmia therapy

• Number of AT/AF episodes treated with tachyarrhythmia therapy

• Number of delivered shocks

• Number of monitored VT episodes

• Number of monitored SVT episodes

• Number of monitored AT/AF episodes

3.1.2.2 Quick Look observations

Observations are based on an analysis of programmed parameters and data collected since the last session. The following types of observations may occur:

• Device status observations inform you of conditions that affect device operation and require attention. Examples of such conditions include Recommended Replacement Time (RRT) or the occurrence of a device reset.

• Lead status observations report any potential issues with the sensing integrity of the leads, possible lead dislodgments, and abnormal Capture Management results. You may also be warned about possible inconsistencies in the programming of lead polarity.

• Parameter observations warn of any inconsistencies in the programming of detection and therapy parameters. An example is certain parameter settings resulting in a therapy being disabled.

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• Diagnostic data observations report noteworthy arrhythmia episodes. Examples include arrhythmias of different types occurring together and episodes for which therapies were unsuccessful. Conditions that prevent diagnostic data from being collected effectively are also reported.

• Medtronic CareAlert observations can report system or device performance conditions and certain heart rhythm conditions. For more information, see Section 3.2, Medtronic CareAlert Monitoring, page 25.

• Clinical status observations alert you to abnormal patient conditions, such as low activity rates, unexpectedly high heart rates, high arrhythmia burden, fluid accumulation, or ineffective CRT pacing.

If you tap an observation that includes additional details, a > button appears at the end of the OBSERVATIONS field. To see the observation details, tap the > button.

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3.2 Medtronic CareAlert Monitoring

Important clinical management and system performance events can occur between scheduled patient sessions. These events can relate to clinical management data, to inappropriately programmed settings, or to system performance issues that must be investigated. The early detection and notification of these events, if they occur, enable you to intervene promptly with appropriate care for your patient.

The device continuously monitors for a specified set of clinical management and system performance events that can occur between scheduled follow-up sessions. If the device detects that such an event has occurred and if alerting parameters are programmed to On, Medtronic CareAlert Monitoring responds in the following ways:

• Patient alert

• Wireless signal and network transmission of event information

Medtronic CareAlert Monitoring continuously monitors for alert events. If an event occurs, CareAlert Monitoring sends alert data about specified clinical management or system performance events to the Medtronic CareLink Network (if available). Alert data is sent through the patient’s personal wireless device or through a Medtronic home communicator.

• Notification of alert event

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Depending on the severity of the alert condition, you can set up Medtronic CareAlert notifications through the CareLink Network (if available). You can hold the alert for routine review on the CareLink website, or you can be notified by the following notification methods, according to your preferences:

– Email

– Text message

– Pager

– Automated voice message

– Telephone call

Note: CareAlert notification methods, when available, vary from geography to geography.

3.2.1 Operation of Medtronic CareAlert Monitoring

If a clinical event or a system performance event occurs, and the device is programmed to notify you over the CareLink Network, the CareAlert Monitoring feature transmits alert data from the device to the patient app or the home communicator. The patient app or the home communicator then sends the alert data to the CareLink Network. The CareLink Network records the alert, then notifies you according to your preferences.

If an alert data transmission from the device is unsuccessful, the CareAlert Monitoring feature tries to establish communication with the patient app or the home communicator every 3 hours until the data transmission is successful. If the alert data remains untransmitted for 72 hours, the device emits a tone at the Alert Time that you select for your patient or at intervals unique to some alerts as described in Section 3.2.3.1 and Section 3.2.3.2.

Note: After a wireless alert signal is successfully transmitted, the device does not retransmit data for that alert until the alert is cleared. There are 2 exceptions to this rule: a device reset alert is transmitted each time a device reset occurs, and an OptiVol Event alert is transmitted each time the patient’s fluid level exceeds the OptiVol Threshold following a reset of the OptiVol 2.0 Fluid Index (see Section 3.3, OptiVol 2.0 Fluid Status Monitoring, page 33).

The CareAlert notification methods (any one or a combination of voice message, text message, pager, email, live call, or website-only) can be programmed to On or Off, on a per-patient and per-clinic basis, and according to time of day.

CareAlert notification methods, when available, vary from geography to geography.

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3.2.2 Operation of Medtronic CareAlert events

Medtronic CareAlert events are either programmable or always on:

• Clinician-defined alerts can be programmed on or off.

• System-defined alerts are always on.

Alerts are displayed in the OBSERVATIONS area of the Quick Look screen.

When an alert is initiated, the device sounds a tone either at a selected time of day or at a fixed time interval. The tone then sounds each day at the selected time or interval until it is cleared through interrogation by the implantable device manager. Active tones also sound when the patient magnet is placed over the device. You can view alert details during a patient session.

Notes:

• A CareLink transmission does not clear an alert tone. The tone will continue to sound until the alert is cleared in the office (or if the DEVICE TONE is set to Off).

• Once an alert has been transmitted over the CareLink Network (if available), further transmissions for that alert condition will not occur until the alert is cleared.

• OptiVol alert tones stop sounding if the OptiVol 2.0 Fluid Index reaches 0. If the Fluid Index threshold is crossed again, another CareLink transmission is initiated and OptiVol alert tones sound at the programmed times.

• All alerts are cleared automatically when the device is interrogated with a device manager.

3.2.2.1 Patient alert process

The device can be programmed to sound a tone to alert the patient when a clinical management event or a system performance event occurs. However, the patient will not be able to determine the nature of the alert. Instruct your patients to call the clinic if they hear a device tone.

The alert event determines when the device tone will sound: when the event occurs, at a programmed time of day, or at fixed intervals. Device tones sound for up to 30 s, and they are slightly louder than the ambient noise in a typical living room.

For more information about patient alerts, refer to the implantable device app help.

3.2.2.2 Instructing the patient

It is important that patients understand that they may hear device tones emitted from their implanted device. They must know what to do when a device tone sounds.

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Warning: Make sure that patients understand that they must not carry, store, or leave the patient magnet positioned over the device. Device operation is temporarily impaired when the magnet is placed over the device and it must be moved away from the device to restore normal operation.

• Instruct patients to contact you immediately if they hear ANY tones from the device.

• Tell patients the time of day that you have programmed an alert tone to sound. If a tone sounds, patients should expect it to sound every day at that time until the alert is cleared (or until DEVICE TONE is programmed to Off).

• Advise patients that if an alert is not successfully transmitted to their personal mobile devices or to a Medtronic home communicator within 72 hours, a tone sounds each day at the programmed alert time.

• Advise patients that the alert time does not adjust for time zone changes.

• Advise patients that they may hear a steady test tone or any active alert tones if they are in the presence of a strong electromagnetic field, such as the field within a store theft detector. Advise patients that the device operation is temporarily impaired in these situations and that they should move away from the source of the interference to restore normal device operation.

Patients should also understand the purpose of the patient magnet and how and when to use it. Make sure that they know that current patient alerts sound when the patient magnet is placed over the device. Demonstrate how to place the patient magnet over the device to replay the alert tones, and review the patient magnet manual with them.

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3.2.3 Clinical management and system performance event alerts

3.2.3.1 Clinical management event alerts

Possible OptiVol fluid accumulation – This alert indicates that the OptiVol 2.0 Fluid Index

has met or exceeded the programmed OptiVol Threshold.

AT/AF Daily Burden – This alert indicates that the cumulative time in AT/AF exceeds the programmed threshold.

Avg. V. Rate During AT/AF – This alert indicates that the average ventricular rate during a selectable duration of AT/AF exceeds the programmed threshold.

Monitored VT Episode Detected – This alert indicates that 1 or more monitored VT episodes have been detected.

Daily VT/VF Episodes – This alert indicates that the total number of daily VT/VF episodes is greater than or equal to 3 episodes.

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Weekly ATP Delivered Episodes – This alert indicates that the number of episodes treated with antitachycardia pacing is greater than or equal to the programmed threshold, per week.

Number of Shocks Delivered in an Episode – This alert indicates that the number of shocks delivered in a VT/VF episode is greater than or equal to the programmed Number of Shocks Threshold value.

Total VP < 90% – This alert indicates that the cumulative percentage of ventricular pacing over the most recent 7 days was less than 90%.

3.2.3.2 System performance event alerts

RV Lead Integrity – This alert indicates that an RV lead problem is suspected, which could

indicate lead fracture. The device immediately sounds an alert tone that lasts for 30 s. This tone repeats every 4 hours, beginning at the next scheduled 4-hour time interval, and at the programmed Alert Time….

RV Lead Noise – This alert indicates that noise was detected on the RV lead, which could indicate lead fracture, breached lead insulation, lead dislodgement, or improper lead connection. The device sounds an alert tone 3 min after a lead noise episode is detected. This tone repeats every 4 hours, beginning at the next scheduled 4-hour time interval, and at the programmed Alert Time….

Lead Impedance Out of Range… – These alerts indicate that the daily lead impedance measurement for one of the implanted leads is out of range. These alerts could indicate that a lead has dislodged or is improperly connected. For all leads, the device sounds an alert tone at the programmed Alert Time…. For the RV Pacing, RV Defibrillation and SVC Defibrillation leads, the device sounds an alert tone and repeats this tone every 4 hours, beginning at the next scheduled 4-hour time interval.

Capture Management High Threshold… – These alerts indicate high capture threshold measurements. During Left Ventricular Capture Management operation (or 2nd Left Ventricular Capture Management operation), an alert occurs when a single daily measurement is high. During Right Ventricular Capture Management and Atrial Capture Management operation, an alert occurs when 3 consecutive daily measurements are high.

Low Battery Voltage RRT – This alert indicates that the daily automatic battery voltage measurement has been at or below the Recommended Replacement Time (RRT) voltage level for 3 consecutive days. When RRT has been met, the device has less than 3 months to the Elective Replacement Indicator (ERI).

Excessive Charge Time EOS… – This alert indicates that the charging period equals or exceeds the charge time threshold.

2nd LV high threshold alert is available for devices with the MPP feature.

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VF Detection OFF, 3+VF or 3+FVT Rx Off – These alerts indicate that one or more of the following conditions has occurred for at least 6 hours since the last programming: VF detection has been turned off; 3 or more VF therapies have been turned off; or FVT detection is programmed to FVT via VF and 3 or more FVT therapies have been turned off. Note that this alert sounds immediately and then every 6 hours until cleared.

For details about programmable settings for a particular parameter, see the device manual for the specific device.

3.2.3.3 Non-programmable system performance event alerts

Pacing Mode DOO, VOO, or AOO – This alert indicates that the device is programmed to

a DOO, a VOO, or an AOO pacing mode and, as such, does not deliver tachyarrhythmia therapy. The device sounds a tone daily at the programmed time.

Active Can Off without SVC – This alert indicates that the Active Can feature is disabled without an SVC lead in place, which does not provide a viable defibrillation pathway. The device sounds a tone daily at the programmed time.

Rapid Current Drain EOS indicated – This alert indicates that the battery voltage is declining faster than expected at the time that low battery Recommended Replacement Time (RRT) has been detected. This situation reduces the 3-month Prolonged Service Period to device End of Service (EOS). If this alert condition is met, the device sounds a continuous patient alert tone for 30 s. This patient alert tone repeats every 4 hours, beginning at the next scheduled 4-hour time interval, and at the programmed Alert Time. Immediately contact your Medtronic representative if a Rapid Current Drain EOS alert occurs.

Unsuccessful Wireless Transmission – This alert indicates that the device attempted a wireless transmission but that the transmission was still unsuccessful after a 72-hour period.

3.2.4 Programming Alerts

The Medtronic CareAlert SETUP screen shows either a Lead/Device Integrity Alerts view or a Clinical Management Alerts view. To toggle between views, tap either Clinical Management Alerts… or Lead/Device Integrity Alerts….

Table 3. How to navigate to parameters for Lead/Device Integrity Alerts from the Menu

button

Parameters Path

Wireless Telemetry with Monitor Alert Time…

RV Lead alert parameters:

RV Lead Integrity RV Lead Noise

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PARAMETERS > Alert…

PARAMETERS > Alert… > Lead/Device Integrity Alerts... > RV Lead… WIRELESS ALERT

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Table 3. How to navigate to parameters for Lead/Device Integrity Alerts from the Menu buttona (continued)

Parameters Path

Lead Impedance Out of Range alert parameters:

A. Pacing ENABLE A. Pacing LESS THAN A. Pacing GREATER THAN RV Pacing ENABLE RV Pacing LESS THAN RV Pacing GREATER THAN LV Pacing ENABLE LV Pacing LESS THAN LV Pacing GREATER THAN 2nd LV Pacing ENABLE 2nd LV Pacing LESS THAN 2nd LV Pacing GREATER THAN RV Defibrillation ENABLE RV Defibrillation LESS THAN RV Defibrillation GREATER THAN SVC Defibrillation ENABLE SVC Defibrillation LESS THAN SVC Defibrillation GREATER THAN

Capture Management High Threshold parameters:

A. Capture ENABLE RV Capture ENABLE LV Capture ENABLE 2nd LV Capture ENABLE

Low Battery Voltage RRT Excessive Charge Time EOS… VF Detection OFF, 3+ VF or 3+ FVT Rx Off.

The Lead/Device Integrity Alerts… label shares a toggle field with the Clinical

PARAMETERS > Alert… > Lead/Device Integrity Alerts… > Lead Impedance Out of Range… WIRELESS ALERT

PARAMETERS > Alert… > Lead/Device Integrity Alerts… > Capture Management High Threshold… WIRELESS ALERT

PARAMETERS > Alert… > Lead/Device Integrity Alerts… WIRELESS ALERT

Management Alerts… label.

The 2nd LV parameters are available when the MPP feature is programmed to On.

Table 4. How to navigate to parameters for Clinical Management Alerts from the Menu

button

Parameters Path

Wireless Telemetry with Monitor Alert Time (OptiVol)… Alert Time…

OptiVol 2.0 Fluid Settings parameters

OptiVol Alert Enable OptiVol Threshold

PARAMETERS > Alert…

PARAMETERS > Alert… > OptiVol 2.0 Fluid Settings… WIRELESS ALERT

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Table 4. How to navigate to parameters for Clinical Management Alerts from the Menu buttona (continued)

Parameters Path

AT/AF Burden and Rate Settings parameters

AT/AF Daily Burden ENABLE AT/AF Daily Burden BURDEN Avg. V. Rate During AT/AF ENABLE Avg. V. Rate During AT/AF BURDEN Avg. V. Rate During AT/AF V. RATE

VT/VF Episodes and Therapies parameters

Monitored VT Episode Detected ENABLE Daily VT/VF Episodes ENABLE Weekly ATP Delivered Episodes ENABLE Weekly ATP Delivered Episodes THRESHOLDS Number of Shocks Delivered in an Episode ENABLE Number of Shocks Delivered in an Episode THRESHOLDS

Total VP < 90% PARAMETERS > Alert…

The Clinical Management Alerts… label shares a toggle field with the Lead/Device

PARAMETERS > Alert… > AT/AF Burden and Rate Settings… WIRELESS ALERT

PARAMETERS > Alert… > VT/VF Episodes and Therapies… WIRELESS ALERT

Integrity Alerts… label.

Transmitting alerts – The ability to transmit Medtronic alerts to the CareLink Network is programmable only when the Wireless Telemetry with Monitor parameter on the Medtronic CareAlert SETUP screen is programmed to On.

Repetitive alerts – If a programmable alert is triggered so often that it loses its clinical value, you can adjust the alert threshold, program the device to improve therapy effectiveness, or turn off the alert.

3.2.5 Evaluation of alert events

The Medtronic CareAlert EVENTS log categorizes alert events as CareAlert EVENTS and OptiVol EVENTS. For each alert event, a log entry includes the date and time of the alert, a description of the event, and the measurement or information that caused the event. Up to 15 CareAlert events and the last 7 OptiVol events are stored.

