Medtronic 8042B Reference Guide

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INSYNC® III

Device Model 8042 Vision® Programmer Software Model 9981

Device Reference Guide

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

InSync III Model 8042

Device Reference Guide

A reference guide for information about the InSync III Model 8042 Device. Refer to the InSync III Model 8042 Device Programming Guide for information on programming this device.

The following list includes trademarks or registered trademarks of Medtronic in the United States and possibly in other countries. All other trademarks are the property of their respective owners.

Auto PVARP, InSync, Marker Channel, Medtronic, Medtronic Vision, Quick Look, Significant Events, Vision.

Required Physician Training 9

How to Use This Guide 9

1 Pacing modes and the mode switch option 13

Pacing Modes 14

Programming Mode Switch 35

2 Programming rate and rate response parameters 39

Programmable Rates 40

Rate Responsive Pacing 44

3 AV intervals, refractory and blanking periods 55

AV Intervals 56

Rate Adaptive AV 58

Blanking Periods 62

Refractory Periods 64

High Rate Atrial Tracking 75

4 Configuring polarity, output, and sensing 79

Polarity and Lead Monitor 80

Ventricular Pacing Configuration 86

Output and Sensitivity 90

5 Special therapy options 95

Non-Competitive Atrial Pacing 96

PMT Intervention 98

PVC Response 100

Ventricular Safety Pacing 103

Sleep Function 105

6 Telemetry and transtelephonic follow-up features 107

Te l e m e t e r e d Da ta 1 0 8

Extended Telemetry 113

Features for Transtelephonic Follow-up 114

7 Miscellaneous operations 117

Magnet Mode Operation 118

InSync III Model 8042 Device Reference Guide

Contents

Temporary Programming 120

Electrical Reset 121

Elective Replacement Indicator (ERI) 122

Emergency Pacing 123

8 Diagnostics 125

Automatic Diagnostic Data Collection 126

About the Data Displays 128

9 Troubleshooting the device system 139

Troubleshooting Strategy 140

Troubleshooting Electrical Problems 141

Troubleshooting Hemodynamic Problems 143

Device Longevity 145

Replacing the Device 146

Patient Information and Service 147

A Device description 151

Basic Description 152

Lead Compatibility 152

Radiopaque Identification Codes 153

Physical Dimensions 153

Connector Dimensions 153

B Preset parameter settings 155

Shipping Settings 156

Nominal Settings 159

Electrical Reset Settings 162

Emergency Settings 165

C Device programming recommendations 167

Device Programming Recommendations 168

V-V Delay Programming Recommendations 172

D Longevity projections, battery information 177

Estimated Longevity Projections 178

Prolonged Service Period 180

Elective Replacement Indicator (ERI) 180

Battery Specifications 181

InSync III Model 8042 Device Reference Guide

E Telemetry and diagnostic values 183

Magnet Mode Operation 184

Telemetry Functions 185

Automatic Diagnostics 188

F Parameter values and restrictions 191

Programmable Modes and Parameters 192

Parameter Programming Restrictions 197

Temporary Parameters 198

G Warnings, precautions, and EMI 199

Warnings 200

Precautions 205

Potential Complications 210

Potential Events 211

Hospital or Medical Environment Interference 211

Home and Job Environment Interference 214

H Clinical Studies 217

Clinical Studies 218

Contents

Index 219

I Glossary 227

InSync III Model 8042 Device Reference Guide

Required Physician Training

In order to implant a Medtronic biventricular pacing system, the physician is required to:

1. Thoroughly read this manual, and all associated device and/or lead technical manuals.

2. Provide a copy of the patient manual to the patient and discuss it with him or her and any other interested parties.

3. Be trained on the following topics:

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Indications for use

■

Device operation to ensure therapy delivery

■

Measuring and managing biventricular thresholds

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Assembly and use of LV lead implant tools

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Placement of the LV lead

■

Patient management and system follow-up

Prior to implanting the system, Medtronic will certify that physicians received training.

Required Physician Training

How to Use This Guide

Information is Contained in Two Guides

Product information about the InSync III Model 8042 and use of the 9790 series programmer is presented in two separate guides:

■

The InSync III Model 8042 Device Reference Guide, which is supplied with the applicable programmer software and contains instructions on how to use the programmer with the InSync III device.

■

This guide, the InSync III Model 8042 Device Reference Guide, which is a supplementary guide that provides detailed information about the InSync III device model.

Note: A small technical manual, which contains information about implantation, is also supplied with each InSync III device.

InSync III Model 8042 Device Reference Guide

How to Use This Guide

About this Guide

This reference guide covers the information listed below. Included are descriptions of how the various device functions operate.

■

The pacing modes, rate response options, special therapy features, telemetry types, and data collection options. In some cases, guidelines are given on how to configure device operation.

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Parameter and data collection capabilities, longevity projections, and mechanical and electrical specifications.

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Troubleshooting information for electrical and hemodynamic problems.

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Warnings, precautions, and potential interference sources.

About the Device Programming Guide

The device programming guide provides the following information.

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How to setup and configure the programmer and access on-line help.

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How to start a patient session, use the various follow-up features during the session, and properly end the session.

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How to view and print the patient’s ECG and EGM waveform traces.

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How to configure the device to collect diagnostic data, and how to retrieve and view this information.

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How to measure stimulation thresholds and sensing levels.

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How to program parameter values and verify rate response parameters settings.

InSync III Model 8042 Device Reference Guide

Understanding device operation

Part I

Pacing modes and the mode

Pacing Modes 14

Programming Mode Switch 35

switch option

Chapter 1

Pacing Modes

Biventricular Pacing

Atrial Pacing Modes

The information in this section provides an introduction to pacing modes as an aid to mode selection. Included are parameter pertinency tables showing which parameters apply to each pacing mode (asynchronous modes are not included) and a description of each of the available modes.

Note: The pacing mode descriptions presented in this section are not affected by the use of biventricular pacing. Ventricular timing is always based on the first ventricular pace. The VP (ventricular pace) markers in the mode timing illustrations can be interpreted as either a single VP or a BV (biventricular pace).

The InSync III Model 8042 provides the option to program atrial pacing modes. Atrial pacing modes, however, do not provide ventricular resynchronization.

Warning: The atrial only pacing modes available with the InSync III device do not provide cardiac resynchronization for heart failure patients.

InSync III Model 8042 Device Reference Guide

NBG Pacing Codes

CHAMBER PACED

V = Ventricle

A = Atrium

D = Dual Chamber

S = Single Chamber

O = None

CHAMBER SENSED

V = Ventricle

A = Atrium

D = Dual Chamber

S = Single Chamber

O = None

MODE OF RESPONSE

T = Triggered

I = Inhibited

D = Double (Both)

O = None

PROGRAMMABLE/ RATE RESPONSE

P = Programmable

M = Multiprogrammable

C = Communicating

R = Rate Responsive

O = None

DDDR

Pacing modes and the mode switch option

Pacing Modes

The pacing modes are defined in the NBG code.1 Each five-letter NBG code describes a specific type of operation for implantable pacing devices. For simplicity, this manual uses only the first three or four letters, such as DDD, DDIR, DVIR. Figure 1-1 describes the first four letters of the NBG code.