Caution: Verify lead integrity when evaluating OptiVol events. Loss of RVcoil integrity due to lead fracture or insulation defect may adversely affect OptiVol events.

From the Menu button, tap DATA > CareAlert EVENTS to see the alert events stored in the Medtronic CareAlert EVENTS log.

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3.3 OptiVol 2.0 Fluid Status Monitoring

Clinical studies have shown that lung congestion is a primary complication associated with heart failure and is a frequent cause of repeated hospital admissions.

Patients with moderate to severe heart failure are at risk of further cardiac decompensation as a result of total body and thoracic fluid accumulation. Early detection of thoracic fluid accumulation may enable more timely treatment adjustments.

Clinical data suggest that changes in thoracic impedance and fluid accumulation in the thoracic cavity or lungs are inversely correlated. As the patient’s lungs become congested, thoracic impedance tends to decrease. Similarly, an increase in thoracic impedance may indicate the patient’s lungs are becoming drier.

The OptiVol 2.0 Fluid Status Monitoring feature measures the patient’s thoracic impedance using the RVcoil to Can pathway, which passes through the tissue within the thoracic cavity. Increases in thoracic fluid cause a decrease in impedance for this pathway. Decreases in thoracic fluid cause an increase in impedance for this pathway.

Notes:

• The OptiVol 2.0 Fluid Status Monitoring feature accounts for individual patient variation, including allowing the Fluid Index to increase or decrease based on recent thoracic impedance measurements.

• The OptiVol 2.0 Fluid Status Monitoring feature may not provide early warning for all fluid-related decompensations. Therefore, patients should be instructed to seek medical attention immediately any time they feel ill and need help, even if the OptiVol fluid monitoring features of their device or monitor indicate acceptable pulmonary fluid status conditions.

• The OptiVol 2.0 Fluid Status Monitoring feature is an additional source of information for patient management and does not replace assessments that are part of standard clinical practice.

3.3.1 Operation of OptiVol 2.0 Fluid Status Monitoring

3.3.1.1 Daily and reference impedances

Thoracic impedance measurements are made at regular intervals between 12:00 and 17:00. After all impedance measurements for a day have been made, the average impedance value is calculated for that day. This daily impedance value is used to update a slowly adapting trend known as the reference impedance, which is calculated by the device. In this way, a control value for each individual patient is calculated. The device uses this control value to assess impedance variations.

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The system provides a diagnostic plot that illustrates a patient’s fluid status over time. The plot is part of Cardiac Compass Trends and the Heart Failure Management Report.

Figure 1. OptiVol 2.0 Fluid Trends

1 OptiVol threshold 2 OptiVol 2.0 Fluid Index: accumulation of the difference between the daily impedance and the

reference impedance, adjusted for individual patient variation. 3 Reference impedance adapts slowly to daily impedance changes. 4 Daily impedance is the average of each day’s multiple impedance measurements.

OptiVol 2.0 Fluid Index – If the daily impedance falls below the reference impedance, this change may indicate that fluid is accumulating in the patient’s thoracic cavity. If the daily impedance remains below the reference impedance, the difference between the daily impedance values and the reference impedance values, adjusted for individual patient variation, is added to the OptiVol 2.0 Fluid Index.

While there is a difference between the daily impedance and the reference impedance, the fluid index may continue to increase. If the daily impedance begins to rise, this change may be an indication that the thoracic fluid accumulation is resolving and the fluid index may decrease. When the daily impedance returns to the reference impedance, the fluid event is considered to have ended and the OptiVol 2.0 Fluid Index resets to 0.

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OptiVol Threshold – If the daily impedance remains below the reference impedance on consecutive days, the OptiVol 2.0 Fluid Index may rise above the programmed OptiVol Threshold. If this situation occurs, the device records a Quick Look OBSERVATION and adds an entry in the OptiVol EVENTS log. The OptiVol event is considered ongoing, even if the fluid index falls below the OptiVol Threshold, until the OptiVol 2.0 Fluid Index resets to 0. The Medtronic CareAlert Monitoring feature can also transmit the event to the Medtronic CareLink Network through a Medtronic patient app or home communicator (if available). For more information, see Section 3.2, Medtronic CareAlert Monitoring, page 25.

Note: After Medtronic CareAlert Monitoring successfully transmits an OptiVol alert, the device does not retransmit the alert while the fluid event is ongoing. If the fluid event ends and the OptiVol 2.0 Fluid Index resets to 0, any subsequent OptiVol event is transmitted as a separate alert.

3.3.2 Programming OptiVol 2.0 Fluid Status Monitoring

The OptiVol 2.0 Fluid Status Monitoring parameters are located on the Clinical Management Alerts… view of the Medtronic CareAlert Setup screen.

Table 5. How to navigate to OptiVol 2.0 parameters from the Menu button

Parameters Path

Alert Time (OptiVol)… PARAMETERS > Alert…

OptiVol Alert Enable OptiVol Threshold

ADJUST REFERENCE IMPEDANCE PARAMETERS > Alert… > OptiVol 2.0 Fluid Set-

PARAMETERS > Alert… > OptiVol 2.0 Fluid Settings…

tings… > Additional Settings…

Setting the OptiVol Threshold – The OptiVol Threshold is nominally programmed to 60. Medtronic recommends that you use this setting until you have clinical experience using OptiVol 2.0 Fluid Status Monitoring with individual patients.

If the patient is experiencing too many OptiVol observations or alerts, the OptiVol Threshold may be set at too sensitive (low) a level, and you should consider increasing the OptiVol Threshold.

If the OptiVol alert tone is not sounding or is delayed when the patient has thoracic fluid accumulation, the OptiVol Threshold may be set at too insensitive (high) a level, and you should consider decreasing the OptiVol Threshold.

OptiVol alert and reference impedance initialization – The Medtronic CareAlert Monitoring feature does not transmit OptiVol alerts during the 34-day reference impedance initialization period. Medtronic recommends that you do not enable the OptiVol alert before the end of the reference impedance initialization period. You can then assess the thoracic

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impedance trend and the correlation of the daily and reference impedances under normal conditions before setting up the OptiVol alert.

Adjusting the reference impedance – Under appropriate circumstances, you can adjust the reference impedance so that it more closely matches the patient’s daily impedance measurements. This adjustment should be done only in rare cases and when the patient has stable pulmonary fluid status. The adjustment process takes several days. The reference impedance is set to the average of the last daily impedance measurement and the next 3 daily impedance measurements.

Notes:

• You should adjust the reference impedance only when all of the following conditions hold: the patient has stable pulmonary fluid status, OptiVol trends show that the patient’s daily impedance is stable, and the reference impedance has not already adjusted to the patient’s daily impedance.

• The reference impedance adjustment cannot be performed during the reference impedance initialization period.

• OptiVol alerts and observations are suspended for the first few days after an adjustment.

Suspending the OptiVol alert – You can suspend the OptiVol alert tone for 3, 5, 7, or 14 days to allow time for the patient’s fluid status to stabilize. When suspended, the OptiVol alert remains enabled, but the alert tone will not sound until the specified number of days has elapsed.

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Note: Suspending the alert tone does not change the way the Medtronic home communicator and other instruments handle alert conditions.

3.3.3 Evaluation of OptiVol 2.0 Fluid Status Monitoring

Caution: Verify lead integrity when evaluating OptiVol 2.0 Fluid Status Monitoring. Loss of

RVcoil integrity due to lead fracture or insulation defect may adversely affect the results of OptiVol 2.0 Fluid Status Monitoring.

OptiVol 2.0 Fluid Trends – OptiVol 2.0 Fluid Trends include up to 14 months of OptiVol 2.0 Fluid Trends patient data. The OptiVol 2.0 Fluid Index is a plot of the accumulation of differences, adjusted for individual patient variation, between the daily thoracic impedance value and the reference thoracic impedance value. The thoracic impedance trend plots the daily and reference impedance values. This data is included in Cardiac Compass Trends data and the Heart Failure Management Report. To access the Cardiac Compass Trends data from the Menu button, tap Quick Look > Cardiac Compass, or tap DATA > Cardiac Compass TRENDS. To create a Heart Failure Management Report, tap SESSION > HEART

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FAILURE from the Menu button. To view the saved report, tap SAVED REPORTS / DATA from the Menu button.

Quick Look OBSERVATIONS for OptiVol events – The device records an observation in the Quick Look OBSERVATIONS when the OptiVol 2.0 Fluid Index has reached or exceeded the OptiVol Threshold since the last session or if the reference impedance has been automatically adjusted. If the OptiVol 2.0 Fluid Index is still greater than 0, the observation displays the date of the first day that the OptiVol 2.0 Fluid Index was equal to or greater than the threshold and ongoing. If the OptiVol 2.0 Fluid Index has since reset to 0, the observation displays the date of the first day that the OptiVol 2.0 Fluid Index was equal to or greater than the threshold and the date that the OptiVol 2.0 Fluid Index reset to 0. To see OBSERVATIONS of OptiVol 2.0 events, from the main menu tap Quick Look.

OptiVol EVENTS log – The OptiVol EVENTS log reports up to 7 of the most recent OptiVol events. Each log entry includes an OptiVol Threshold value and the date and time of the event. To view the OptiVol EVENTS log, tap DATA > CareAlert EVENTS > OptiVol EVENTS.

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3.4 RV Lead Integrity Alert

RV lead fractures can cause oversensing, which can lead to inappropriate tachyarrhythmia detection and shock. While some lead fractures occur suddenly and provide little warning, other fractures are preceded by rapid, unexpected changes in lead impedance and short episodes of oversensing. Monitoring for these changes may provide patients with enough advance warning of a potential lead problem to avoid an inappropriate shock.

The RV Lead Integrity Alert feature is designed to provide advance warning of a potential RV lead fracture by monitoring the RV bipolar and RV tip-to-coil lead impedance, the frequency of rapid non-sustained ventricular tachyarrhythmia (High Rate-NS) episodes, and the frequency of short ventricular intervals counted on the Sensing Integrity Counter.

If the possibility of an impending RV lead fracture is indicated by the data, the RV Lead Integrity Alert feature can trigger a Medtronic CareAlert notification and an alert tone to warn the patient. In addition, the RV Lead Integrity Alert feature automatically adjusts tachyarrhythmia detection settings and diagnostic settings to avoid the delivery of an inappropriate shock.

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RV bipolar OR RVtip-to-coil

lead impedance

Response

Sensing Integrity Counter

High Rate-NS episodes

60 days

2 of 3 criteria

are met

CareAlert notification

Suspend detection during nonwireless telemetry

Adjustments to tachyarrhythmia detection

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Based on a retrospective analysis of Sprint Fidelis lead fracture data, the RV Lead Integrity Alert feature is estimated to provide 75% of patients with at least 3 days of warning in advance of a shock due to oversensing from a Sprint Fidelis lead fracture. 25% of patients will not receive a warning at least 3 days in advance of a shock due to lead fracture. Actual experience may vary. Clinicians should not rely exclusively on the RV Lead Integrity Alert feature, but continue to consider other available diagnostic information and continue routine follow-up visits. This feature should only be regarded as one part of an extensive lead integrity assessment strategy to be chosen by clinicians and their patients for determining further therapeutic or corrective action (for example, lead replacement).

3.4.1 Operation of RV Lead Integrity Alert

Figure 2. Operation of RV Lead Integrity Alert

1 Lead Integrity Alert impedance is evaluated for both RV bipolar and RV tip-to-coil pacing

polarities. If either measurement goes out of range, the impedance criterion is met.

The device continually monitors for a potential RV lead fracture using lead impedance measurements for both RV pacing lead polarities, the Sensing Integrity Counter, and High Rate-NS episode data. It identifies a potential lead fracture if at least 2 of the following criteria have been met within the past 60 days:

• An RV pacing lead impedance measurement for either polarity is less than 50% or greater than 175% of the baseline impedance. The baseline measurement is the median of the previous 13 daily measurements. A separate baseline is calculated for each RV pacing vector. The RV bipolar and RV tip-to-coil impedance measurements are taken at the same time each day.

• The ventricular Sensing Integrity Counter is incremented by at least 30 within a period of 3 consecutive days or less.

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Note: The SENSING INTEGRITY COUNTER total displayed on the BATTERY AND LEAD MEASUREMENTS window is the number of short ventricular intervals that occurred since the last patient session. Therefore, the total could exceed 30 without satisfying the alert criteria if the total was reached during a period of more than 3 consecutive days.

• The device senses 2 High Rate-NS episodes with a 4-beat average R-R interval of less than 220 ms.

If either the DEVICE TONE or the WIRELESS ALERT parameter for the RV Lead Integrity alert is programmed to On, the device responds to a potential RV lead fracture with an alert tone, a Medtronic CareAlert notification, and automatic adjustments to tachyarrhythmia detection. When at least 1 High Rate-NS episode occurs or if the alert criteria are met, the device automatically adjusts EGM storage operation.

If both the DEVICE TONE and the WIRELESS ALERT alert parameters for the RV Lead Integrity Alert are programmed to Off, the device does not trigger a Medtronic CareAlert notification or an alert tone, and it does not adjust tachyarrhythmia detection parameters. However, it records a Quick Look OBSERVATION for the lead warning, and it makes adjustments to EGM storage.

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3.4.1.1 RV Lead Integrity Alert tones and CareAlert notifications

When the criteria for the RV Lead Integrity Alert are met, the device immediately sounds an alert tone. The tone sounds again every 4 hours beginning at the next scheduled 4-hour time interval (00:00, 04:00, 08:00…). The tone also sounds at the programmed Alert Time… and when a magnet is placed over the device. The tone continues to sound until the alert is cleared (or until DEVICE TONE is programmed to Off). If the WIRELESS ALERT for the RV Lead Integrity Alert is programmed to On, the device also attempts to send a wireless transmission to the home communicator.

3.4.1.2 Automatic adjustments to tachyarrhythmia detection

When the RV Lead Integrity Alert is triggered, the device automatically programs the VF Initial Beats to Detect parameter to 30/40 (if it was less). If necessary, the device automatically adjusts the Monitored VT Beats to Detect parameter and sets AT/AF Detection to Monitor.

In addition, after the RV Lead Integrity Alert has been triggered, the device automatically suspends tachyarrhythmia detection when it is interrogated using nonwireless telemetry by a device manager. The device suspends detection to prevent inappropriate therapy delivery during the telemetry session when a lead issue is suspected. Tachyarrhythmia detection can be resumed by tapping RESUME at the top of the implantable device app screen or by ending the nonwireless session.

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Note: This suspension behavior occurs for all nonwireless sessions until 3 days have passed since the alert was cleared or the device was interrogated.

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3.4.1.3 EGM storage changes

When at least 1 High Rate-NS episode occurs, the device automatically adjusts EGM storage operation in order to provide more diagnostic data to help identify a lead-related issue. The device programs the Pre-arrhythmia EGM parameter to On - 1 month (unless the previous setting provided more than 30 days of Pre-arrhythmia EGM storage remaining).

Notes:

• The Pre-arrhythmia EGM parameter displays the programmed setting even when the device adjusts EGM storage automatically after a High Rate-NS episode has occurred.

• The changes to EGM storage occur even when the DEVICE TONE and WIRELESS ALERT parameters for RV Lead Integrity alert are programmed to Off.

If the Lead Impedance and Sensing Integrity Counter criteria are met, the device also changes the criteria for storing High Rate-NS episodes, allowing a High Rate-NS episode with EGM data to be recorded if a single ventricular interval less than 200 ms occurs. This condition persists until a High Rate-NS episode occurs or until you interrogate the device.

3.4.2 Evaluation of RV Lead Integrity Alert

If the device is sounding an alert tone or if the implantable device app indicates that an alert event has occurred, review the alert messages and evaluate the diagnostic data to determine the likelihood of a lead integrity issue.

CareAlert window – When the device is interrogated, a CareAlert window notifies you that an alert condition exists, including the RV Lead Integrity Alert.

Quick Look observations – Check the Quick Look OBSERVATIONS list to verify that there is an RV Lead Integrity warning.

For detailed information about viewing and interpreting all of the information available from the Quick Look screen, see Section 3.1, Quick Look summary data, page 23.

Medtronic CareAlert events – To verify that there is an RV Lead Integrity warning, tap DATA > CareAlert EVENTS from the Menu button.

Sensing integrity counter – To access the sensing integrity counter, tap DATA > BATTERY AND LEAD MEASUREMENTS > Sensing Integrity Counter from the Menu button.

Check the Short V-V Intervals for evidence of oversensing. For more information, see Section 3.15, Device and lead performance data, page 63.

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Arrhythmia Episodes (High Rate-NS) – If an RV Lead Integrity warning is listed in the Quick Look OBSERVATIONS, tap DATA > ARRHYTHMIA EPISODES from the Menu button to see details of the warning.

Check the High Rate-NS episodes in the ARRHYTHMIA EPISODES window. A High Rate-NS episode has an average ventricular rate greater than 273 bpm (less than 220 ms). If 2 or more High Rate-NS episodes are recorded, lead noise oversensing may have occurred. Review the stored EGM to determine the cause of the oversensing.

RV lead impedance trends – To access RV lead impedance trends, tap DATA > LEAD IMPEDANCE TRENDS, then select RV Pacing Impedance from the LEAD TRENDS pulldown menu. Check for a sudden change in the impedance measurements for BIPOLAR or TIP TO COIL. If 1 or more measurements are > 175% or < 50% of the baseline value, then the lead impedance is abnormal.

Note: The BIPOLAR/TIP TO COIL lead trend graph combines the BIPOLAR and TIP TO COIL trends into a single view.

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3.5 Cardiac Compass Trends

An analysis of clinical information collected over a long term can help you to follow changes in a patient’s condition and correlate these changes with variations in device programming, medication, patient activity, or symptoms.

Cardiac Compass Trends data provides information about a patient’s condition over the last 14 months. Graphs show trends in tachyarrhythmias, physical activity, heart rates, device therapies, and information related to heart failure. Dates and event annotations allow you to correlate trends from different graphs. The trends can also help you to assess whether device therapies or antiarrhythmic drugs are effective.

Data storage for the Cardiac Compass Trends feature is automatic. No setup is required. The device begins storing data after the device is implanted. Each day thereafter, the device stores a set of trend data. After 14 months of data are collected, the device continues storage by overwriting the oldest stored data with new data.

Note: The schedule for collecting daily measurements and the time annotations displayed in the trends are both based on the device clock.

To access Cardiac Compass Trends data, tap Cardiac Compass if you are in the Quick Look screen, or tap DATA > Cardiac Compass TRENDS from the Menu button.

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3.5.1 Information provided by Cardiac Compass Trends

The Cardiac Compass Trends data includes the following types of information:

• Programming and interrogation event annotations

• Trend graphs for AT/AF

• Trend graphs for VT/VF

• Trend graphs for pacing, rate response, and patient activity

• Trend graphs for heart failure

3.5.1.1 Event information

Figure 3. Event annotations

1 Current session indicator 2 Last session indicator

3 High-voltage therapy indicator

Programming and interrogation events – Annotations show when the device was interrogated or programmed to allow possible correlations between device parameter changes and other clinical trends.

When the patient is evaluated during an office visit, an I annotation is added for a day on which the device is interrogated, and a P annotation is added for a day on which any programmable parameter is changed (except for temporary changes). If the device is interrogated and programmed on the same day, only a P is displayed.

When the patient is evaluated during a remote monitoring session, an I annotation with a line beneath it is added to the data.

A vertical line runs through all the graphs to indicate the beginning of the current session. If applicable, the last session is also marked with a vertical line.

One or more shocks per day – Annotations show when the device delivered a high-voltage therapy (an automatic defibrillation therapy, a cardioversion therapy, or an atrial shock

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therapy). Each annotation indicates the delivery of one or more ventricular (V) or atrial (A) high-voltage therapies on a single day.

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3.5.1.2 VT/VF information

Figure 4. VT/VF arrhythmia trend graphs

Treated VT/VF episodes/day – The history of ventricular tachyarrhythmias can be helpful

in revealing correlations between clusters of episodes and other clinical trends.

Each day, the device records the total number of spontaneous VT and VF episodes for which a therapy was started. This count can include therapies that were started and aborted. It does not include episodes that were only monitored.

V. rate during VT/VF (bpm) – This trend can provide an indication of the effects of antiarrhythmic drugs on VT and VF rates and gives a better understanding of the safety margins for detection.

The graph displays the median ventricular rate during spontaneous VT and VF episodes. Multiple points on one day represent multiple episodes with different median rates. The horizontal lines indicate the programmed VF, VT, and FVT detection rates, if applicable.

Non-sustained VT episodes/day – This trend can help you to correlate patient symptoms (such as palpitations) to non-sustained VT episodes and can indicate a need for further investigation into the status of the patient.

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3.5.1.3 AT/AF information

Figure 5. AT/AF arrhythmia trend graphs

AT/AF total hours/day – This trend may help you to assess the need to adjust the patient’s

device or drug-based therapies. This trend may also reveal the presence of asymptomatic episodes of AT/AF.

The device records a daily total for the time the patient spent in atrial arrhythmia. The time in AT/AF is calculated from the point of AT/AF onset. This trend may be reported in hours (0 to

24) or minutes (0 to 60) per day depending on the maximum duration per day. For more information, see Section 5.1, AT/AF detection, page 182.

V. rate during AT/AF (bpm) – You can use this trend to perform the following assessments:

• Correlate patient symptoms to rapid ventricular responses to AT/AF

• Assess VT/VF detection safety margins and modify programming to avoid treating rapidly conducted AT/AF as VT/VF

• Prescribe or titrate antiarrhythmic and rate control drugs

• Assess the efficacy of an AV node ablation procedure

The graph plots average ventricular rates during episodes of atrial arrhythmia each day. The vertical lines show the difference between the average rate and the maximum sensed ventricular rate each day. The horizontal lines indicate the programmed VF, FVT, and VT detection rates, if applicable.

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3.5.1.4 Pacing and patient activity information

Figure 6. Pacing and rate response trend graphs

% CRT Pacing/day – For devices that include the EffectivCRT Diagnostic feature, this trend

displays the percentage of ventricular pacing per day and the percentage of effective CRT pacing per day.

Avg V. rate (bpm) – The day and night heart rates provide information that can have the following clinical uses:

• Objective data to correlate with patient symptoms

• Indications of autonomic dysfunction or symptoms of heart failure

• Information regarding diurnal variations

For this trend, Day is the 12-hour period between 08:00 and 20:00 and Night is the 4-hour period between 24:00 and 04:00 (as indicated by the device clock).

Patient activity hours/day – The patient activity trend can provide the following information:

• Information about a patient’s exercise regimen

• An objective measurement of patient response to changes in therapy

• An early indicator of progressive diseases like heart failure, which cause fatigue and a consequent reduction in activity

The patient activity trend is a 7-day average of data derived from the device rate response accelerometer. It is reported only after 14 days of data have been collected.

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3.5.1.5 Heart failure information

Figure 7. OptiVol 2.0 Fluid Trends

Note: Trends in this figure are shown as they appear in the saved Cardiac Compass Report.

OptiVol 2.0 Fluid Index – A decrease in thoracic impedance may be an early indicator of

fluid accumulation associated with heart failure. The OptiVol 2.0 Fluid Index trend displays the accumulated difference between the measured daily thoracic impedance and the reference impedance, adjusted for individual patient variation. If the daily impedance is less than the reference impedance, this situation may indicate that the patient’s thoracic fluid has increased. The horizontal line shows the programmed value of the OptiVol Threshold.

Caution: Verify lead integrity when evaluating the OptiVol 2.0 Fluid Index trend. Loss of RVcoil integrity due to lead fracture or insulation defect may adversely affect the results of the OptiVol 2.0 Fluid Index trend.

For more information, see Section 3.3, OptiVol 2.0 Fluid Status Monitoring, page 33.

Note: The OptiVol 2.0 Fluid Status Monitoring feature provides an additional source of information for patient management and does not replace assessments that are part of standard clinical practice.

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Thoracic impedance (ohms) – The Thoracic impedance (ohms) trend allows you to compare the daily average measured thoracic impedance to the reference impedance values. The reference impedance changes slightly from day to day to adapt slowly to the daily impedance.

Figure 8. Heart rate variability trend

Note: The trend in this figure is shown as it appears in the saved Cardiac Compass Report.

Heart rate variability (ms) – Reduced variability in the patient’s heart rate may help you to

identify heart failure decompensation. The device measures each atrial interval and calculates the median atrial interval every 5 min. It then calculates and plots a variability value (in ms) for each day.

Note: The calculation of heart rate variability does not include events that occur during arrhythmia episodes.

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3.6 Heart Failure Management Report

An analysis of clinical information related to heart failure can help you to follow changes in a patient’s condition and correlate these changes with variations in device programming, medication, patient activity, or symptoms.

The Heart Failure Management Report provides a picture of the patient’s condition over the short term and the long term with a focus on heart failure management. A summary of clinical data recorded since the last follow-up appointment shows information about arrhythmia episodes and therapies. Clinical trend graphs show long-term trends in heart rates, arrhythmias, and fluid accumulation indicators over the last 14 months.

The Heart Failure Management Report is based on data and measurements displayed on the PATIENT INFORMATION and Quick Look screens and in Cardiac Compass Trends. Data storage for the Heart Failure Management Report is automatic. No setup is required.

Note: The time annotations displayed on the report are based on the device clock.

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To save a Heart Failure Management Report, tap SESSION > HEART FAILURE from the Menu button. To view the saved report, or to print it or send it to the destination of your choice, tap SAVED REPORTS / DATA.

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3.6.1 Information provided by the Heart Failure Management Report

The Heart Failure Management Report provides information about the patient and the patient’s clinical status since the last follow-up appointment. It displays events that have occurred during the reporting period and provides graphs that can help you to assess OptiVol 2.0 Fluid Trends and clinical trends related to heart failure.

3.6.1.1 Patient information

Patient information is based on data entered in the PATIENT INFORMATION screen. This screen includes any medical history and dates of measurements.

3.6.1.2 Clinical Status and Observations

The Clinical Status and the Observations sections of the Heart Failure Management Report include information that can be useful for managing heart failure. This information is also available on the Quick Look screen. For more information about Quick Look data, see Section 3.1.

The Heart Failure Management Report shows the following information:

• Arrhythmia episode information that shows the number of treated VT/VF episodes and the number of treated and monitored AT/AF episodes recorded since the last follow-up appointment

• Ventricular pacing and atrial pacing shown as percentages of the total time during the reporting period

• The battery status at the start of the session, indicated as OK, RRT (Recommended Replacement Time), ERI (Elective Replacement Indicator), or EOS (End of Service)

• System-defined observations and CareAlert alerts that relate to heart failure

3.6.1.3 Cardiac Compass Trends data

The Heart Failure Management Report also includes all Cardiac Compass Trends data (see

Section 3.5, Cardiac Compass Trends, page 41), including the OptiVol 2.0 Fluid Trends (see Section 3.3, OptiVol 2.0 Fluid Status Monitoring, page 33).

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3.7 Arrhythmia Episodes data

The device stores several different types of data for arrhythmia episodes. The episode log summarizes key data for all episodes. Each episode record includes detailed information, including an interval plot, stored EGM, and episode text.

There are several navigation paths to arrhythmia episodes data from the Menu button:

• To see data for all arrhythmia episodes, tap DATA > ARRHYTHMIA EPISODES.

• To see data for treated arrhythmia episodes, tap Quick Look > TREATED.

• To see data for monitored arrhythmia episodes, tap Quick Look > MONITORED.

For more information about how to use the ARRHYTHMIA EPISODES window, refer to the implantable device app help.

3.7.1 Episode log

The device stores the following summary information for each arrhythmia episode, recorded on the ARRHYTHMIA EPISODES window:

• Type – the type of episode

• ATP – the number of ATP sequences delivered (if any)

• Shocks – the number of shocks or the energy delivered (if any)

• Success – whether the last therapy delivered was successful

• Date – the date that the episode occurred

• Time – the time of day that the episode occurred

• Duration – the length of time that the episode persisted

• A/V bpm – the average atrial and ventricular beats per minute (bpm)

• Max V – the maximum ventricular beats per minute (bpm)

• EGM – if EGM data is available for the episode

Calculating the average rate – For AT/AF, VT-Mon, and VT-NS episodes, the average atrial and ventricular rates are calculated from the average cycle lengths throughout the entire episode. For VT/VF, SVT, and VOS episodes, the average atrial and ventricular rates are the average of the 4 beats at detection or immediately prior to withholding detection.

Display of the maximum ventricular rate – If the ventricle was paced during an AT/AF episode, the maximum ventricular rate appears in the log as VP. For VT-NS episodes, the maximum ventricular rate is not displayed.

Patient-activated symptom log entries – If your patient has a Medtronic patient assistant instrument, a Symptom entry is recorded in the arrhythmia episode log each time that the

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patient uses the instrument to report symptoms. This log entry will include the date, time, and average atrial and ventricular cycle lengths. If an arrhythmia episode is already in progress when the patient records a symptom episode, the device does not store an additional log entry. Instead, the episode text for the ongoing arrhythmia episode is annotated with the statement “Patient Symptom detected during episode”.

Notes:

• Episodes that occur during a device session are not available to view in the episode records until an interrogation is performed. To view the episode information, interrogate the device after episode termination.

• If an interrogation is performed while an episode is in progress, the type, date, and time of the episode are provided. To view additional episode information, interrogate the device after episode termination.

• For most episode types, if the log capacity is reached, data from the most recent episode overwrites the oldest episode data in the log. For High Rate-NS episodes, if the log capacity for High Rate-NS episodes has been reached and an RV Lead Integrity Alert is triggered, no new episodes are added to the High Rate-NS log until the alert is cleared. This safeguard allows you to view the episodes that triggered the alert. Once the RV Lead Integrity Alert is cleared, the device again records High Rate-NS episode data.

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3.7.2 Episode records

The device stores detailed information about the arrhythmia episodes recorded in the episode log. An arrhythmia episode record contains the following information:

• An interval plot

• A strip chart of the stored EGM (if available)

• A text summary

• A QRS display showing Wavelet template match scores. For more information, see Section 5.4, Wavelet, page 204.

3.7.2.1 Episode interval plot

The device records the durations of the V-V and the A-A intervals that occur during the episode. The episode interval plot graphs these interval durations vs time. The episode interval plot also includes the following information for an episode:

• Programmed detection intervals

• Point of detection or detection withheld

• Point of onset for AT/AF episodes

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• Points of therapy delivery

• Point of episode termination

Note: The device may truncate data storage during an episode to conserve device memory.

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3.7.2.2 Episode EGM

The device receives EGM data on 3 separate channels: EGM 1, EGM 2 (Wavelet), and EGM

3. The SOURCE parameter for each channel defines the electrodes between which the device records the EGM signal. The RANGE parameters define the upper and lower amplitude limits of each recorded signal in mV. Using the Monitored data collection parameter, you can select a set of 2 EGM channels for arrhythmia episode record storage.

The EGM data for each episode record is accompanied by the following additional information:

• Markers that show the classification of cardiac events by the device

• Interval measurements

• Decision Channel annotations that identify when tachyarrhythmia detection occurred and which type of rhythm was detected:

– AT/AF Detection: detected AT or AF episode

– Fast AT/AF Detection: detected AT or AF episode with a rate in the Fast AT/AF zone

– FVT: detected FVT episode

– FVT+SVT: detected FVT with SVT episode

– VF: detected VF episode

– VF+SVT: detected VF with SVT episode

– VT: detected VT episode

– VT+SVT: detected VT with SVT episode

– VTM: monitored VT episode

– VTM+SVT: monitored VT with SVT episode

EGM data storage and device memory conservation – For VT/VF or VT Monitor episodes, the device begins to store ventricular EGM data when 3 consecutive intervals have occurred in the VT, VT Monitor, or VF zone.