These pacing modes are used for conventional pacing. Currently there are no established pacing codes for biventricular pacing.

Figure 1-1. NBG Pacing Codes

Further Information

The mode descriptions in this chapter provide only a basic overview of each mode. For further details on the rate response, timing and therapy capabilities refer to “Programming rate and rate response parameters” on page 39, “AV intervals, refractory and blanking periods” on page 55, and “Special therapy options” on page 95, respectively.

Bernstein A., et al., “The NASPE/BPEG Pacemaker Code,” PACE, 10(4), Jul-Aug 1987. [“NBG” stands for The North American Society of Pacing and Electrophysiology (NASPE) and the British Pacing and Electrophysiology Group (BPEG) Generic. NBG’s five-letter code supersedes the ICHD Code.]

InSync III Model 8042 Device Reference Guide

Chapter 1

Pacing Modes

). Dashes (–) indicate parameters that are

✓

✓ ✓ ✓✓✓✓✓

✓✓ ✓

–

✓✓

–

✓✓ ✓

✓

✓ ✓ ✓✓✓✓✓

✓ ✓ ✓✓✓✓

✓✓ ✓

✓✓✓ ✓ ✓

Pacing Parameter DDDR DDD DDIR DDI DVIR DVI VDD

Modes/Rates

Lower Rate

Table 1-1 and Table 1-2 show which pacing parameters and features are pertinent to each

pacing mode as indicated by check marks (

programmable when Mode Switch is enabled.

Asynchronous modes are not shown. The following parameters, which apply to all modes in the

Tabl e 1-1. Pacing Parameters Pertinent to Dual Chamber Modes (Including VDD)

tables, are also not shown: Pulse Width, Amplitude, Sensitivity, Pace Polarity, and Sense

Polarity.

Mode Pertinency Tables

InSync III Model 8042 Device Reference Guide

Mode Switch

Upper Tracking Rate

Upper Sensor Rate

Rate Response

Ventricular Pacing Configuration

Ventricular Pacing

First Chamber Paced

V-V Pace Delay

Ventricular Sense Response

Maximum Response Rate

A-V IntervalsdPaced AV Interval

Sensed AV Interval

Rate Adaptive AV

Refractory/Blanking Periods

✓✓✓✓ ✓

✓ ✓ ✓✓✓✓✓

✓ ✓ ✓✓✓✓

✓ ✓ ✓✓✓✓✓

✓✓

✓✓ ✓

✓✓✓✓ ✓

Pacing modes and the mode switch option

Pacing Modes

✓ ✓ ✓✓✓✓

Tabl e 1-1. Pacing Parameters Pertinent to Dual Chamber Modes (Including VDD) (continued)

Pacing Parameter DDDR DDD DDIR DDI DVIR DVI VDD

PVARP (including Auto PVARP)

PVAB

Ventricular Refractory

Ventricular Blanking (after AP)

Interventricular Refractory

Additional FeatureseSleep Function

Non-Competitive Atrial Pacing

PMT Intervention

PVC Response

See Chapter 2 for a description of the rate and rate response parameters.bSee Chapter 1 for a description of Mode Switch operation.cSee Chapter 4 for a description of the Ventricular Pacing Configuration parameters.dSee Chapter 3 for a description of these timing parameters.eSee Chapter 5 for a description of these special therapy options.

Ventricular Safety Pacing

✓ ✓ ✓✓✓ ✓ ✓ ✓✓✓

✓✓ ✓✓

Pacing Parameter VVIR VDIR VVI VDI VVT AAIR ADIR AAI ADI AAT

Modes/Rates

Lower Rate

Upper Sensor Rate

Rate Response

Tabl e 1- 2. Pacing Parameters Pertinent to Single Chamber Modes

InSync III Model 8042 Device Reference Guide

Ventricular Pacing Configuration

Chapter 1

Pacing Modes

✓✓

✓ ✓ ✓✓✓

✓✓

✓✓✓✓✓

✓✓✓✓

Pacing Parameter VVIR VDIR VVI VDI VVT AAIR ADIR AAI ADI AAT

Ventricular Pacing (Chamber)

First Chamber Paced

V-V Pace Delay

Ventricular Sense Response

Tabl e 1- 2. Pacing Parameters Pertinent to Single Chamber Modes

InSync III Model 8042 Device Reference Guide

Maximum Response Rate

Refractory/Blanking PeriodscPVAB

✓✓✓✓✓

Ventricular Refractory

Ventricular Blanking (after AP)

✓✓✓✓✓

Interventricular Refractory

Atrial Refractory

✓ ✓ ✓✓✓ ✓ ✓ ✓✓✓

Additional FeaturesdSleep Function

See Chapter 2 for a description of the rate and rate response parameters.bSee Chapter 4 for a description of the Ventricular Pacing Configuration parameters.cSee Chapter 3 for a description of refractory and blanking periods.dSee Chapter 5 for a description of the Sleep function.

Atrial Blanking

Indications and Usage

The Medtronic InSync III Model 8042 is indicated for NYHA Functional Class III and IV patients who remain symptomatic despite stable, optimal medical therapy (as defined in the clinical trials section), and have a left ventricular ejection fraction ≤ 35% and a prolonged QRS duration.

Rate adaptive pacing is provided for those patients developing a bradycardia indication who might benefit from increased pacing rates concurrent with increases in activity.

Dual chamber and atrial tracking modes are indicated for patients who may benefit from maintenance of AV synchrony.

Contraindications

Dual chamber atrial pacing is contraindicated in patients with chronic refractory atrial tachyarrhythmias.

Asynchronous pacing is contraindicated in the presence (or likelihood) of competitive paced and intrinsic rhythms.

Unipolar pacing is contraindicated in patients with an implanted defibrillator (ICD) because it may cause unwanted delivery or inhibition of defibrillator or ICD therapy.

Pacing modes and the mode switch option

Pacing Modes

Clinical Outcomes

Medtronic biventricular pacing systems for cardiac resynchronization therapy have demonstrated the following clinical benefits through prospectively defined clinical studies:

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Improved NYHA functional class

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Improved quality of life

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Improved exercise capacity

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Reduced risk of all cause mortality

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Reduced risk of all cause mortality or unplanned cardiovascular hospitalization

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Reduced risk of all cause mortality or unplanned heart failure hospitalization

See the Medtronic InSync III Model 8042 Implant Manual for details on study design, objectives, and results.

InSync III Model 8042 Device Reference Guide

Chapter 1

Pacing Modes

DDDR Mode

In the DDDR mode, the device tracks the faster of the intrinsic atrial rate or the sensor-indicated rate. If the intrinsic rate is faster, the DDDR mode provides atrial synchronous pacing; otherwise, AV sequential pacing occurs at the sensor-indicated rate.