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To conserve device memory, EGM data is stored only during specific parts of an episode:

• Prior to episode detection

• Before and after the first tachyarrhythmia therapy is delivered

• Prior to episode termination

Long episodes show gaps in the EGM between these events. For AT/AF episodes, the device begins to store atrial EGM data when the device detects

AT/AF Onset. The device stores up to 5 s of EGM data before AT/AF detection, regardless of Pre-arrhythmia EGM operation.

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3.7.2.3 Episode text

The device stores details with each episode record that are displayed in text form:

• Episode number

• Episode type

• Date, time, and duration of the episode

• Maximum atrial and ventricular rates during the episode

• Median atrial or ventricular rate during the episode (depending on the episode type)

• Patient activity at the onset of the episode, along with the calculated sensor rate associated with the level of activity

• Programmed parameter settings related to sensing, tachyarrhythmia detection, tachyarrhythmia therapy, and EGM sources

• List of other criteria triggered by the episode

• For treated AT/AF episodes, the sequence of ATP therapies and a summary of the number of ATP therapies delivered

3.7.2.4 Episode QRS data

To see the QRS data stored by the Wavelet feature, tap the episode QRS option.

The QRS data is available for SVT, VF, VT, VT Monitor, FVT, and VOS episodes if the Wavelet criterion is programmed to On or Monitor when those episodes occur.

The QRS data shows waveform diagrams of up to 8 recorded QRS complexes, with the current template overlaid on each waveform. For each QRS complex, the match percentage and classification (Match or No Match) are also displayed. For more information, see Section 5.4, Wavelet, page 204.

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Note: If no template is available when an episode is recorded, the QRS complexes appear with no match percentages or classifications.

3.7.3 Programming Arrhythmia Episodes data collection

Data collection is automatic and cannot be turned off. However, several preference settings that are useful for controlling the display of episode data are available on the DATA COLLECTION SETUP window. These settings also control the Live Rhythm Monitor display.

Table 6. How to navigate to parameters for data collection preferences from the Menu button

Parameters Path

LECG SOURCE LECG RANGE

EGM 1 SOURCE EGM 1 RANGE

EGM 2 (Wavelet) SOURCE EGM 2 (Wavelet) RANGE

EGM 3 SOURCE EGM 3 RANGE

Pre-arrhythmia EGM

PARAMETERS > Data Collection Setup…

LECG SOURCE – You can choose to display the Leadless ECG waveform on the LECG channel. Leadless ECG is an approximation of a surface ECG signal through the Can to SVC source and is available only when an SVC coil is present. You can also choose to display the waveform from the RVcoil to Aring source or the Can to Aring source on the LECG channel.

Note: The Leadless ECG option cannot be removed from the Live Rhythm Monitor.

For more information, refer to the implantable device app help.

EGM SOURCE – For each EGM channel, define the source electrodes between which the device records EGM signals.

Note: The cardiac interval measurements of the device are always based on the signals sensed through the programmed sensing polarity (not the stored diagnostic EGM). Therefore, your selection of EGM sources does not affect tachyarrhythmia interval criteria, synchronization, and therapy.

EGM RANGE and LECG RANGE – Select a range for each EGM channel and the LECG channel. The RANGE setting affects the resolution of the signal; the lower the setting, the higher the resolution. If the signal is illegible or clipped, consider changing the range selection.

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Monitored – This parameter allows you to select which 2 sources you want to use to record monitored episodes.

Pre-arrhythmia EGM – Indicate whether you want to store EGM data collected prior to an episode. When Pre-arrhythmia EGM storage is programmed to On Continuous, the device collects up to 10 s of EGM data before the onset of VT/VF, VT Monitor, or the detection of SVT episodes. If Pre-arrhythmia EGM is programmed to Off, the episode record stores only intervals and no EGM at the beginning of each VT/VF, VT Monitor, or SVT episode. The device stores up to 5 s of EGM before AT/AF detection regardless of the Pre-arrhythmia EGM storage setting.

Note: Pre-arrhythmia EGM storage keeps the EGM circuitry enabled at all times, and it therefore reduces device longevity.

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3.8 Episode and therapy counters

The implantable device app allows you to view stored data about the number of times VT/VF and AT/AF episodes and therapies have occurred.

The count data for ventricular episodes includes the number of premature ventricular contractions (PVCs), Ventricular Rate Stabilization (VRS) paces, and monitored and non-sustained episodes. The count data for ventricular episodes also includes the number of episodes for which detection and therapy were withheld due to the application of supraventricular tachycardia (SVT) and ventricular oversensing (VOS) discrimination features.

The count data for atrial episodes includes the number of monitored, non-sustained, treated, and pace-terminated episodes.

3.8.1 VT/VF episode counters

The device records the following types of counter data, listed under VT/VF EPISODES, related to ventricular arrhythmias since the last session, and for the lifetime of the device:

VF, FVT, and VT – The number of episodes of each tachyarrhythmia.

Monitored VT – The number of VT Monitor episodes.

VT-NS – The number of non-sustained ventricular tachyarrhythmias.

High Rate-NS – The number of high rate non-sustained ventricular tachyarrhythmia

episodes.

PVC Runs (2-4 beats) – The average number of runs per hour of premature ventricular contractions (PVCs) in which 2, 3, or 4 consecutive ventricular events are premature.

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PVC Singles – The average number of single PVCs per hour. PVCs in PVC runs are not counted as PVC singles.

Runs of VRS Paces – The average number of times per hour that 2 or more consecutive ventricular events are Ventricular Rate Stabilization (VRS) pacing pulses (VRS escape interval timeouts).

Single VRS Paces – The average number of single VRS pacing pulses (VRS escape interval timeouts) per hour. VRS paces in runs of VRS paces are not counted as single VRS paces.

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3.8.1.1 SVT / V. OVERSENSING episode counters

The device records the number of episodes where therapy was withheld since the last session, and for the lifetime of the device:

SVT: VT/VF Rx Withheld – The number of episodes initially detected for each supraventricular tachycardia (SVT) discrimination feature, causing withholding of VT/FVT/VF detection and therapy.

Note: Only SVTs with rates in the treated zones are included.

V. Oversensing: VT/VF Rx Withheld – The number of episodes initially detected as TWave

Discrimination or RV Lead Noise Discrimination (ventricular oversensing discrimination features) for which VT/FVT/VF detection and therapy were withheld.

3.8.2 VT/VF therapy counters

The device records the following types of counter data, listed under VT/VF RX, related to ventricular arrhythmia therapies since the last session and for the lifetime of the device:

VT/VF THERAPY SUMMARY – These event counters include the following event metrics:

• Pace-terminated tachyarrhythmias

• Shock-terminated tachyarrhythmias

• Total VT/VF shocks

• Aborted charges

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VT/VF THERAPY EFFICACY SINCE LAST SESSION – These event counters track the following event metrics:

• The number and types of VF, FVT, and VT therapies delivered

• Delivered therapies that were successful (that is, if no redetection occurred)

• For VT and FVT therapies, if redetected episodes accelerated and were redetected as faster tachyarrhythmias

The 6 listed therapies refer to Rx1 through Rx6 for each episode type.

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3.8.3 AT/AF episode counters

The device records the following types of counter data related to atrial arrhythmias, listed under AT/AF EPISODES, since the last session and for the lifetime of the device:

% of Time AT/AF – The percentage of total time in AT/AF. AT/AF is defined as starting from AT/AF onset.

Average AT/AF time/day – The average time in AT/AF per day. AT/AF is defined as starting from AT/AF onset.

Monitored AT/AF Episodes – The average number of monitored AT/AF episodes per day. AT/AF is defined as starting from AT/AF detection.

Treated AT/AF Episodes – The average number of treated AT/AF episodes per day. AT/AF is defined as starting from AT/AF detection.

Pace-Terminated Episodes – The percentage of pace-terminated episodes for the session. AT/AF is defined as starting from AT/AF detection.

% of Time Atrial Pacing – The percentage of time that atrial pacing was performed.

% of Time Atrial Intervention – The percentage of time that atrial pacing was performed

due to atrial intervention pacing (Atrial Rate Stabilization or Atrial Preference Pacing). This percentage is of total time, not of atrial pacing time.

AT-NS (> 6 beats) – The average number of non-sustained AT (AT-NS) episodes per day.

3.8.4 AT/AF therapy counters

The device records the following types of counter data related to atrial tachyarrhythmia therapies, listed under AT/AF RX, since the last session:

FAST AT/AF RX – The number of episodes for which therapy was delivered (by therapy type) and the percentage of successfully terminated episodes per therapy.

AT/AF RX – The number of episodes for which Ramp, Burst, or Ramp+ therapy was delivered, and the percentage of successfully terminated episodes per therapy.

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ATP RX VERSUS – The episodes for which iATP therapy for AT/AF was delivered (by interval, in ms and bpm), and successfully terminated.

ATP treated episodes by cycle length – The number of ATP treated episodes and the percentage terminated, in 7 groups of cycle lengths.

ATP Sequences – The number of atrial ATP sequences that were delivered and the number that were aborted.

Automatic Shocks – The number of automatic atrial defibrillation therapies that were delivered and the number of episodes that were not terminated.

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3.9 Flashback data

The Flashback feature records atrial intervals and ventricular intervals that occur immediately prior to tachyarrhythmia episodes or the most recent interrogation. The feature plots the interval data over time, and it allows you to save a report of the collected data. The graphed data can help you assess the patient’s heart rhythm and the performance of other features, such as Rate Response.

The Flashback feature automatically records up to a total of 2000 V-V and A-A intervals and stored markers for the following events:

• The most recent interrogation

• The most recent VF episode

• The most recent VT episode

• The most recent AT/AF episode

To see Flashback data for the most recent device interrogation, tap DATA > INTERROGATION FLASHBACK.

To see Flashback data for the most recent VF episode, VT episode, or AT/AF episode, perform the following steps:

1. Tap DATA > ARRHYTHMIA EPISODES.

2. In the ARRHYTHMIA EPISODES window, tap on the episode you choose to view, then tap the expand (+) icon in the lower-right corner of the window.

3. Tap FLASHBACK.

If 2 or more episodes are detected within 15 min, the Flashback data before the episodes may be truncated.

Note: When an episode is detected, Flashback data storage is suspended until the episode terminates.

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3.10 Ventricular sensing episodes

The device defines a ventricular sensing episode as a period of time when ventricular pacing is inhibited because of the patient’s intrinsic ventricular activity. Extended periods of ventricular sensing can inhibit CRT pacing, resulting in loss of synchrony and possible worsening of heart failure symptoms. The system provides diagnostic information to help you identify the cause of ventricular sensing episodes and reprogram the device to avoid them.

The data collected for a ventricular sensing episode includes the date and time, the duration, the intervals and markers, the maximum atrial and ventricular rates, and an indication of whether the episode was part of a tachyarrhythmia.

The device begins collecting data for a ventricular sensing episode after a programmable number of consecutive ventricular senses occurs. It stops collecting data for an episode when a programmable number of consecutive ventricular paced events occurs.

Notes:

• The device classifies V. Sense Response or V. Safety Pacing events as sensed events when collecting data for a ventricular sensing episode. As a result, the pacing therapy provided by these features does not prevent the detection of ventricular sensing episodes.

• Ventricular pacing during an Atrial Tracking Recovery intervention is not included in the ventricular sensing episode termination count.

• See the following sections for more information:

– Section 4.19, Ventricular Sense Response, page 159

– Section 4.16, Ventricular Safety Pacing, page 152

– Section 4.18, Atrial Tracking Recovery, page 157

3.10.1 Programming ventricular sensing episode parameters

Table 7. How to navigate to ventricular sensing episode parameters from the Menu button

Parameters Path

COLLECT IF: Consecutive VS > = END COLLECTION IF: Consecutive VP > =

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For devices with the AdaptivCRT algorithm programmed to an adaptive value and the parameter COLLECT IF: Consecutive VS > = programmed to 5 senses, a ventricular sensing episode is stored every 16 hours. These episodes occur each time that waveform width measurements are conducted. For more information, refer to Section 4.5, AdaptivCRT, page 110.

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3.11 Rate Drop Response episodes

Rate Drop Response is a pacing feature that monitors the heart for significant rate drops and responds by pacing the heart at an elevated rate (see Section 4.11, Rate Drop Response, page 140). When the Rate Drop Response feature is programmed to On, the device records data about episodes that meet the programmed rate drop detection criteria. This data is useful for analyzing rate drop response episodes and the events leading up to them. You can view and save data for the 10 most recent episodes.

The device stores the following summary information for each Rate Drop Response episode:

• Type of episode: Drop or LowRate

• Date and Time of the episode

• Ventricular rate (Detection V. Rate) at the point of detection

• Peak ventricular rate (Peak V. Rate) before detection (Drop episodes only)

The following detailed information is provided for each Rate Drop Response episode:

• A PLOT view that shows the durations of the V-V and A-A intervals that occur during the episode

• A MARKERS view that shows the type of events that occurred during the episode

• A TEXT view that shows the Rate Drop Response settings in effect at the start of the programming session

To access Rate Drop Response episode data, tap DATA > RATE DROP RESPONSE EPISODES.

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3.12 EffectivCRT Episodes

The EffectivCRT EPISODES window provides diagnostic information to help you identify the cause of ineffective CRT pacing. The screen provides data from the 5 most recently collected episodes of ineffective CRT pacing. Each episode record displays the following data:

• The Date and Time of the episode (note that data collection begins 25 min after the hour)

• The average atrial and ventricular beats per minute (Avg bpm (A/V)) at the time of the episode

• An indication of whether an atrial tachyarrhythmia or atrial fibrillation (AT/AF) was present

A review of each EffectivCRT episode is provided in the lower-right corner of the EffectivCRT EPISODES window, if data is available. When this panel is expanded, it includes the following data:

• A 10 s EGM strip chart

• Event markers

• An indication of whether each ventricular pace was effective (Y indicates Yes) or ineffective (N indicates No).

Note: Ventricular Safety Pacing (VSP) paces and Ventricular Sense Response (VSR) paces are not included in the EffectivCRT episode review.

The EffectivCRT Episodes screen displays data collected by the EffectivCRT Diagnostic feature, which collects and stores data when ineffective pacing criteria are met. For more information, see Section 3.17, EffectivCRT Diagnostic, page 70.

During the EffectivCRT Diagnostic analysis, the device creates an EffectivCRT Episode record when all of the following occur:

• 8 consecutive ventricular events are senses, safety paces, VSR paces, LV paces, or biventricular paces without effective CRT pacing.

• At least 5 of those events are LV paces or biventricular paces without effective CRT pacing.

To access EffectivCRT EPISODES data, tap DATA > EffectivCRT EPISODES.

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3.13 MVP mode switches data

The MVP pacing modes reduce unnecessary ventricular pacing by providing AAI(R) mode pacing when AV conduction is intact and switching to the DDD(R) mode if AV conduction is lost. For more information about the MVP pacing modes (AAIR<=>DDDR and AAI<=>DDD), see Section 4.3, Managed Ventricular Pacing (MVP), page 94.

When the device is programmed to an MVP pacing mode and switches from an AAI(R) mode to a DDD(R) mode, it records an MVP mode switch entry, which includes the following information:

• Type of mode switch

• Date and time when the mode switch occurred

• Median ventricular rate at the time of the mode switch

• AV interval at the time of the mode switch

The device stores entries for the 10 most recent MVP mode switches to the DDD(R) mode. The MVP mode switches data is displayed with annotations showing the dates of patient sessions and CareLink transmissions. The data also includes a count of MVP mode switches since the last session.

To access the MVP mode switches data from the Menu button, tap DATA > MVP MODE SWITCHES.

3.14 Rate Histograms

Information about heart rates recorded between patient sessions can help you to monitor a patient’s condition to assess the effectiveness of therapies. The Rate Histograms feature shows the distribution of atrial and ventricular rates recorded Prior to Last Session and Since Last Session.

To access the rate histograms data from the Menu button, tap DATA > RATE HISTOGRAMS.

3.14.1 Numerical data

% of Time – This data represents the percentage of time that the device delivered ventricular

pacing (Total VP) and atrial pacing (Total AP), regardless of the presence of AT/AF.

% of Time (out of AT/AF) – This section shows the patient’s conduction status as the percentage of the total time that the device paced or sensed during the collection period

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when the patient was not in AT/AF. The percentages represent the aggregate daily count of the following events:

• AS-VS: atrial sense – ventricular sense

• AS-VP: atrial sense – ventricular pace

• AP-VS: atrial pace – ventricular sense

• AP-VP: atrial pace – ventricular pace

The following pacing data out of AT/AF is also included:

• Total VP equals the percentage of time the device paced in one or both ventricles.

– Effective equals the percentage of effective ventricular pacing.

– Ineffective equals the percentage of ineffective ventricular pacing.

• VSR Pace equals the percentage of time the device sensed and paced the ventricle. The ventricular pace is triggered immediately on the ventricular sensed event. The VSR (Ventricular Safety Response) is not considered a ventricular-sensed event because the device paced the ventricle. The VSR is not considered a ventricular-paced event because the patient may not receive the full benefit of a pace when the right ventricle depolarized first.

• VS equals the percentage of time the device sensed in the ventricle.

• CRT Pacing, for devices that include the EffectivCRT Diagnostic feature, equals the percentage of time the device paced in both ventricles or only in the left ventricle.

– Bi-V equals the percentage of time the device paced in the right and left ventricles.

– LV equals the percentage of time the device paced only in the left ventricle.

3.14.2 Graphical data

The rate histograms report the atrial and ventricular event data stored by the device. There are histograms for 3 types of heart rate data: atrial rate, ventricular rate, and ventricular rate during AT/AF. They also report data about the patient’s conduction status, ventricular pacing and sensing, and CRT pacing. The histograms include data from the current and previous collection periods. Data storage for the rate histograms is automatic; no setup is required.

The rate histograms show the percentage of time that the device was pacing and sensing within rate ranges. There are 20 rate ranges that are each 10 bpm in length. Rates slower than 40 bpm are included in the < 40 range; rates faster than 220 bpm are included in the > 220 range.

If AdaptivCRT pacing is programmed to Adaptive Bi-V or to Nonadaptive CRT, 0% is displayed for LV.

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Atrial rate histogram – The atrial rate histogram shows the rate distribution of atrial sensed and paced events (including sensed events that occur during the refractory period). The histogram also indicates if the percentage of atrial senses that may be due to far-field R-wave (FFRW) sensing is 2% or greater. If so, the percentage is reported within 1 of 2 ranges: 2% to 5% of AS may be due to FFRW or >5% of AS may be due to FFRW. Far-field R-wave sensing may be suspected if the intervals between atrial sensed events are irregular.

Ventricular rate histogram – The ventricular rate histogram shows the rate distribution of ventricular sensed and paced events.

Ventricular rate during AT/AF histogram – The ventricular rate during AT/AF histogram shows ventricular sensed and paced events that occurred during detected atrial arrhythmias. Additional information includes the total time in AT/AF5 and the percentage of time the device paced, sensed, or delivered a VSR pace during atrial arrhythmias. This histogram may be used to monitor the effectiveness of ventricular rate control therapy and drug titration.

3.15 Device and lead performance data

The device measures and records battery and lead performance data every day. This information can help you assess the status of the device battery and identify issues with lead position or lead integrity. From the Menu button, you can access device and lead performance data discussed in this section:

• Quick Look screen: Quick Look

• Battery and lead measurements window: DATA > BATTERY AND LEAD MEASUREMENTS

• Lead trends window: DATA > LEAD IMPEDANCE TRENDS

• Capture threshold data: DATA > CAPTURE THRESHOLD TRENDS

The time in AT/AF is calculated from the point of AT/AF Onset. For more information, see Section 5.1, AT/AF detection, page 182.

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3.15.1 Remaining longevity estimate and replacement indicators

The device measures the battery voltage automatically when telemetry is initiated at the start of a session, when a lead impedance test is performed, and every day at 02:15 as part of the automatic daily measurements. The battery voltage measurement at the start of a session is displayed on the BATTERY AND LEAD MEASUREMENTS window. The device uses this data to calculate an estimate of remaining longevity, which is displayed under the REMAINING LONGEVITY label. This estimate is based on the automatic daily measurements of battery voltage, the time since implant, the programmed parameter settings, and the recorded events.

Notes:

• The remaining longevity estimate is updated when parameters are reprogrammed and when the device is interrogated.

• You may see a temporary drop in the displayed battery voltage if high-voltage charging has occurred within the past 7 days.

The calculation of the remaining longevity estimate provides maximum, minimum, and mean values for the amount of time remaining until the device reaches the Recommended Replacement Time (RRT). The mean value is reported under the REMAINING LONGEVITY label as the Estimated at: value. The Maximum: and Minimum: estimate values are 95th percentile values calculated from the distribution of this data. Approximately 95% of devices are expected to reach RRT before the reported maximum value, and approximately 95% of devices are expected to reach RRT after the reported minimum value. When you schedule the replacement of the device, do not consider the estimate of remaining longevity. Instead, schedule device replacement after the RRT condition is reached.

The device reaches RRT 90 days after 3 consecutive daily automatic measurements of ≤ 2.80 V or immediately after 3 consecutive automatic daily measurements of ≤ 2.55 V, whichever comes first. If either event occurs, the implantable device app displays the RRT symbol and the date when the battery reached RRT. Also, the implantable device app displays Replace Device instead of the remaining longevity estimate. If the implantable device app displays the RRT symbol, contact your Medtronic representative and schedule a replacement procedure with your patient.

The expected service life of the device after RRT, defined as the Prolonged Service Period (PSP), is 3 months (90 days).6 After the 90-day PSP has expired, the device reaches End of Service (EOS) and the implantable device app displays the EOS indicator.7

EOS can be indicated before the end of 90 days if the actual battery usage exceeds the expected conditions during the Prolonged Service Period.

EOS can also be indicated if an excessive charge time occurs, or if a rapid current drain condition has developed.

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Warning: Replace the device immediately if the implantable device app displays an EOS indicator. The device may lose the ability to pace, sense, and deliver therapy adequately after the EOS indicator appears.

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3.15.2 Capacitor charging and high-voltage therapy information

On the BATTERY AND LEAD MEASUREMENTS window, the Last Charge and High Voltage Therapy link has information about the last high-voltage charge and the last delivered high-voltage therapy.

• The LAST CHARGE section displays the date, the charge time, and the energy range from the last time the high-voltage capacitors were charged (from any starting energy to any final energy). This information includes periodic charging (if necessary) to condition the battery.

• The LAST HIGH VOLTAGE THERAPY section reports the date, the measured impedance, the delivered energy, the waveform, and the pathway for the last delivered high-voltage therapy.

3.15.3 Sensing Integrity Counter

On the BATTERY AND LEAD MEASUREMENTS screen, the Sensing Integrity Counter link contains information about device problems that are affecting sensing.

When the device senses high-frequency electrical noise, the result is often a large number of ventricular sensed events with intervals near the programmed value for ventricular blanking after a ventricular sense (V. Blank Post VS). The Sensing Integrity Counter records the number of ventricular events with intervals that are within 20 ms of the V. Blank Post VS parameter value. A large number of short ventricular intervals may indicate oversensing, a lead fracture, or a loose setscrew. If the Sensing Integrity Counter reports more than 300 Short V-V Intervals (short ventricular intervals), investigate potential sensing and lead integrity issues. For more information, see Section 3.4, RV Lead Integrity Alert, page 37, and Section 5.9, RV Lead Noise Discrimination, page 221.

3.15.4 Atrial Lead Position Check results

On the BATTERY AND LEAD MEASUREMENTS window, the Atrial Lead Position Check link has information on the most recent check on the position of the atrial lead. This daily check indicates if the position of the atrial lead has moved. If the lead moves, you can program the device to disable atrial therapies accordingly. For more information, see Section 6.1, Atrial therapy scheduling, page 226.

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3.15.5 Lead impedance measurements

On the BATTERY AND LEAD MEASUREMENTS window, the Lead Impedance link provides information on daily pacing and defibrillation impedance for all device leads. The LEAD IMPEDANCE section also has a link (LEAD IMPEDANCE TRENDS) to the LEAD TRENDS window.

Every day at 03:00, the device automatically measures the lead impedance on each implanted lead, using subthreshold electrical pulses. These pulses are synchronized to sensed or paced events and do not capture the heart.

The LEAD IMPEDANCE section provides the daily automatic measurements of lead impedance for all leads.

The LEAD TRENDS window includes a pulldown menu with links to a pacing impedance graph for each lead, and defibrillation impedance graphs for the RV defibrillation lead and the SVC defibrillation lead. These graphs show up to 15 of the most recent measurements and up to 60 weekly summary measurements, showing minimum, maximum, and average values for each week. Significant or sudden changes in lead impedance can indicate a problem with the lead.

If the device is unable to take automatic measurements of lead impedance, gaps are shown in the trend graph.

Note: The RV defibrillation lead impedance, labeled as Defib Impedance, is measured and displayed for the currently programmed defibrillation pathway only. Reprogramming the Active Can/SVC Coil parameter changes the electrodes included in the defibrillation pathway and affects which of the collected measurements are displayed in the Defib Impedance trend graphs.

3.15.6 Sensing amplitude measurements

On the BATTERY AND LEAD MEASUREMENTS window, the Sensing link provides information on daily P-Wave and R-Wave amplitude measurements and amplitude trends.

Every day at 02:15, the device begins to measure the amplitude of intrinsic sensed events. The device attempts to measure the amplitude of 9 normal intrinsic sensed events, and then records the median value from those events. If the device has not collected 9 amplitude measurements by 24:00, no measurement is recorded. The sensing amplitude trend graph shows a gap for that day.

The daily automatic sensing amplitude measurements are displayed on the Lead Trends screen, which plots the data as a graph. The graph displays up to 15 of the most recent measurements and up to 60 weekly summary measurements (showing minimum, maximum, and average values for each week). Significant or sudden changes in sensing amplitude may indicate a problem with a lead.

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Note: The sensing amplitude trend data is intended to show changes in sensing amplitude measurements that may be used to assess lead integrity. The adequacy of the ventricular sensing safety margin cannot be determined by the R-wave trend measurement and should be based on VF induction testing.

Note: Ventricular sensed events are not common during CRT pacing, so it may be difficult for the device to collect daily R-wave amplitude measurements. However, if the LV Capture Management feature is programmed to Adaptive or Monitor, the device also performs R-wave measurements during the pacing threshold search operation. If fewer than 9 R-wave measurements are collected during a day, the device uses the R-wave measurements collected during the pacing threshold search.

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3.15.7 Capture threshold measurements

If the Capture Management feature is programmed to Adaptive or Monitor, the device automatically performs daily pacing threshold searches and records the results in the capture threshold trends data. For more information, see Section 4.8, Capture Management, page 122.

The results of the daily pacing threshold measurements are displayed in the Capture Threshold graph of the LEAD TRENDS window. The graph displays up to 15 of the most recent measurements and up to 60 weekly summary measurements, showing minimum, maximum, and average values for each week. The LV Capture Threshold trend graph includes annotations for any of the following parameter changes during the reporting period:

• LV Pulse Width programmed to a new value

• LV Pace Polarity programmed to a new value

• LV Pace Polarity automatically switched to a new value by AdaptivCRT

The Capture Threshold graph also displays programmed values for pacing output and Capture Management parameters, the last measured threshold value, and a link to a detailed view of the last 15 days of threshold measurement data. The details screen shows daily results from the last 15 days of threshold measurements. These results include the dates, the times, the threshold measurements, the pacing amplitude values, and the notes describing the results of each pacing threshold search.

The capture threshold trend data provides a way to evaluate Capture Management operation and the appropriateness of the current pacing output values. In addition, sudden or significant changes in the pacing threshold may indicate a problem with a lead.

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3.16 Automatic device status monitoring

The device automatically and continuously monitors internal conditions that affect device operation and require attention. If any conditions occur, a device status indicator is recorded in memory, and a device status indicator warning is displayed on the implantable device app when the device is interrogated. It is also reported in the Quick Look observations.

Warning: If any device status indicators (for example, device reset) are displayed on the implantable device app after interrogating the device, inform a Medtronic representative immediately. If these device status indicators are displayed, therapies may not be available to the patient.

For more information about responding to device status indicator warnings, refer to the implantable device app help.

3.16.1 Operation of automatic device status monitoring

The device monitors and records device status indicators for the following conditions:

• Charge circuit timeout

• Charge circuit inactive

• Device reset

• AT/AF therapies disabled

3.16.1.1 Charge circuit timeout

The charge circuit timeout status indicator is labeled WARNING – CHARGE CIRCUIT TIMEOUT. This status indicator indicates that the device charging period has exceeded 27 s. The charge circuit is still active, but the charge time is too long.

Warning: Contact a Medtronic representative and replace the device immediately if the implantable device app displays a Charge Circuit Timeout message. If this message is displayed, high-voltage therapies are not available for the patient.

3.16.1.2 Charge circuit inactive

The charge circuit inactive status indicator is labeled WARNING – CHARGE CIRCUIT INACTIVE. This status indicator indicates that 3 consecutive charging periods have each exceeded 36 s. The charge circuit is inactive. All automatic therapy functions, EP study functions, and manual system tests are disabled, except for Emergency VVI pacing.

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Warning: Contact a Medtronic representative and replace the device immediately if the implantable device app displays a charge circuit inactive message. If this message is displayed, high-voltage therapies are not available for the patient.

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3.16.1.3 Device reset

The device reset status indicator is labeled WARNING – DEVICE RESET. A device reset is a safety feature that can automatically change parameter values or clear diagnostic data in response to a problem with device memory. There are 2 types of device reset: partial and full. A partial reset clears some or all of the diagnostic data, but the programmed parameters are not affected. A full reset clears all diagnostic data and changes programmed parameters to default reset values. These parameters provide basic device functionality and are considered safe for the majority of patients. For more information about the default reset values for a device model, refer to the parameter tables in the device manual for that model.

The device records a device status indicator when a device reset occurs that requires attention. The device status indicator warning describes how data was affected by the reset. Read the message accompanying the indicator and follow the screen instructions carefully.

Warning: Device reset can be caused by exposure to temperatures below –18°C or strong electromagnetic fields. Advise patients to avoid strong electromagnetic fields. Observe temperature storage limits to avoid exposure of the device to cold temperatures. If a partial reset occurs, pacing resumes in the programmed mode with many of the programmed settings retained. If a full reset occurs, the device operates in VVI mode at 65 bpm. Device reset is indicated by a warning message that is displayed immediately upon interrogation. To restore the device to its previous operation, it must be reprogrammed. Inform a Medtronic representative if your patient’s device has reset.

Note: If a device reset occurs while the MRI SureScan feature is programmed to On, the operation of the MRI SureScan feature is maintained.

For information about responding to the device status indicator warning for device reset, refer to the implantable device app help.

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3.16.1.4 AT/AF therapies disabled

An AT/AF therapies disabled status indicator is labeled AT/AF THERAPIES DISABLED. Atrial therapies can be disabled for the following reasons:

• A ventricular episode was detected following delivery of an automatic atrial therapy before either redetection of AT/AF or termination of AT/AF. Atrial therapy is disabled if it appears that an atrial therapy has initiated a ventricular arrhythmia.

• The Atrial Lead Position Check failed.

• The device detected an accelerated ventricular rate during ATP therapy.