■

Rate limits for atrial tracking (Upper Tracking Rate)1 and sensor tracking (Upper Sensor Rate) are separately programmable.

■

The AV intervals that follow sensed atrial events (SAV) and paced atrial events (PAV) are separately programmable, and they can be programmed to shorten with increasing rates (Rate Adaptive AV).

■

A nonrefractory sensed event in either chamber inhibits pacing in that chamber. A ventricular nonrefractory sensed event in the VA interval that is not preceded by an atrial sense (AS or AR) is a device-defined PVC, and starts a new VA interval.

This mode may be appropriate for heart failure patients as it provides both AV synchrony and cardiac resynchronization therapy.

Rate responsiveness has not been evaluated in this patient population.

The Total Atrial Refractory Period (TARP) may limit the tracking rate to a lesser value.

InSync III Model 8042 Device Reference Guide

Pacing modes and the mode switch option

Sensor-indicated

Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms PVARP = 280 ms

Sensor-indicated Rate = 90 ppm (667 ms) SAV Interval = 170 ms

Sensor-indicated

Interval

Figure 1-2. Example of DDDR Mode Operation

Pacing Modes

DDD Mode

The DDD mode provides atrial synchronous pacing in the presence of intrinsic atrial activity; otherwise, AV sequential pacing occurs at the Lower Rate.

■

Each atrial paced or nonrefractory atrial sensed event starts an AV interval and a lower rate interval. The AV intervals that follow sensed atrial events (SAV) and paced atrial events (PAV) are separately programmable, and the SAV may be optionally programmed to shorten with increasing rate (Rate Adaptive AV).

■

A ventricular paced event may track atrial sensed events up to the programmed Upper Tracking Rate.

■

A ventricular nonrefractory sensed event in the VA interval that is not preceded by an atrial sense (AS or AR) is a device-defined PVC, and starts a new VA interval.

This mode is appropriate for heart failure patients as it provides both AV synchrony and cardiac resynchronization therapy.

The Total Atrial Refractory Period (TARP) may limit the tracking rate to a lesser value.

InSync III Model 8042 Device Reference Guide

Lower Rate Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

SAV Interval = 170 ms

Chapter 1

Pacing Modes

Figure 1-3. Example of DDD Mode Operation

DDIR Mode

The DDIR mode provides dual chamber, sensor-driven, atrioventricular (AV) sequential pacing for heart rate variation without atrial tracking.

■

Atrial pacing occurs at the sensor-indicated rate, with ventricular pacing at the end of the PAV interval unless inhibited.

■

An atrial event sensed outside the PVARP will inhibit a scheduled atrial stimulus but will not start an AV interval. That is, ventricular paced events after such sensed atrial events occur at the sensor-indicated rate. The following ventriculoatrial (VA) interval may be extended slightly to avoid an increasing atrial paced rate.

■

A ventricular nonrefractory sensed event in the VA interval starts a new VA interval.

DDIR mode should not be permanently programmed in heart failure patients with normal sinus rhythm. The device will switch to DDIR/DDI modes when a mode switch occurs. Mode switch may be appropriate for patients with a history of atrial arrhythmias.

InSync III Model 8042 Device Reference Guide

Pacing modes and the mode switch option

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

Sensor-indicated Rate = 90 ppm (667 ms)

Sensor-indicated

Interval

Sensor-indicated

Interval

Sensor-indicated

Interval

Sensor-indicated

VA Interval

Figure 1-4. Example of DDIR Mode Operation

Pacing Modes

DDI Mode

The DDI mode provides dual chamber atrioventricular (AV) sequential pacing with atrial sensing but without atrial tracking.

■

Atrial pacing occurs at the Lower Rate, with ventricular pacing at the end of the PAV interval unless inhibited.

■

An atrial event sensed outside the PVARP will inhibit a scheduled atrial stimulus but will not start an AV interval. Ventricular paced events after such sensed atrial events occur at the Lower Rate.

■

A ventricular nonrefractory sensed event in the ventriculoatrial (VA) interval starts a new VA interval.

DDI mode should not be permanently programmed in heart failure patients with normal sinus rhythm. The device will switch to DDIR/DDI modes when a mode switch occurs. Mode switch may be appropriate for patients with a history of atrial arrhythmias.

InSync III Model 8042 Device Reference Guide

Lower Rate Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

Lower Rate Interval

Lower Rate

VA Interval

Chapter 1

Pacing Modes

Figure 1-5. Example of DDI Mode Operation

DVIR Mode

The DVIR mode provides AV sequential pacing at the sensor-indicated rate unless inhibited by ventricular sensed events.

■

Atrial pacing occurs at the sensor-indicated rate, with ventricular pacing at the end of the PAV interval unless inhibited.

The DVIR mode ignores intrinsic atrial events. Sensing occurs only in the ventricle. A ventricular nonrefractory sensed event during the ventriculoatrial (VA) interval starts a new VA interval.

DVIR mode is not appropriate for heart failure patients with normal sinus rhythm.

InSync III Model 8042 Device Reference Guide

Pacing modes and the mode switch option

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

Sensor-indicated Rate = 90 ppm (667 ms)

Sensor-indicated

Interval

Sensor-indicated

Interval

Sensor-indicated

VA Interval

Figure 1-6. Example of DVIR Mode Operation

DVI Mode

Pacing Modes

The DVI mode provides dual chamber AV sequential pacing without atrial sensing/tracking.

■

Atrial pacing occurs at the Lower Rate, with ventricular pacing at the end of the PAV interval unless inhibited.

■

Sensing occurs only in the ventricle, and intrinsic atrial events are ignored. A ventricular nonrefractory sensed event during the VA interval starts a new ventriculoatrial (VA) interval.

DVI mode is not appropriate for heart failure patients with normal sinus rhythm.

InSync III Model 8042 Device Reference Guide

Lower Rate Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

Lower Rate

VA I n ter val

Chapter 1

Pacing Modes

Figure 1-7. Example of DVI Mode Operation

VDD Mode

The VDD mode provides atrial synchronous pacing (or VVI pacing at the Lower Rate). The ventricles are paced synchronously up to the programmed Upper Tracking Rate. the atrium and ventricle, but pacing occurs only in the ventricles.

■

Sensing occurs in both

To promote atrial synchronous pacing at slow rates, a sensed atrial event occurring near the end of the Lower Rate interval will be followed by the programmed maximum SAV interval. The result is an extension of the ventricular lower rate.

A ventricular nonrefractory sensed event in the V-V interval that is not preceded by an atrial sense (AS or AR) is a device-defined PVC, and it starts a new V-V interval.

This mode is appropriate for heart failure patients as it provides

InSync III Model 8042 Device Reference Guide

both AV synchrony and cardiac resynchronization therapy.

The Total Atrial Refractory Period (TARP) may limit the tracking rate to a lesser value.