For more information, see Section 6.1, Atrial therapy scheduling, page 226.

3.17 EffectivCRT Diagnostic

Optimal CRT therapy requires a high percentage of effective biventricular pacing or LV pacing. However, device counters that indicate the percentage of biventricular pacing or LV pacing do not indicate whether the pacing was effective – that is, whether it successfully captured the heart. Ineffective CRT pacing can be caused by several factors, such as the presence of AT/AF, AV intervals that are too long, inadequate LV pacing output, delayed LV activation, LV/RV electrode proximity, or atrial or right ventricular undersensing.

The EffectivCRT Diagnostic feature determines the percentage of effective CRT pacing. It provides data about the effectiveness of CRT pacing on the Quick Look screen, and in RATE HISTOGRAMS, Cardiac Compass TRENDS, and EffectivCRT EPISODES.

3.17.1 Operation of EffectivCRT Diagnostic

The EffectivCRT Diagnostic feature determines the percentage of effective CRT pacing by evaluating the morphology of the LV pacing cathode to RVcoil EGM. EffectivCRT Diagnostic data collection is automatic; no setup is required. However, data collection occurs only when all of the following conditions are met:

• The EffectivCRT device check, which evaluates the ability of the device to detect effective CRT pacing under ideal conditions, was successful at least once since implant. The device check is run 30 min after implant and then daily at 01:00.

• LV Amplitude is less than 8.00 V.

• V. Pacing is LV→RV or LV, or the AdaptivCRT algorithm is enabled.

• LV Amplitude was not increased and LV Pace Polarity or LV Pulse Width was not changed since the last successful EffectivCRT daily device check.

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If the above conditions are not met, data is not collected. Data collection begins once the conditions are met following the next EffectivCRT daily device check.

When the data collection conditions are met, the EffectivCRT Diagnostic feature analyzes 100 consecutive ventricular events every hour and determines the percentage of effective CRT pacing.

Notes:

• Ventricular Safety Pacing (VSP) and Ventricular Sense Response (VSR) paces are not evaluated by the EffectivCRT Diagnostic feature.

• For devices with the MPP feature, if the MPP parameter is programmed to On, the EffectivCRT Diagnostic feature evaluates the capture performance of only the first LV pacing vector.

When the EffectivCRT Diagnostic is collecting data, the device switches the EGM3 source to the LV pacing cathode to RVcoil. When a dual cathode LV pacing vector is selected, the device switches the EGM3 source to the more distal LV pacing cathode to RVcoil.

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3.17.2 Viewing EffectivCRT Diagnostic data on the Quick Look screen

The Quick Look screen displays the percentage of effective CRT pacing and, when applicable, observations about the effectiveness of CRT pacing. To access the Quick Look screen, tap Quick Look from the Menu button. For more information, see Section 3.1, Quick Look summary data, page 23.

3.17.3 Viewing EffectivCRT Diagnostic data in the rate histograms

The rate histograms display the percentage of effective and ineffective CRT pacing during AT/AF episodes and outside of AT/AF episodes. To access the rate histograms, tap DATA > RATE HISTOGRAMS. For more information, see Section 3.14, Rate Histograms, page 61.

3.17.4 Viewing EffectivCRT Diagnostic data on Cardiac Compass Trends

Cardiac Compass TRENDS displays the percentage of ventricular pacing per day and the percentage of effective CRT pacing per day. To access Cardiac Compass TRENDS, tap DATA > Cardiac Compass TRENDS. For more information, see Section 3.5, Cardiac Compass Trends, page 41.

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3.17.5 Viewing EffectivCRT Episodes

The EffectivCRT Episodes screen displays data from the 5 most recently recorded episodes of ineffective CRT pacing. Each episode record includes 10 s of the LV pacing cathode to RVcoil EGM with event markers, an indication of which ventricular paces were effective, and an indication of whether AT/AF was present. To access EffectivCRT Episodes data, tap DATA > EffectivCRT EPISODES. For more information, see Section 3.12, EffectivCRT Episodes, page 60.

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4 Pacing features

4.1 Sensing

The device must sense the occurrence of intrinsic cardiac events while avoiding oversensing so that it can deliver therapies appropriately. Effective sensing can reduce the effects of long depolarizations after paced events, oversensing the same event, cross-chamber sensing, sensing far-field R-waves, sensing T-waves, noise, and interference.

Effective sensing is essential for the safe and effective use of the device. The device senses in both the atrium and the right ventricle using the sensing electrodes of the leads implanted in those chambers. You can adjust the sensitivity to intracardiac signals. Each sensitivity setting represents a threshold value that defines the minimum electrical amplitude recognized by the device as a sensed event in the atrium or the right ventricle.

Note: Selecting a higher value for the sensing threshold reduces the sensitivity to lower amplitude signals.

Programmable blanking periods and refractory periods help to screen out extraneous sensing or to prevent the device from responding to it. Blanking periods follow pacing pulses, sensed events, and shocks. Sensing is inhibited during blanking periods. Refractory periods follow pacing pulses and sensed events. The device is able to sense events that occur during refractory periods, but it marks them as refractory events. Refractory events generally have no effect on the timing of subsequent pacing events, but they are used by the tachyarrhythmia detection features.

The sensing polarity is bipolar in the atrium and either bipolar or tip-to-coil in the right ventricle. The device can use either a true bipolar lead or an integrated bipolar lead for right ventricular sensing. With a true bipolar lead, right ventricular sensing can occur between the RV tip and RV ring electrodes (bipolar), or between the RV tip and RV coil electrodes (see Figure 9). The sensing vector is programmable via the RV Sense Polarity parameter. With an integrated bipolar lead, right ventricular sensing occurs between the RV tip and RV coil electrodes. In this case, the RV Sense Polarity parameter has no effect on the sensing vector. The sensing and blanking functions are identical in these lead configurations.

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Figure 9. Ventricular sensing with a true bipolar or an integrated bipolar lead

1 Sensing with a true bipolar lead and RV Sense Polarity programmed to Bipolar 2 Sensing with a true bipolar lead and RV Sense Polarity programmed to Tip to Coil 3 Sensing with an integrated bipolar lead and RV Sense Polarity programmed to either Bipolar or

Tip to Coil

4.1.1 Operation of sensing thresholds

The device automatically adjusts sensing thresholds after certain paced and sensed events to help reduce the oversensing of T-waves, cross-chamber events, and pacing pulses. The threshold adjustment depends on the type of event that precedes the adjustment. During an automatic adjustment, the sensing threshold automatically increases, but it gradually decreases toward the programmed sensitivity value, which is the minimum amplitude that can be sensed. The threshold decrease is intended to be rapid enough to allow subsequent low-amplitude signals to be sensed. Threshold adjustment with nominal settings is shown in Figure 10.

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A. Sense EGM

Markers

V. Sense EGM

Sensing threshold

A S

V S

V P

A P

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Figure 10. Automatic adjustment of sensing thresholds

1 After an atrial sensed event, the device is temporarily less sensitive to atrial events. 2 After a ventricular sensed event, the device is temporarily less sensitive to ventricular events. 3 After an atrial paced event, the device is temporarily less sensitive to ventricular events, but the

sensitivity to atrial events remains the same. 4 After a ventricular paced event, the device is temporarily less sensitive to atrial events. 5 After the post-pace blanking period, the device is temporarily less sensitive to ventricular events.

Note: When high-amplitude sensed events occur, the decrease in sensitivity is limited to prevent undersensing of subsequent intrinsic events.

4.1.2 Operation of blanking periods

Blanking periods follow paced events, sensed events, and shocks. Blanking periods help to prevent the device from sensing pacing pulses, cardioversion and defibrillation pulses, post-pacing depolarization, T-waves, and oversensing of the same event. The blanking periods after paced events are longer than or equal to those after sensed events to avoid sensing the atrial and ventricular depolarizations.

Note: During biventricular pacing, blanking duration is measured from the end of the last ventricular pace.

Programmable parameters determine the lengths of the blanking periods that follow sensed events, paced events, and post-shock paced events.

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Atrial blanking

Ventricular blanking

Markers

A S

A P

B V

V S

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Figure 11. Programmable blanking periods

1 For the duration of this atrial blanking period, which is defined by the A. Blank Post AS parameter,

atrial sensing is disabled after a sensed atrial event. 2 For the duration of this ventricular blanking period, which is defined by the V. Blank Post VS

parameter, ventricular sensing is disabled after a sensed ventricular event. 3 For the duration of this atrial blanking period, which is defined by the A. Blank Post AP parameter,

atrial sensing is disabled after a paced atrial event. 4 For the duration of this ventricular blanking period, which is defined by the V. Blank Post VP

parameter, ventricular sensing is disabled after a paced ventricular event.

The cross-chamber blanking periods listed in Table 8 are nonprogrammable.

Table 8. Cross-chamber blanking periods

Parameter Value

Atrial blanking after a ventricular pacing pulse 30 ms

Ventricular blanking after an atrial pacing pulse 30 ms

The device may lengthen or shorten this value as appropriate after biventricular pacing

pulses or MPP pulses.

If the RV pacing amplitude is programmed at 8 V, this value is 35 ms.

The post-shock blanking periods are also nonprogrammable. After a cardioversion or defibrillation therapy is delivered, the atrial and ventricular blanking is 520 ms.

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4.1.3 Operation of Post-Ventricular Atrial Blanking (PVAB)

The system uses Post-Ventricular Atrial Blanking (PVAB) to eliminate the effect of far-field R-waves. Far-field R-waves are ventricular events that are sensed in the atrium. The PVAB operation is determined by 2 programmable parameters: PVAB Interval and PVAB Method. Atrial events that are sensed during the PVAB interval are used only by tachyarrhythmia detection and do not affect pacing timing. However, changing the PVAB interval determines whether or not events fall in the interval.

The 3 programmable values of PVAB Method are Partial, Partial+, and Absolute. This parameter determines whether atrial events that occur during the PVAB interval are sensed by the device. It also controls how the atrial sensing threshold is adjusted after a ventricular event. Refer to Figure 12 for a comparison of the PVAB methods.

Partial PVAB – When the Partial PVAB method is used, atrial events sensed during the programmed PVAB interval are not used by the bradycardia pacing features but are used by the tachyarrhythmia detection features.

Partial+ PVAB – The Partial+ PVAB method may eliminate the sensing of far-field R-waves more effectively than Partial PVAB. The Partial+ PVAB method operates similarly to the Partial PVAB method. The difference is that after a ventricular event, the atrial sensing threshold is increased for the duration of the programmed PVAB interval. During this time, far-field R-waves are less likely to be sensed. After the PVAB interval, the atrial sensing threshold gradually returns to the programmed level. Extending the PVAB interval may affect intrinsic and far-field R-wave sensing because it changes the time during which the sensing threshold is increased.

Absolute PVAB – When the Absolute PVAB method is used, no atrial events are sensed in the PVAB interval. The Absolute PVAB method is recommended only for addressing complications that are not addressed by the other PVAB methods.

Warning: Programming Absolute as the PVAB Method means that no atrial sensing occurs during the blanking interval. Absolute blanking may reduce the ability to sense AT/AF and reduce the ability to discriminate between VT and SVT. Use the Partial or Partial+ methods unless you are sure that Absolute blanking is appropriate.

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A S

V S

A S

V S

A b

Markers

PVAB Interval

Markers

A. Sense EGM

Sensing threshold

A. Sense EGM

Partial PVAB

Partial+ PVAB

Absolute PVAB

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Figure 12. Comparison of the PVAB methods

1 When the Partial PVAB method is used, if the far-field R-wave exceeds the atrial threshold, an Ab

marker indicates that the event is sensed during the PVAB interval. 2 With the Partial+ PVAB method, after a ventricular sensed or paced event, the atrial sensing

threshold increases, and the device is less sensitive to atrial events. 3 When the Absolute PVAB method is used, an atrial event is blanked in the PVAB interval whether

or not the far-field R-wave exceeds the atrial threshold. 4 Except for the change in the atrial sensing threshold, the Partial+ PVAB and Partial PVAB methods

are similar. With either method, atrial events sensed in the PVAB interval are used by the

tachyarrhythmia detection features.

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Fixed

PVARP

PVAB

A P

B V

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4.1.4 Operation of refractory periods

During a refractory period, the device senses normally but classifies sensed events as refractory and limits its response to these events. The pacing refractory periods prevent inappropriately sensed signals, such as far-field R-waves or electrical noise, from triggering certain pacing timing intervals. Pacing refractory periods do not affect tachyarrhythmia detection.

The availability of refractory periods depends on the programmed pacing mode. The Post Ventricular Atrial Refractory Period (PVARP) is available in dual-chamber pacing modes, and the Atrial Refractory Period is available in atrial pacing modes.

4.1.4.1 Post Ventricular Atrial Refractory Period (PVARP)

PVARP follows a paced, a sensed, or a refractory sensed ventricular event. An atrial event that is sensed during this interval is classified as a refractory event. It does not inhibit a scheduled atrial pace or start a Sensed AV interval. The PVARP setting is only programmable for dual-chamber pacing modes (except DOO mode).

• When the device is operating in the DDDR and DDD modes, the PVARP setting prevents the tracking of retrograde P-waves that could initiate a pacemaker-mediated tachycardia.

• When the device is operating in the DDIR and DDI modes, the PVARP setting prevents the inhibition of atrial pacing based on sensed retrograde P-waves. PVARP should be programmed to a value longer than the VA interval (retrograde) conduction time.

Figure 13. Timing for fixed PVARP

The PVARP parameter may be programmed to Auto instead of a fixed value. Auto PVARP adjusts PVARP in response to changes in the patient’s intrinsic rate or pacing rate. During a Mode Switch episode, the device enables Auto PVARP. For more information, see Section 4.10, Auto PVARP, page 138.

The PVARP setting may be extended by the PVC Response feature or the PMT Intervention feature.

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4.1.4.2 Atrial refractory period

The A. Refractory setting is programmable only for the AAI and AAIR single chamber pacing modes. The atrial refractory period prevents the inhibition of atrial pacing due to sensed far-field R-waves or noise.

4.1.5 Programming sensing

Table 9. How to navigate to sensing parameters from the Menu button

Parameters Path

Atrial Sensitivity RV Sensitivity

PVARP Minimum PVARP

PVAB Interval PVAB Method

A. Blank Post AP A. Blank Post AS

V. Blank Post VP V. Blank Post VS

PARAMETERS > Pacing…

PARAMETERS > Pacing… > PVARP…

PARAMETERS > Pacing… > Blanking…

Caution: Arrhythmia detection or classification is adversely affected if the A. Blank Post AS parameter is programmed to a value that is greater than the nominal setting.

Caution: Arrhythmia detection or classification is adversely affected if the V. Blank Post VS parameter is programmed to a value that is greater than the nominal setting.

Sensing thresholds – The sensing thresholds, set by programming the sensitivity parameters, apply to all features related to sensing, including detection, bradycardia pacing, and the Sensing Test.

Bradycardia pacing and sensing – A combination of high pacing pulse width or high amplitude with a low sensing threshold may cause oversensing across chambers or in the same chamber. Programming a lower pulse width, a lower amplitude, a longer pace blanking, or a higher sensing threshold may eliminate this inappropriate sensing.

Long blanking periods – If you set the blanking periods too long, the device may undersense.

Detection when pacing at high rates – Undersensing may occur if the value for RV Sensitivity is 0.3 mV or higher and the value for Upper Tracking Rate (or Upper Sensor Rate) is greater than 150 bpm.

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High ventricular sensing threshold – Setting RV Sensitivity to a value greater than 0.6 mV is not recommended except for testing purposes. Taking this action may cause undersensing, which may result in the following situations:

• Asynchronous pacing

• Underdetection of tachyarrhythmias

• Delayed or aborted cardioversion therapy

• Delayed defibrillation therapy (when VF confirmation is active)

Sensing during VF – Always verify that the device senses properly during VF. If the device is not sensing or detecting properly, disable detection and therapies and evaluate the system. Monitor the patient for life-threatening tachyarrhythmias until you enable detection and therapies again. You may need to reposition or replace the ventricular sensing lead to achieve proper sensing.

Dual-chamber sensing and bradycardia pacing modes – The device senses in both the atrium and the ventricle at all times, except when the programmed bradycardia pacing mode is DOO, VOO, or AOO. When the pacing mode is programmed to DOO or VOO, there is no sensing in the ventricle. When the pacing mode is programmed to DOO or AOO, there is no sensing in the atrium.

High atrial sensing threshold – If you set the Atrial Sensitivity value too high, the device may not provide reliable sensing of P-waves during AT/AF episodes and sinus rhythm.

Atrial pacing and ventricular sensing – If you program the device to an atrial pacing mode, make sure that it does not sense atrial pacing pulses as ventricular events.

Atrial lead selection – Atrial leads with narrow tip-to-ring spacing (for example, 10 mm) may reduce far-field R-wave sensing.

Repositioning the atrial lead – You may need to reposition or replace the atrial sensing lead if reprogramming the Atrial Sensitivity parameter does not provide reliable atrial sensing during AT/AF episodes and sinus rhythm.

Absolute PVAB – PVAB Method cannot be set to Absolute when the programmed pacing mode is ODO, AAI, or AAIR.

Upper rates and refractory periods – A combination of a high upper sensor rate, a high upper tracking rate, and a long refractory period may result in competitive atrial pacing. For more information, see Section 4.13, Non-Competitive Atrial Pacing, page 147.

Low sensing threshold – If you set a sensitivity parameter to its most sensitive value, the device is more susceptible to electromagnetic interference (EMI), cross-chamber sensing, and oversensing.

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Recommended ventricular sensing threshold – Setting RV Sensitivity to 0.3 mV is recommended to maximize the probability of detecting VF and to limit the possibility of oversensing and cross-chamber sensing.

Recommended atrial sensing threshold – Setting Atrial Sensitivity to 0.3 mV is recommended to optimize the effectiveness of atrial detection and pacing operations while limiting the possibility of oversensing and cross-chamber sensing.

Testing sensitivity after reprogramming – If you change the ventricular sensing threshold or the ventricular sensing polarity, evaluate for proper sensing. If appropriate, test for proper detection by inducing VF and allowing the device to automatically detect and treat the tachyarrhythmia.

Disabling atrial sensitivity – When changing the mode to VVI or VVIR, consider programming Atrial Sensitivity to Off. Disabling atrial sensitivity can preserve battery energy and avoid collection of irrelevant data.

Note: When Atrial Sensitivity is programmed to Off, AT/AF monitoring is disabled.

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4.1.6 Evaluation of sensing

4.1.6.1 Using the Sensing Test to evaluate sensing

The Sensing Test allows you to measure P-wave and R-wave amplitudes. These measurements can be useful for assessing lead integrity and sensing performance. After the Sensing Test is complete, the test results are displayed on the test screen. You can view or save the test results. For more information, see the implantable device app help.

4.1.6.2 Viewing the Sensing Integrity Counter

To access the Sensing Integrity Counter, tap REMAINING LONGEVITY from the Quick Look screen, or tap DATA > BATTERY AND LEAD MEASUREMENTS from the Menu button.

The Sensing Integrity Counter records the number of short ventricular intervals that occur between patient sessions. A large number of short ventricular intervals may indicate oversensing, lead fracture, or a loose setscrew. If the Sensing Integrity Counter reports more than 300 short ventricular intervals, investigate potential sensing and lead integrity issues.

Note: The number of short ventricular intervals is an input to the RV Lead Integrity Alert. For more information, see Section 3.4, RV Lead Integrity Alert, page 37.

4.1.6.3 Viewing P-wave and R-wave amplitude trends

To access P-wave and R-wave amplitude trends, tap DATA > BATTERY AND LEAD MEASUREMENTS > Sensing > P/R WAVE AMPLITUDE TRENDS from the Menu button.

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The daily automatic sensing P-WAVE and R-WAVE amplitude measurements are displayed on the amplitude trends window, which plots the data as a graph. The graph displays up to 15 of the most recent measurements and up to 60 weekly summary measurements, showing minimum, maximum, and average values for each week. You can compare recent amplitude measurements to the trends of daily automatic measurements. Significant or sudden changes in sensing amplitude may indicate a problem with a lead.

Note: The sensing amplitude trend data is intended to show changes in sensing amplitude measurements that may be used to assess lead integrity. The adequacy of the ventricular sensing safety margin cannot be determined by the R-WAVE trend measurement and should be based on VF induction testing.

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4.2 Basic pacing

Patients have a variety of conditions for which pacing therapy may be indicated. These conditions include cardiac asystole, chronic AT/AF, loss of atrioventricular (AV) synchrony, or poor ventricular function due to heart failure.

The system provides dual chamber, single chamber, and cardiac resynchronization (CRT) pacing modes to address different cardiac conditions. Dual chamber pacing restores AV synchrony by sensing and stimulating 2 chambers of the heart, the right atrium and the right ventricle. Single chamber pacing supports patients with infrequent or no occurrences of asystole or patients with chronic AT/AF and for whom dual chamber pacing is not justified. CRT pacing adds a third pacing site in the left ventricle to improve the mechanical contraction of the ventricles to increase the cardiac output of each heartbeat.

4.2.1 Operation of pacing and sensing

The output energy for pacing pulses in each chamber is determined by individually programmed amplitude and pulse width parameters. Although you can program these parameters manually, the Capture Management feature is available to manage pacing output energies in the atrium, the right ventricle, and the left ventricle. For more information, see Section 4.8, Capture Management, page 122.

Pacing polarity is programmable for both the right ventricle and the left ventricle. For more information about LV pacing polarity, see Section 4.4.4, Programming CRT pacing, page 108.

The device provides sensing in both the atrium and the right ventricle. For information about sensing thresholds, lead polarities, blanking periods, and refractory periods, see Section 4.1, Sensing, page 73.

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4.2.2 Operation of dual-chamber pacing

In dual-chamber modes, pacing and sensing occur in the atrium and the ventricle. The dual-chamber pacing modes include DDDR, DDD, DDIR, and DDI. In the DDD mode, pacing occurs at the programmed Lower Rate in the absence of intrinsic atrial activity. In the DDI mode, pacing occurs at the programmed Lower Rate. In the DDDR and DDIR modes, which are rate-responsive, pacing occurs at the sensor rate.

4.2.2.1 AAIR<=>DDDR and AAI<=>DDD modes

For information about the AAIR<=>DDDR and AAI<=>DDD modes (MVP modes), see Section 4.3, Managed Ventricular Pacing (MVP), page 94.

4.2.2.2 DDDR and DDD modes

DDDR and DDD are atrial tracking pacing modes. Atrial tracking means that when the device senses an intrinsic atrial event, it schedules a ventricular-paced event in response (see Figure 14). The delay between the sensed atrial event and the corresponding ventricular-paced event is the Sensed AV (SAV) interval. The delay between the paced atrial event and the corresponding ventricular-paced event is the Paced AV (PAV) interval. If a pacing interval ends before the device senses an atrial event, the device paces the atrium and then schedules a ventricular-paced event to occur at the end of the PAV interval. If a ventricular-sensed event occurs during the SAV interval or the PAV interval, ventricular pacing is inhibited. A sensed atrial event that occurs during the Post Ventricular Atrial Refractory Period (PVARP) is classified as refractory. It does not inhibit atrial pacing, and it is not tracked. For more information, see Section 4.1.4.1, Post Ventricular Atrial Refractory Period (PVARP), page 79.

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PAV PAV SAV PAV PAV

ECG

Markers

AV interval

PVARP

Sensor rate interval

V P

A P

A S

A R

V P

A P

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Figure 14. Operation of dual-chamber pacing in DDDR

1 An atrial-paced event starts a PAV interval. 2 An atrial-sensed event starts an SAV interval. 3 An atrial-sensed event during PVARP is not tracked.

4.2.2.3 DDIR and DDI modes

In the DDIR and DDI modes, sensed atrial events are not tracked. When an atrial event is sensed, atrial pacing is inhibited, but a SAV interval is not started (see Figure 15). Instead, ventricular pacing is delivered at the current pacing rate (for example, at the Lower Rate or sensor rate). If the current pacing interval ends before the device senses an atrial event, the device paces the atrium and then schedules a ventricular-paced event to occur at the end of the PAV interval. If a ventricular-sensed event occurs during the PAV interval, ventricular pacing is inhibited. A sensed atrial event that occurs during PVARP is classified as refractory and does not inhibit atrial pacing. For more information, see Section 4.1.4.1, Post Ventricular Atrial Refractory Period (PVARP), page 79.

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A P

A S

V P

A P

V P

A R

PAV PAV PAV

ECG

Markers

AV interval

PVARP

Sensor interval

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Figure 15. Operation of dual-chamber pacing in DDIR

1 An atrial-paced event starts a PAV interval. 2 An atrial-sensed event inhibits the scheduled atrial-paced event but does not start an SAV interval

(is not tracked).

3 An atrial event that is sensed during PVARP does not inhibit the scheduled atrial-paced event.

4.2.2.4 ODO mode (bradycardia pacing off)

The ODO mode does not deliver ventricular or atrial pacing, regardless of the intrinsic rate. The ODO mode is intended only for those situations in which bradycardia pacing is not necessary.

Dual-chamber sensing, atrial detection, ventricular detection, ATP therapy, defibrillation, and cardioversion continue to operate as programmed when pacing is programmed to the ODO mode.

Caution: The device provides no pacing support when it is programmed to the ODO mode. Use the ODO mode only in clinical situations where bradycardia pacing is not necessary or is detrimental to the patient.

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4.2.2.5 DOO mode

The DOO mode provides AV sequential pacing at the programmed Lower Rate with no inhibition by intrinsic events.

Warning: The device provides no sensing or detection in either chamber when it is programmed to the DOO mode. Use the DOO mode only in situations in which asynchronous pacing is warranted.

To program the device to the DOO mode, VT DETECTION and VF DETECTION must be programmed to Off and AT/AF DETECTION must be programmed to Monitor.

4.2.3 Operation of CRT pacing

CRT pacing allows for pacing in the left ventricle and the right ventricle. Pacing both the right and the left ventricles may improve the mechanical contraction of the ventricles to increase the cardiac output of each heartbeat. For more information, see Section 4.4, CRT pacing, page 101.

4.2.4 Operation of single chamber pacing

Single-chamber pacing modes are used to pace either the atrium or the ventricle.

4.2.4.1 AAIR<=>DDDR and AAI<=>DDD modes

For information about the AAIR<=>DDDR and AAI<=>DDD modes (MVP modes), see Section 4.3, Managed Ventricular Pacing (MVP), page 94.

4.2.4.2 VVIR and VVI modes

In the VVIR and the VVI modes, the ventricle is paced if no intrinsic ventricular events are sensed. Pacing occurs at the programmed Lower Rate in the VVI mode and at the sensor rate in the VVIR mode (see Figure 16). In VVIR and VVI modes, the device continues sensing atrial events for tachyarrhythmia detection purposes.

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A S

V P

A S

V PV

V P

ECG

Markers

Sensor interval

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Figure 16. Operation of single-chamber ventricular pacing in VVIR

1 A ventricular-paced event occurs when no intrinsic ventricular event is sensed.

4.2.4.3 AAIR and AAI modes

In the AAIR mode and the AAI mode, the atrium is paced if no intrinsic atrial events are sensed. Pacing occurs at the programmed Lower Rate in the AAI mode and at the sensor rate in the AAIR mode (see Figure 17).

A sensed event that occurs during the atrial refractory period is classified as refractory and does not inhibit atrial pacing. In the AAIR mode and the AAI mode, the device continues sensing ventricular events for tachyarrhythmia detection purposes. VT/VF detection is available but compromised in the AAIR mode and the AAI mode. Cross-chamber blanking can cause ventricular events to go undetected, and crosstalk can cause false detection.

Warning: Do not use the AAIR mode or the AAI mode in patients with impaired AV nodal conduction because these modes do not provide ventricular support.

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A PA

A P

A S

A P

V S

ECG

Markers

Atrial Refractory Period

Sensor rate interval

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Figure 17. Operation of single-chamber atrial pacing in AAIR

1 An atrial event during the atrial refractory period does not restart the A-A pacing interval.

4.2.4.4 VOO mode

The VOO mode provides ventricular pacing at the programmed Lower Rate with no inhibition by intrinsic ventricular events.

Ventricular detection is not available in the VOO mode, although the device continues to sense in the atrium and monitor for atrial arrhythmias. To program the device to the VOO mode, AT/AF DETECTION must be programmed to Monitor, and VT DETECTION and VF DETECTION must be programmed to Off.

4.2.4.5 AOO mode

The AOO mode provides atrial pacing at the programmed Lower Rate with no inhibition by intrinsic atrial events.

When the device is programmed to the AOO mode, it provides no atrial detection even though it offers ventricular sensing. To program the device to the AOO mode, AT/AF DETECTION must be programmed to Monitor and VT DETECTION and VF DETECTION must be programmed to Off.

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4.2.5 Programming pacing therapies

Table 10. How to navigate to basic pacing parameters from the Menu button

Parameters Path

Mode PARAMETERS

Lower Rate Upper Track

A. Amplitude RV Amplitude

A. Pulse Width RV Pulse Width

A. Pace Polarity RV Pace Polarity

Paced AV Sensed AV

Rate Adaptive AV PARAMETERS > Pacing… > Paced AV…

SAV and PAV intervals – The SAV interval is usually programmed 30 ms to 50 ms shorter than the PAV interval. This programming is done to compensate for the inherent delay between the actual cardiac event in the atrium and when it is detected by the device.

Upper Tracking Rate – When programming higher upper tracking rates, SAV and PVARP should be programmed to appropriate values to assure 1:1 tracking. See Section 4.2.7, Tracking rapid atrial rates, page 91.

Upper rates and refractory periods – A combination of a high Upper Sensor Rate and a long refractory period may result in competitive atrial pacing. See Section 4.2.7. Consider programming Non-Competitive Atrial Pacing (NCAP) to On.

Pacing safety margins – Pacing pulses must be delivered at an adequate safety margin above the stimulation thresholds.

High pacing output levels – The pulse width and amplitude settings affect the longevity of the device, particularly if the patient requires bradycardia pacing therapy most of the time.

Cross-chamber sensing – Pulse width and amplitude settings can affect cross-chamber sensing. If you set the pulse width and amplitude values too high, pacing pulses in one chamber may be sensed in the other chamber, which could cause inappropriate inhibition of pacing.

RV Amplitude and RV Capture Management – If the RV Amplitude value is > 5.0 V, RV Capture Management is inoperable.

PARAMETERS > Pacing… > Amplitude…

PARAMETERS > Pacing… > Pulse Width…

PARAMETERS > Pacing…

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4.2.6 Evaluation of pacing therapies

To verify that the device is pacing appropriately, tap Quick Look and review the % OF TIME (percentage of time) data on the Quick Look screen. The % OF TIME data reports the percentage of time spent in atrial pacing and ventricular pacing since the last session.

For detailed information about viewing and interpreting information available from the Quick Look screen, see Section 3.1, Quick Look summary data, page 23.

4.2.7 Tracking rapid atrial rates

When the device is operating in the DDDR mode or the DDD mode, the device can track atrial rhythms only up to a certain rate. Limitations on atrial tracking include the 2:1 block rate and the programmed Upper Track rate as described in Section 4.2.7.1.