Pacing modes and the mode switch option

Parameters:

Lower Rate = 60 ppm (1000 ms) SAV Interval = 200 ms

Upper Tracking Rate = 120 ppm (500 ms) PVARP = 250 ms

Lower Rate Interval

SAV

Interval

Figure 1-8. Example of VDD Mode Operation

VVIR / VDIR Modes

Pacing Modes

The VVIR mode provides ventricular rate responsive pacing in patients for whom atrial-based pacing is deemed unnecessary or inappropriate. In the absence of sensed events, the ventricles are paced at the sensor-indicated rate.

The VDIR mode operates the same as the VVIR mode except that events sensed in the atrium are recorded by the diagnostics. When used in conjunction with Marker Channel recordings and concurrent ECG, this mode may be used to observe the underlying atrial rhythm without affecting ventricular pacing.

Note: In the VVIR and VDIR modes, ventricular refractory sensed events restart the Upper Sensor Rate interval.

VVIR/VDIR modes are generally not appropriate for heart failure patients with normal sinus rhythm. In these modes, patients may not receive cardiac resynchronization therapy.

InSync III Model 8042 Device Reference Guide

Parameters:

Lower Rate = 60 ppm (1000 ms) Upper Sensor Rate = 120 ppm (500 ms)

Sensor-indicated Rate = 90 ppm (667 ms) Ventricular Refractory Period = 300 ms

Sensor-indicated

Interval

Sensor-indicated

Interval

Sensor-indicated

Interval

Upper Sensor

Rate Interval

Chapter 1

Pacing Modes

Figure 1-9. Example of VVIR Mode Operation

VVI / VDI Modes

The VVI mode provides single chamber inhibited pacing at the programmed Pacing Rate unless inhibited by sensed events. Sensing occurs only in the ventricle.

The VDI mode operates the same as the VVI mode except that events sensed in the atrium are recorded by the diagnostics. When used in conjunction with Marker Channel recordings and

InSync III Model 8042 Device Reference Guide

concurrent ECG, this mode may be used to observe the underlying atrial rhythm without affecting ventricular pacing.

VVI/VDI modes are generally not appropriate for heart failure patients with normal sinus rhythm. In these modes, patients may not receive cardiac resynchronization therapy.

Pacing modes and the mode switch option

Pacing Rate Interval

Parameters:

Pacing Rate = 60 ppm (1000 ms)

Ventricular Refractory Period = 300 ms

Pacing Rate Interval

Figure 1-10. Example of VVI Mode Operation

Other Available Modes

Pacing Modes

Warning: Atrial only pacing modes do not provide cardiac resynchronization.

AAIR / ADIR Modes

The AAIR mode provides atrial-based rate responsive pacing in patients with intact AV conduction. Sensing and pacing occur only in the atrium. In the absence of sensed events, the chamber is paced at the sensor-indicated rate.

The ADIR mode operates the same as the AAIR mode except that events sensed in the ventricle are recorded by the diagnostics. When used in conjunction with Marker Channel recordings and concurrent ECG, this mode may be used to observe the conducted ventricular rhythm without affecting atrial pacing.

Note: In the AAIR and ADIR modes, atrial refractory sensed events do not restart the Upper Sensor Rate interval.

AAIR/ADIR modes are generally not appropriate for heart failure patients with normal sinus rhythm. In these modes, patients may not receive cardiac resynchronization therapy.

InSync III Model 8042 Device Reference Guide

Parameters:

Sensor-indicated Rate = 75 ppm (800 ms)

Upper Sensor Rate = 100 ppm (600 ms)

Sensor-indicated Interval Sensor-indicated Interval

Chapter 1

Pacing Modes

Figure 1-11. Example of AAIR Mode Operation

AAI / ADI Modes

The AAI mode provides single chamber inhibited atrial pacing. Sensing and pacing occur only in the atrium. Pacing occurs at the programmed Pacing Rate unless inhibited by sensed events.

The ADI mode operates the same as the AAI mode except that events sensed in the ventricle are recorded by the diagnostics. When used in conjunction with Marker Channel recordings and concurrent ECG, this mode may be used to observe the conducted ventricular rhythm without affecting atrial pacing.

AAI/ADI modes are generally not appropriate for heart failure patients with normal sinus rhythm. In these modes, patients may not receive cardiac resynchronization therapy.

InSync III Model 8042 Device Reference Guide

Pacing modes and the mode switch option

Pacing Rate Interval

Parameters:

Pacing Rate = 75ppm (800 ms)

Pacing Rate Interval

Figure 1-12. Example of AAI Mode Operation

AAT / VVT Modes

Pacing occurs at the programmed Pacing Rate, but a nonrefractory sensed event triggers an immediate pacing output (rather than inhibiting such output). Except that pacing outputs occur when events are sensed, the triggered modes operate identically to the corresponding inhibited modes.

Pacing Modes

Note: Programmed triggered pacing will not occur faster than 300 ms (200 ppm) from the previous paced event. Temporary programmed triggered pacing is not limited to 300 ms (200 ppm).

AAT/VVT modes are generally not appropriate for heart failure patients with normal sinus rhythm. In these modes, patients may not receive cardiac resynchronization therapy.

InSync III Model 8042 Device Reference Guide

Pacing Rate Interval

Parameters:

Pacing Rate = 60 ppm (1000 ms)

Ventricular Refractory Period = 300 ms

Pacing Rate Interval

Chapter 1

Pacing Modes

Figure 1-13. Example of VVT Mode Operation

DOOR / AOOR / VOOR Modes

InSync III Model 8042 Device Reference Guide

The DOOR, AOOR, and VOOR modes operate as follows:

■

The DOOR mode provides asynchronous AV sequential pacing at the sensor-indicated rate. Intrinsic events are ignored.

■

The AOOR and VOOR modes provide single chamber pacing at the sensor-indicated rate. Intrinsic events are ignored.

In general, these modes should not be used in heart failure patients.

Pacing modes and the mode switch option

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

Sensor-indicated Rate = 90 ppm (667 ms)

Sensor-indicated

Interval

Sensor-indicated

Interval

Sensor-indicated

Interval

Sensor-indicated

Interval

Figure 1-14. Example of DOOR Mode Operation

DOO / AOO / VOO Modes

Pacing Modes

The DOO, AOO, and VOO modes operate as follows:

■

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

■

The AOO and VOO modes provide pacing at the programmed Pacing Rate with no inhibition by intrinsic events in the applicable chamber.

Besides being directly programmable, the DOO mode is the Magnet mode of the corresponding dual chamber modes, except for the VDD mode, which is the VOO mode. AOO and VOO modes are the Magnet modes of the corresponding atrial and ventricular single chamber modes, respectively.

In general, these modes should not be used in heart failure patients.

InSync III Model 8042 Device Reference Guide

Lower Rate Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms

Lower Rate Interval

Chapter 1

Pacing Modes

Figure 1-15. Example of DOO Mode Operation

ODO / OAO / OVO Modes

Warning: Never program these modes for pacemaker-dependent

patients. For such patients, use the programmer’s inhibit function for brief interruption of outputs.

In the ODO, OAO, and OVO modes, sensing occurs in the designated chamber(s). When used in conjunction with Marker Channel telemetry and concurrent ECG, these modes may be used to observe underlying rhythms.

■

Blanking periods in these modes are automatically minimized to maximize the sensing window(s). Thus, Marker Channel telemetry may display sense markers for cardiac events (for example, far-field R waves) that otherwise would not appear due to longer blanking.

■

No timing intervals or refractory periods are used.

These modes should not be permanently programmed for heart failure patients, as no therapy is provided.

InSync III Model 8042 Device Reference Guide

Programming Mode Switch

Overview

Mode Switch is a programmable On or Off feature designed to prevent the tracking of paroxysmal atrial tachycardias in the DDDR, DDD, and VDD modes. Mode Switch has two programmable subordinate parameters, Detect Rate and Detect Duration, that determine how the device defines and detects an atrial tachyarrhythmia.

When the device detects an atrial tachyarrhythmia, it switches from the programmed atrial tracking mode to a non-atrial tracking mode and remains in this mode until the atrial tachyarrhythmia ceases. Whereupon, the device switches back to the atrial tracking mode (see Figure 1-16).

Mode switch should be used only in heart failure patients with a history of atrial tachycardias as it affects other device parameters associated with delivery of cardiac resynchronization.

Figure 1-16. Mode Switching Modes

Pacing modes and the mode switch option

Programming Mode Switch

Atrial Tracking Mode Non-Atrial Tracking Mode

DDDR DDIR

DDD DDIR

VDD VDIR

Note: Mode Switch is not recommended for patients known to have chronic refractory atrial tachyarrhythmias, such as atrial tachycardia, atrial fibrillation, or atrial flutter.

Atrial Tachyarrhythmia Definition and Detection

The device defines and detects an atrial tachyarrhythmia based on the programmed settings of Detect Rate and Detect Duration.

Detect Rate – Any four of the last seven consecutive atrial beats must exceed the Detect Rate to be detected as a tachyarrhythmia. Note that ventricular tracking is limited by the Upper Tracking Rate or the total atrial refractory period, even when the atrial rate rises above the Detect Rate.

InSync III Model 8042 Device Reference Guide

Chapter 1

Programming Mode Switch

Detect Duration – This is the minimum duration (in seconds) that atrial rate must remain above the Detect Rate to be detected as a tachyarrhythmia.

To detect an atrial tachyarrhythmia, the device monitors for rapid A-A intervals. These intervals include all A-A intervals except AS-AP and AR-AP intervals and AP–AR–AP sequences, which are classified as far-field R waves.

If any four of the last seven consecutive A-A intervals are shorter than the programmed Detect Rate interval and Detect Duration is set to 0 (No Delay), detection occurs and mode switching begins. If Detect Duration is greater than 0, the interval detection criteria must be satisfied for the duration before mode switching occurs.

Switching to Non-Atrial Tracking Mode

When an atrial tachyarrhythmia is detected, the device switches to the appropriate non-atrial tracking mode, as shown in Figure 1-16. To avoid an abrupt drop in the ventricular rate, the device smoothly reduces the pacing rate from the atrial synchronous rate to the sensor-indicated rate (or the lower rate if the patient is inactive) over several pacing cycles.

After the rate transition is completed, the device continues sensor-driven pacing in the ventricles, operating in the non-atrial tracking mode until the atrial tachyarrhythmia ceases, as shown in Figure 1-17.

InSync III Model 8042 Device Reference Guide

Pacing modes and the mode switch option

Detect Rate

Upper

Tracking

Rate

DDDR

Mode

Atrial Rate

Ventricular Rate

Sensor Rate

Atrial tachyarrhythmia is detected

Atrial tachyarrhythmia has ceased

V. Rate

Adjust Period

DDIR Mode

V. Rate

Adjust

Period

Atrial

Tracking

Mode

DDDR

Mode

Figure 1-17. DDDR Mode Switching Operation

Switching Back to Atrial Tracking Mode

Programming Mode Switch

Figure 1-17 shows how the device begins to switch back to the atrial tracking mode after it stops detecting the atrial tachyarrhythmia. When the last seven A-A intervals are longer than the upper tracking rate interval or five consecutive atrial paces occur, the device assumes the atrial tachyarrhythmia has ceased.

DDDR and DDD Modes – Abrupt changes in ventricular rate are avoided by smoothly varying the pacing rate until the pacing rate corresponds to the intrinsic atrial rate. Once this occurs, the device switches to the atrial tracking mode.

VDD Mode – The device immediately switches back to the atrial tracking mode.

Mode Switching Interruption

The typical mode switching sequence may be interrupted by either of these two occurrences:

InSync III Model 8042 Device Reference Guide

Chapter 1

Programming Mode Switch

■

The atrial tachyarrhythmia episode ceases before the device completes the rate transition to the appropriate non-atrial tracking mode.

■

The atrial tachyarrhythmia episode ceases briefly but resumes before the atrial tracking mode is restored.

In either case, the device responds by adjusting the rate transition in the appropriate direction. The criteria for switching to the atrial tracking mode are unaffected.

Programming and Operating Restriction

The following restriction applies to the programming and operation of the Mode Switch feature: Detect Rate must be at least 10 ppm greater than the Upper Tracking Rate and the Upper Sensor Rate.

Recording Mode Switch Episode Data

As described in Chapter 8, the implanted InSync III device automatically collects diagnostic data during episodes of high atrial rate. When the Mode Switch feature is enabled, data collection is based on the Mode Switch detection criteria. With the 9790 programmer, you can interrogate and display Atrial High Rate Episodes, which provide information about the episodes of high atrial rate that triggered Mode Switch operation.

InSync III Model 8042 Device Reference Guide

Programming rate and rate

Programmable Rates 40

Rate Responsive Pacing 44

response parameters

Chapter 2

Programmable Rates

About A–A and V–V Timing

This section includes an explanation of A-A and V-V timing and describes the programmable rate parameters: Lower Rate, Upper Tracking Rate, and Upper Sensor Rate.

A–A Timing – In all modes that pace the atrium, the device times from atrial event to atrial event (A-A timing). This timing method mimics a natural sinus rhythm, producing A-A intervals that are nearly equal, except when timing is interrupted by:

■

PACs in the DDDR, DDD, DDIR, and DDI modes,

■

PVCs in the DDDR, DDD, DDIR, and DDI modes (PVC Response operation),

■

A ventricular sensed event during the VA interval in the DVIR and DVI modes, or

■

An atrial refractory sensed event that triggers an NCAP (Non-Competitive Atrial Pacing) extension.

VA intervals vary due to adjustments by A-A timing operations in order to achieve sensor-indicated or lower rate operation in the presence of varying AV conduction.

V–V Timing – In modes that do not pace the atrium (e.g., VDD or VDIR) or single chamber ventricular modes, the device times from ventricular event to ventricular event (V-V timing).

Note: With biventricular pacing, event timing that involves a ventricular pace is always based on the first ventricular stimulus. The timing diagrams in this chapter depict only the first stimulus of a biventricular pacing output.