4.2.7.1 2:1 block

2:1 block occurs when the intrinsic atrial interval is so short that every other atrial sensed event occurs during PVARP (see Figure 18). These atrial events do not start an SAV interval and therefore do not result in ventricular paced events. Because only every other atrial sensed event is tracked, the ventricular pacing rate becomes one-half of the atrial rate. 2:1 block can be a desirable means to prevent rapid ventricular pacing rates at the onset of AT/AF. However, 2:1 block during exertion or exercise is normally undesirable because the ventricular pacing rate can suddenly drop to one-half of the atrial rate. The sudden reduction in cardiac output can result in patient symptoms.

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Figure 18. Example of pacing at the 2:1 block rate

1 One of every 2 atrial sensed events occurs during PVARP and is not tracked.

In some cases, the amount of rate drop is less severe because of pacing at the sensor rate (in the DDDR mode) or because of various rate stabilization, smoothing, or overdrive pacing features.

A common method to prevent 2:1 block at elevated exercise rates (for example, above 150 bpm) is to program shorter than nominal values for SAV and PVARP. Use of the Rate Adaptive AV and Auto PVARP features dynamically shortens the operating SAV and PVARP values during exercise. For more information, see Section 4.10, Auto PVARP, page 138. These features can prevent symptomatic 2:1 block during exercise while allowing nominal or longer SAV and PVARP values at resting rates to help prevent rapid ventricular pacing rates during the onset of AT/AF.

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When programming the SAV or PVARP parameters, the implantable device app calculates and displays the 2:1 block rate. When the 2:1 block rate is dynamic due to the Rate Adaptive AV or Auto PVARP features, the implantable device app displays 2:1 block rates at both rest and exercise.

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4.2.7.2 Upper Track rate

The programmable Upper Track rate also places a limit on the fastest ventricular pacing rate during atrial tracking. Typically, the Upper Track rate is programmed to a rate that is below the exercise 2:1 block rate. If not, the 2:1 block rate becomes the absolute limit and the Upper Track rate cannot be achieved.

1:1 atrial tracking can occur for sinus rates at or below the programmed Upper Track rate. As the sinus rate increases beyond the Upper Track rate, the ventricular pacing rate remains at the Upper Track rate, and the observed SAV interval (AS-VP interval) lengthens with each subsequent pacing cycle. Eventually, after several pacing cycles, an atrial sensed event occurs during PVARP and is not tracked, resulting in a dropped beat. This pattern repeats itself as long as the sinus rate remains above the programmed Upper Track rate. The dropped beat occurs less often when the sinus rate is only slightly above the Upper Track rate (for example, every 7 or 8 beats) and more often as the sinus rate exceeds the Upper Track rate by larger amounts (for example, every 3 or 4 beats).

This Upper Track rate behavior is known as pacemaker Wenckebach (see Figure 19). Wenckebach behavior can be further defined by how often the dropped beat occurs, typically as a ratio of the number of atrial sensed events compared to ventricular paced events (for example, 8:7, 7:6, 6:5, or 3:2). Further increases in the atrial rate may eventually reach the 2:1 block rate where the ratio becomes 2:1.

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Figure 19. Example of Wenckebach pacing

1 SAV intervals extend so that ventricular paced events do not violate the Upper Track rate. 2 An atrial event occurs during PVARP and is not tracked. 3 Tracking resumes on subsequent atrial events.

To provide proper tachyarrhythmia detection, the implantable device app forces the various tachyarrhythmia detection rates to be programmed above the programmed Upper Track rate and prevents long blanking periods from being programmed along with high Upper Track rate values.

4.3 Managed Ventricular Pacing (MVP)

Unnecessary right ventricular pacing may be associated with an increased risk of atrial fibrillation, left ventricular dysfunction, and congestive heart failure, especially in patients with intact or intermittent AV conduction.

Sweeney M, Hellkamp A, Ellenbogen K, et al. Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration in a clinical trial of pacemaker therapy for sinus node dysfunction. Circulation. 2003;107:2932-2937.

Nielsen J, Kristensen L, Andersen H, et al. A randomized comparison of atrial and dual-chamber pacing in 177 consecutive patients with sick sinus syndrome: echocardiographic and clinical outcome. J Am Coll Cardiol. 2003;42:614-623.

8,9,10

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Loss of AV conduction

AV conduction resumes

Intact AV

conduction

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The MVP (Managed Ventricular Pacing) feature is an atrial-based pacing mode that is designed to switch to a dual-chamber pacing mode in the presence of AV block. Specifically, the MVP feature provides the following functions:

• AAI(R) mode pacing when AV conduction is intact

• The ability to switch to DDD(R) pacing during AV block

• Periodic conduction checks while operating in the DDD(R) mode with the ability to switch back to the AAI(R) mode when AV conduction resumes

• Backup ventricular support for transient loss of AV conduction

MVP may be an option for patients who do not respond to cardiac resynchronization therapy (CRT) pacing.

4.3.1 Operation of MVP mode

Figure 20. Overview of MVP mode

4.3.1.1 Intact AV conduction

The MVP modes, AAIR<=>DDDR and AAI<=>DDD, provide AAIR mode or AAI mode pacing while monitoring AV conduction. If AV conduction is intact, the device remains in the AAIR mode or the AAI mode. While operating in the AAI mode or the AAIR mode, the parameters associated with single chamber atrial pacing are applicable.

4.3.1.2 Loss of AV conduction

If 2 of the 4 most recent A-A intervals are missing a ventricular event, the device identifies a loss of AV conduction and switches to the DDDR mode or the DDD mode. The device provides backup ventricular pacing in response to dropped ventricular events until the loss of AV conduction is identified.

Andersen H, Nielsen J, Thomsen P, et al. Long-term follow-up of patients from a randomised trial of atrial versus ventricular pacing for sick-sinus syndrome. Lancet. 1997;350:1210-1216.

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Figure 21. Switching from AAIR mode to DDDR mode

1 The device operates in AAIR mode. 2 At the onset of AV block, the device supplies ventricular backup pacing pulses. 3 The device switches to DDDR mode.

4.3.1.3 AV conduction resumes

After switching to the DDDR mode or the DDD mode, the device periodically checks AV conduction for an opportunity to return to the AAIR mode or the AAI mode. The first AV conduction check occurs 1 min after switching to the DDDR mode or the DDD mode. During the conduction check, the device switches to the AAIR or AAI pacing mode for one cycle.

• If the next A-A interval includes a sensed ventricular beat, the conduction check succeeds. The device remains in the AAIR or AAI pacing mode.

• If the next A-A interval does not include a sensed ventricular beat, the conduction check fails and the device switches back to the DDDR mode or the DDD mode. The time between conduction checks doubles (2, 4, 8 … min, up to a maximum of 16 hours) with each failed conduction check.

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Figure 22. Switching from DDDR mode to AAIR mode after AV conduction resumes

1 The device operates in DDDR mode. 2 The device performs an AV conduction check. AV conduction is detected. 3 The device operates in AAIR mode.

4.3.1.4 Complete AV block

For patients with complete AV block, the device operates in the DDDR mode or the DDD mode persistently. Every 16 hours, the device checks for AV conduction, which results in a single dropped ventricular beat.

Figure 23. Remaining in DDDR mode after an AV conduction check

1 The device operates in DDDR mode. 2 The device checks for AV conduction, but conduction is not detected. 3 The device continues to operate in DDDR mode.

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4.3.1.5 Transient loss of conduction

For transient loss of AV conduction, the device remains in the AAIR mode or the AAI mode and provides a backup ventricular pacing pulse in response to an A-A interval that is missing a ventricular sense.

4.3.1.6 Interactions with MVP mode

Mode Switch – Mode Switch and the MVP modes operate together to adjust the pacing

mode according to the patient’s atrial rhythm and AV conduction status.

Figure 24. Operation of MVP mode and Mode Switch

Atrial Refractory Period – When the MVP feature is operating in the AAIR mode or the AAI

mode, the Atrial Refractory Period is not programmable. Instead, it is automatically adjusted according to the current heart rate: 600 ms for rates below 75 bpm and 75% of the ventricular interval for rates at or above 75 bpm.

PVCs and ventricular tachyarrhythmias – When the MVP feature is operating in the AAIR mode or the AAI mode, the device inhibits atrial pacing in response to PVCs, PVC runs, and ventricular tachyarrhythmia episodes. This behavior is intended to prevent unnecessary atrial pacing when the ventricular rate is faster than the pacing rate. It also allows tachyarrhythmia detection features to operate without disruption from blanking periods caused by atrial pacing.

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After cardioversion or defibrillation therapy – After cardioversion or defibrillation therapy, the device operates in the DDDR or DDD mode for 1 min. If an AV conduction check was scheduled to occur during this time, the check is postponed until after 1 min has passed.

CRT – When MVP pacing mode (AAIR<=>DDDR or AAI<=>DDD) is programmed, CRT pacing is disabled. V. Pacing is programmed to RV. The AdaptivCRT and EffectivCRT During AF algorithms are programmed to Off.

4.3.2 Programming MVP mode

Table 11. How to navigate to the MVP pacing modes (AAIR<=>DDDR and AAI<=>DDD)

from the Menu button

Parameter Path

Mode PARAMETERS > Pacing…

V-V interval variations – Depending on the patient’s intrinsic rhythm and conduction, the MVP mode allows V-V interval variations and occasional pauses of up to twice the lower rate interval.

Paced AV and Sensed AV – For MVP modes, it is not necessary to program longer Paced AV and Sensed AV intervals to promote intrinsic AV conduction. Paced AV and Sensed AV intervals apply only when loss of AV conduction is detected.

Lower rate programming – Upon abrupt loss of AV conduction, prior to switching to the DDDR mode or the DDD mode, ventricular pacing support can be as low as one-half the programmed Lower Rate for 2 consecutive intervals. For patients with sinus bradycardia or frequent loss of AV conduction, program the Lower Rate to 50 bpm or higher.

Complete heart block – For patients with complete heart block, the device drops 1 beat every 16 hours (AV conduction check). See Section 4.3.1.4. If this action is undesirable, permanent DDDR or DDD modes may be more appropriate.

Long PR intervals – For patients with long PR intervals, the device remains in the AAIR mode or the AAI mode. Permanent DDDR or DDD modes may be more appropriate for patients with symptomatic first-degree AV block. Alternatively, you can program the Maximum AV Interval Limit parameter, which causes the device to switch to the DDDR mode or the DDD mode if the patient’s PR interval exceeds the programmed limit.

Operation immediately after implant – The device is shipped in the MVP mode, initially operating in the DDD mode. Approximately 30 min after implant, the device checks for AV conduction and switches to the AAIR mode or the AAI mode if the next A-A interval includes a sensed ventricular beat. See Section 4.3.1.3 for more information.

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4.3.3 Evaluation of MVP mode

The following features can help to assess atrial and ventricular pacing and MVP performance:

• The pacing mode indicator near the top of the implantable device app

• The Quick Look screen

• The RATE HISTOGRAMS diagnostic and report

• The Cardiac Compass TRENDS diagnostic and report

• The MVP Mode Switches diagnostic and report

4.3.3.1 Quick Look screen

The Quick Look screen shows the percentages of atrial and ventricular pacing since the last session. The Quick Look screen also indicates whether the device is programmed to an MVP mode. If the present programmed pacing mode is AAIR<=>DDDR or AAI<=>DDD, the message MVP On appears on the Quick Look screen. Otherwise, the screen displays MVP Off.

For detailed information about viewing and interpreting information available from the Quick Look screen, see Section 3.1, Quick Look summary data, page 23.

4.3.3.2 Cardiac Compass Trends

The % Pacing/day trend graph in the Cardiac Compass TRENDS window helps to evaluate the effectiveness of the MVP mode.

To see the % Pacing/day trend graph, tap DATA > Cardiac Compass TRENDS > Quick Look > Cardiac Compass.

The% Pacing/day graph provides a view of pacing over time that can help you identify pacing changes and trends. The graph displays atrial paces and ventricular paces as a percentage of all events. This information can help determine the effect of the MVP mode on ventricular pacing.

4.3.4 MVP Mode Switches diagnostic

To access the MVP Mode Switches diagnostic, tap DATA > MVP MODE SWITCHES.

The MVP Mode Switches diagnostic lists up to 10 of the most recent MVP mode switches to DDD(R). For more information, see Section 3.13, MVP mode switches data, page 61.

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Specifications and Main Features

Frequently Asked Questions

User Manual

1 Introduction

1.1 About the product literature

1.1.1 Product literature

1.1.2 Technical support

1.2 Device features per model

Table 1. Device model features

2 Patient follow-up guidelines

2.1 In-clinic follow-up appointments and remote monitoring

2.1.1 Remote monitoring options

2.1.2 Follow-up process

2.1.3 Reviewing the presenting rhythm

2.1.4 Verifying the status of the implanted system

2.1.4.1 Assessing the battery status

2.1.4.2 Checking lead measurements and trend data

2.1.4.3 Reviewing Quick Look observations about the status of the device, the leads, and the alert events

2.1.5 Verifying the clinical effectiveness of the implanted system

2.1.5.1 Reviewing Quick Look observations about clinical status

2.1.5.2 Assessing the effectiveness of pacing therapy

2.1.5.3 Assessing effective cardiac resynchronization therapy

2.1.5.4 Assessing tachyarrhythmia detection

2.1.5.5 Assessing tachyarrhythmia therapy

2.1.6 Adjusting device parameters

2.1.7 Scheduling an in-clinic follow-up appointment

Table 2. Example: Responses to different kinds of CareLink transmissions

2.2 Suspending and resuming tachyarrhythmia detection

2.2.1 Considerations for suspending detection

2.2.2 How to suspend or resume detection with the implantable device app

2.2.3 How to suspend or resume detection with a magnet

2.3 Optimizing device longevity

2.3.1 Promoting intrinsic AV conduction

2.3.2 Managing pacing outputs

2.3.3 Optimizing tachyarrhythmia therapy settings

2.3.4 Disabling Atrial Sensitivity

2.3.5 Considering how diagnostic features with data storage impact longevity

2.3.6 Extended wireless telemetry session

3 Diagnostic data features

3.1 Quick Look summary data

3.1.1 Quick Look device and lead status information

3.1.2 Quick Look pacing therapy information

3.1.2.1 Quick Look arrhythmia episode information

3.1.2.2 Quick Look observations

3.2 Medtronic CareAlert Monitoring

3.2.1 Operation of Medtronic CareAlert Monitoring

3.2.2 Operation of Medtronic CareAlert events

3.2.2.1 Patient alert process

3.2.2.2 Instructing the patient

3.2.3 Clinical management and system performance event alerts

3.2.3.1 Clinical management event alerts

3.2.3.2 System performance event alerts

3.2.3.3 Non-programmable system performance event alerts

3.2.4 Programming Alerts

3.2.5 Evaluation of alert events

3.3 OptiVol 2.0 Fluid Status Monitoring

3.3.1 Operation of OptiVol 2.0 Fluid Status Monitoring

3.3.1.1 Daily and reference impedances

Figure 1. OptiVol 2.0 Fluid Trends

3.3.2 Programming OptiVol 2.0 Fluid Status Monitoring

Table 5. How to navigate to OptiVol 2.0 parameters from the Menu button

3.3.3 Evaluation of OptiVol 2.0 Fluid Status Monitoring

3.4 RV Lead Integrity Alert

3.4.1 Operation of RV Lead Integrity Alert

Figure 2. Operation of RV Lead Integrity Alert

3.4.1.1 RV Lead Integrity Alert tones and CareAlert notifications

3.4.1.2 Automatic adjustments to tachyarrhythmia detection

3.4.1.3 EGM storage changes

3.4.2 Evaluation of RV Lead Integrity Alert

3.5 Cardiac Compass Trends

3.5.1 Information provided by Cardiac Compass Trends

3.5.1.1 Event information

Figure 3. Event annotations

3.5.1.2 VT/VF information

Figure 4. VT/VF arrhythmia trend graphs

3.5.1.3 AT/AF information

Figure 5. AT/AF arrhythmia trend graphs

3.5.1.4 Pacing and patient activity information

Figure 6. Pacing and rate response trend graphs