InSync III Model 8042 Device Reference Guide

Programming rate and rate response parameters

Lower Rate Interval Lower Rate Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) PAV Interval = 200 ms PVARP = 300 ms

SAV Interval = 180 ms Ventricular Refractory Period = 240 ms

Lower Rate

The programmed Lower Rate defines the slowest rate at which pacing occurs during the basic operation of a mode. In rate responsive modes, in the absence of sensor-detected activity, the sensor-indicated rate is equal to the programmed Lower Rate.

Figure 2-1. Example of Lower Rate Operation

Programmable Rates

Operating Lower Rate

Under certain circumstances, the programmed Lower Rate may be overridden by an operating lower rate that is higher or lower than the programmed value. The following rates may become the operating lower rate:

■

Switching from and back to atrial tracking mode (for Mode Switch)

■

Sleep rate (for Sleep function)

■

Threshold margin test rate of 100 ppm

■

Magnet mode rate of 85 ppm

■

Elective replacement indicator rate of 65 ppm

Selecting a Lower Rate

Program the Lower Rate to maintain adequate heart rates during periods of inactivity or during pauses in atrial rhythms in the DDDR, DDD, VDD, AAIR, ADIR, AAI, ADI, VVIR, VDIR, VVI, and VDI modes.

InSync III Model 8042 Device Reference Guide

Upper Tracking Rate

Parameters:

Sensor-indicated R ate =

75 ppm (800 ms)

Upper Tracking Rate =

100 ppm (600 ms)

SAV Interval = 200 ms

Chapter 2

Programmable Rates

Upper Tracking Rate

Note: In the VDD mode, atrial tracking near the Lower Rate may

result in V-V intervals that exceed the Lower Rate interval. This is normal operation.

The programmable Upper Tracking Rate is the maximum rate at which the ventricles may be paced in response to sensed atrial events in the DDDR, DDD, and VDD modes. Sensed atrial events below the Upper Tracking Rate will be tracked at a 1:1 ratio, but sensed events above the Upper Tracking Rate will result in a tracking ratio less than 1:1 (for example, 6:5, 4:3, 3:2, or 2:1 block).

Figure 2-2. Example of Upper Tracking Rate Operation

Upper Tracking Rate usually should be programmed to a value less than the 2:1 block rate. Refer to “High Rate Atrial Tracking” on page 75 for details.

Upper Sensor Rate

In rate responsive modes, the programmable Upper Sensor Rate

InSync III Model 8042 Device Reference Guide

provides the upper limit for the sensor-indicated rate during physical activity, particularly during vigorous exercise. In the DDDR mode, the Upper Sensor Rate may be higher than, lower than, or the same as the Upper Tracking Rate. See “Rate Responsive Pacing” on page 44.

Programming rate and rate response parameters

Programming Considerations

Programming a combination of high Upper Sensor Rate and Upper Tracking Rate and a long refractory period may result in a shorter “sensing window.” Loss of sensing in such cases could result in competitive pacing (unless Non-Competitive Atrial Pacing is programmed On). See “Non-Competitive Atrial Pacing” on page 96 for more information.

Programming the Upper Tracking Rate to a value greater than the Upper Sensor Rate permits the atrial rhythm to be tracked to a rate higher than the sensor-driven rate. Programming the Upper Sensor Rate to a higher rate than the Upper Tracking Rate permits a higher sensor-driven rate than the atrial tracked rate.

The Upper Sensor Rate and/or Upper Tracking Rate must be greater than the Lower Rate.

Possible Atrial Competition at High Rates

At high sensor-driven rates in the DDDR and DDIR modes, sensor-driven pacing may approximate the intrinsic atrial rate, with some intrinsic atrial events falling into the PVARP. This could result in asynchronous pacing with the potential for competitive atrial pacing. Consider the potential for asynchronous pacing at high rates before selecting an Upper Sensor Rate, especially for patients known to be susceptible to induction of atrial tachyarrhythmias. Weigh the benefits of high rate sensor-driven pacing against the potential for competitive pacing.

Programmable Rates

Note: Use of the Rate Adaptive AV feature and automatic PVARP can reduce the likelihood of the type of asynchronous pacing described above. In the DDD and DDDR modes, NCAP can also be considered.

Device Circuit Rate Limit

An internal circuit, independent of the pacing timers, limits single chamber atrial or ventricular pacing rates to 200 ppm for most single component failures. For dual chamber modes, atrial and ventricular rates are limited independently to 200 ppm. This rate limit is automatically disabled during temporary pacing in the AAI, ADI, AAT, and AOO modes and in the VVI, VDI, VVT, and VOO modes (RV only pacing) to allow high rate pacing for diagnostic or therapeutic purposes.

InSync III Model 8042 Device Reference Guide

Chapter 2

Rate Responsive Pacing

Overview

Sensor-Indicated Rate

Activity-based, rate responsive pacing varies the pacing rate in response to the patient’s detected physical activity. The InSync III device provides the following rate responsive pacing modes:

Dual chamber modes: DDDR, DDIR, DVIR, DOOR

Single chamber modes: VVIR, VDIR, VOOR, AAIR, ADIR, AOOR

The rate response features discussed in this section apply to all of these modes. Refer to “Parameter Values and Restrictions” on page E-1 for specific capabilities.

In rate responsive modes, pacing occurs at the sensor-indicated rate unless inhibited by sensed events. The sensor-indicated rate is derived from the output of the activity sensor and the programmed settings of the rate response parameters. Output of the sensor reflects both the frequency and amplitude of physical activity.

■

In dual chamber rate responsive modes, the sensor-indicated interval is the AS-AP or AP-AP interval.

■

In single chamber rate responsive modes, the sensor-indicated interval is the A-A or V-V interval. In these modes, sensor-indicated rate intervals start with a sensed or paced event in the chamber being paced.

InSync III Model 8042 Device Reference Guide

Programming rate and rate response parameters

Sensor-Indicated

Interval

Sensor-Indicated

Interval

Parameters:

Sensor-Indicated Rate = 90 ppm (667 ms)

PAV Interval = 200 ms PVARP = 300 ms

SAV Interval = 190 ms Ventricular Refractory Period = 220 ms

Sensor Sensor Sensor

Figure 2-3. Example of Sensor-Indicated Rate Operation

Rate Responsive Pacing

Effect of Sensor-Indicated Rate on Other Intervals

The sensor-indicated rate is used to determine the values of certain other timing intervals. These intervals are:

■

Rate adaptive paced AV (PAV) interval

■

Auto PVARP in DDIR mode

■

Ventricular interval during Mode switching

InSync III Model 8042 Device Reference Guide

Chapter 2

Rate Responsive Pacing

Rate Response - Parameters and Operation

The following programmable parameters are involved in the set up and operation of rate responsive pacing.

Lower Rate – Defines the slowest rate at which pacing occurs in the absence of a sinus rate or physical activity.

Upper Sensor Rate – Provides the upper limit for the sensor-driven rate during vigorous exercise.

Activity Threshold – Determines the minimum intensity of detected physical activity to which the device responds.

Rate Response Curve – In conjunction with the Lower Rate and Upper Sensor Rate, establishes the steady-state pacing rate for a given level of detected activity.

Activity Acceleration and Activity Deceleration – Control how rapidly the pacing rate changes in response to increased or decreased activity. One programmable Activity Deceleration setting, “Exercise” provides an extended deceleration period following prolonged exercise.

How Activity Threshold Influences Rate

An activity sensor bonded to the device circuitry is deflected by physical motion. This sensor converts detected motion into electrical signals. The programmed Activity Threshold screens out activity signals below the selected setting.

Activity detection varies from patient to patient due to body structure, placement of implanted device, and so forth. Only sensor signals whose amplitude exceeds the programmed Activity Threshold (as shown in Figure 2-4) are used in computing the sensor-indicated rate. The lower the Activity Threshold, the smaller the signal required to influence the sensor-indicated rate.

InSync III Model 8042 Device Reference Guide

Programming rate and rate response parameters

Time

Activity Threshold = Medium/Low

Activity

Sensor

Output

Settings

High

Med/High

Med/Low

Low

Med/Low

Med/High

High

Rate Responsive Pacing

Figure 2-4. Activity Sensor Signal (Threshold Set to Medium/Low)

Evaluating the Activity Threshold Setting

Walking increases the pacing rate; sitting results in pacing at or near the programmed Lower Rate. Use Table 2-1 below as a guide for selecting an appropriate setting.

Tab le 2-1 . Activity Threshold Guidelines

Programmable Settings

Low Responds to most body activity, including

Medium/Low Limited response to minimal exertion;

Medium/High Limited response to moderate body

High Responds to only vigorous body movements

Typical Rate Performance

minimal exertion.

responds to moderate or greater exertion.

movements and exertion.

and exertion.

InSync III Model 8042 Device Reference Guide

Chapter 2

Rate Responsive Pacing

How Rate Response Curve Influences Rate

The Rate Response Curve parameter, in conjunction with the Lower Rate and Upper Sensor Rate, establishes the steady-state pacing rate for a given level of detected activity (indicated by activity signals that exceed Activity Threshold).

■

Basic Operation

The higher Rate Response Curve settings result in a higher sensor-indicated rate for a given level of detected activity, as follows:

■

Ten rate response curves are available, with the most responsive setting (10) providing the greatest beat-to-beat rate change for a given change in detected activity.

In general, more conditioned patients have greater cardiac reserves, and they may require a lower programmed Rate Response Curve setting.

All rate Response curves are linear and extend from the Lower Rate to the Upper Sensor Rate.

The Upper Sensor Rate can be attained with any rate response curve.

When the activity level stabilizes, the sensor-indicated rate will stabilize.

Determining the Steady-State Pacing Rate

For any rate response curve, the steady-state rate corresponding to a given level of activity depends on the Lower Rate (LR) and Upper Sensor Rate (USR).

Figure 2-6 shows the rate response curve for an elderly patient. Figure 2-7 shows the rate response curve for a pediatric patient. For a given rate response curve (for example, curve 7), both patients achieve their Upper Sensor Rates for the same level of sustained sensor-detected activity, but the rates are quite different. Use the programmed rate limits and the Rate Response Curve to match the rate prescription to the patient’s needs.

InSync III Model 8042 Device Reference Guide

Programming rate and rate response parameters

USR

Pacing Rate

(ppm)

Increasing Activity

USR

Pacing Rate (ppm)

Increasing Activity

Rate Responsive Pacing

Figure 2-5. Rate Response Curve Setting for An Elderly Patient

Figure 2-6. Rate Response Curve Setting for a Pediatric Patient

How Activity Acceleration and Deceleration Influence Rate

Activity Acceleration and Activity Deceleration times control how rapidly the pacing rate changes in response to increased or decreased physical activity. One programmable Activity Deceleration setting, “Exercise” provides an extended deceleration period following prolonged exercise.

InSync III Model 8042 Device Reference Guide

Time (Minutes)

Rate Range

Lower

Rate

Upper

Sensor

Rate

Activity Acceleration

Programmable Settings

15 Seconds

30 Seconds

60 Seconds

Chapter 2

Rate Responsive Pacing

Activity Acceleration

Activity Acceleration time is the time required to achieve approximately 90% of the difference between the current rate and a higher steady-state rate consistent with the current level of activity. Figure 2-7 shows a graphic representation of the acceleration curves at the onset of strenuous exercise.

Figure 2-7. Activity Acceleration Curves

Activity Deceleration

Activity Deceleration time is the time required to achieve approximately 90% of the difference between the current rate and a lower steady-state rate consistent with the current level of activity. Figure 2-8 shows a graphic representation of the deceleration curves at an abrupt cessation of strenuous exercise.

InSync III Model 8042 Device Reference Guide

Programming rate and rate response parameters

Time (Minutes)

Rate Range

Lower

Rate

Upper

Sensor

Rate

Activity Deceleration

Programmable Settings

2.5 Minutes

5 Minutes

10 Minutes

Figure 2-8. Activity Deceleration Curves

Rate Responsive Pacing

Exercise Deceleration Option

Programming Activity Deceleration to “Exercise” extends the rate slowing period following an exercise episode to provide up to 20 minutes of rate deceleration. The device uses activity sensor data to detect periods of vigorous, prolonged exercise. At the end of such an exercise period, the device uses a longer deceleration curve for the central portion of the programmed rate range. The actual deceleration rate is determined dynamically based on the intensity and duration of exercise and the new level of activity. Figure 2-9 shows the composite deceleration curve that applies after the abrupt cessation of sustained exercise.

InSync III Model 8042 Device Reference Guide

Time (Minutes)

Rate Range

Lower

Rate

Upper

Sensor

Rate

5 Minute Deceleration Curve

Begins Exercise Deceleration

Ends Exercise

Deceleration

5 Minute

Deceleration

Curve

Chapter 2

Rate Responsive Pacing

Figure 2-9. Exercise Deceleration

Typical Rate Response Settings

Nominal rate response parameter settings are adequate for many patients: Activity Threshold = Medium/Low, Rate Response Curve = 7, Acceleration = 30 seconds, Deceleration = Exercise.

■

For most patients, the device may be programmed to operate at or near the programmed Lower Rate when the patient is lying, sitting, or standing. If the patient has an elevated pacing rate at rest, Activity Threshold may need to be programmed to a higher setting.

■

InSync III Model 8042 Device Reference Guide

When the patient is walking at a moderate pace, the pacing rate will typically reach 90 ppm to 105 ppm. During more vigorous exercise, the pacing rate will typically reach the Upper Sensor Rate. If the patient has minimal rate response during exercise, Activity Threshold may need to be programmed to a lower setting.

■

A simple programmer-assisted exercise test may be used to tailor rate response settings to a patient’s needs.

■

The Rate Histogram diagnostic may be used to validate programmed rate response settings.

Programming rate and rate response parameters

Using the Exercise Test to Adjusting Rate Response

A programmer-assisted Exercise test can be use to evaluate the patient’s rate response and to allow for programming of the following rate response parameters from the Exercise test results screen.

■

The Desired Rate, Lower Rate, and Upper Sensor Rate parameters (the Rate Response Curve parameter is adjusted automatically based on changes to these parameter values).

■

Activity Acceleration and Deceleration parameters.

Refer to the InSync III Model 8042 Device Reference Guide for instructions on using the Exercise test.

Rate Responsive Pacing

InSync III Model 8042 Device Reference Guide

AV intervals, refractory and blanking

periods

AV Intervals 56

Rate Adaptive AV 58

Blanking Periods 62

Refractory Periods 64

High Rate Atrial Tracking 75

PAV

Interval

PAV

Interval

PAV

Chapter 3

AV Intervals

Paced AV Interval (PAV)

In dual chamber modes, the AV intervals determine the time between the occurrence of an atrial event and the scheduled delivery of stimuli to the ventricles. Separate AV intervals for paced and sensed atrial events are available. The lengths of these intervals may be fixed or programmed to be rate adaptive.

PAV follows an atrial pace in the DDDR, DDD, DDIR, DDI, DVIR, DVI, DOOR, and DOO modes. The PAV interval may differ from the programmed value due to one of the following operations:

■

Rate Adaptive AV

■

Ventricular Safety Pacing

■

Non-Competitive Atrial Pacing

Figure 3-1. Example of PAV Interval Operation

InSync III Model 8042 Device Reference Guide

Sensed AV Interval (SAV)

SAV

Interval

SAV

Interval

SAV SAV

SAV follows an atrial sensed event in atrial synchronous pacing modes (DDDR, DDD, and VDD). The SAV interval duration may differ from the programmed value due to one of the following:

■

Rate Adaptive AV

■

Automatic PVARP

■

Upper Tracking Rate

At fast intrinsic atrial rates, the SAV extends as needed to avoid violation of the programmed Upper Tracking Rate or the total atrial refractory period.

Figure 3-2. Example of SAV Interval Operation

AV intervals, refractory and blanking periods

AV Intervals

InSync III Model 8042 Device Reference Guide

Chapter 3

Rate Adaptive AV

Selecting PAV and SAV

Rate Adaptive AV

Overview

When you program AV intervals, the general hemodynamic goal is to assure that, to the extent possible, left-atrial systole is completed before left-ventricular systole begins. To achieve this, the AV interval durations may be adjusted independently of each other.

■

To accommodate the difference in interatrial conduction times, the SAV usually should be programmed to a shorter duration than the PAV, typically 30 to 50 ms shorter. If an SAV greater than the PAV is selected, the programmer notes that this is not usual, but the selected values may be programmed if clinically warranted.

■

When the SAV is longer than the PAV, a V pace following an atrial sense will always occur after the full SAV, even when the sensor-indicated rate or Lower Rate interval expires first.

In the normal heart, AV conduction times tend to shorten as the heart rate increases and lengthen as the heart rate decreases. The Rate Adaptive AV (RAAV) feature, available in the DDDR, DDD, DDIR, DVIR, DOOR, and VDD modes, mimics this physiologic response. When RAAV is programmed On, the device shortens AV intervals for atrial rates within a programmed rate range. This feature provides increased opportunity for atrial sensing, as follows:

■

Shortened SAV intervals increase the tracking range at fast atrial rates by shortening the total atrial refractory period (TARP) and increasing the 2:1 block rate. Refer to “Total Atrial Refractory Period (TARP)” on page 68 and “High Rate Atrial Tracking” on page 75 for more information.

■

Shortened PAV intervals lengthen the atrial sensing window of the VA interval at higher sensor-driven rates.

Note: RAAV will not shorten AV intervals to less than 30 ms.

InSync III Model 8042 Device Reference Guide

Programming Rate Adaptive AV

For RAAV operation, the SAV and PAV are programmed (as applicable) to the values desired for low rates. Additional programmable parameters control how AV intervals are adjusted at higher rates:

Start Rate – RAAV operation of shortening SAV and PAV intervals begins at this rate.

Stop Rate – The shortest SAV and PAV occur at this rate and at all higher rates, up to the upper rate limits.

A minimum value for either SAV or PAV is selectable, depending on the pacing mode:

Minimum Sensed AV Interval – The shortest allowable SAV, used at or above the Stop Rate is programmed in the DDDR, DDD, and VDD modes.

Minimum Paced AV Interval – The shortest allowable PAV, used at or above the Stop Rate is programmed in the DDIR, DVIR, and DOOR modes. In the DDDR mode, the value is automatically determined by the programmer.

AV intervals, refractory and blanking periods

Rate Adaptive AV

Figure 3-4 shows how the SAV and PAV intervals are linearly shortened as the rate increases from below the Start Rate to above the Stop Rate.

InSync III Model 8042 Device Reference Guide

Atrial Rate Increasing by 2 bpm/beat

Time (Seconds)

Rate (bpm)

MAR Intrinsic Rate

Chapter 3

Rate Adaptive AV

Rate Adaptive AV Operation

Shortening of the AV interval(s) occurs when the appropriate rate exceeds the programmed Start Rate, as follows:

SAV – The mean atrial rate determines SAV adjustments. Because of how the mean atrial rate is calculated:

■

SAV adjustments will lag during rapid increases or decreases in intrinsic atrial rates.

■

The SAV is not adjusted for isolated events (PACs).

■

AS–AP or AR–AP intervals may affect the SAV value since these intervals are not used in the mean atrial rate calculation.

PAV – The sensor-indicated rate determines PAV adjustments.

The approximate difference between programmed SAV and PAV is maintained as the SAV and PAV intervals are adjusted.

About Mean Atrial Rate

Mean atrial rate (MAR) is a running average of the atrial rate that is used by the Rate Adaptive AV and automatic PVARP features. The average uses all A–A intervals (except AS-AP or AR-AP intervals). In order to respond quickly to rapidly increasing atrial rates, the average gives preference to shorter A-A intervals over longer intervals when calculating the MAR. Figure 3-3 shows how the MAR tracks an increasing intrinsic atrial rate.

Figure 3-3. Increasing Mean Atrial Rate

InSync III Model 8042 Device Reference Guide

AV intervals, refractory and blanking periods

Rate (ppm)

AV Interval (ms)

Parameters:

Start Rate = 80 ppm Programmed PAV = 200 ms Programmed SAV = 170 ms

Stop Rate = 150 ppm Minimum PAV = 100 ms Minimum SAV = 70 ms

Start Rate Stop Rate

Programmed PAV

Programmed SAV

Minimum SAV

Minimum PAV

Figure 3-4. Rate Adaptive AV Operation (DDDR Mode)

Rate Adaptive AV

Rate Adaptive AV Operation in DDDR and DDD Modes

The DDDR and DDD modes use both the PAV and SAV intervals:

■

DDDR Mode – Both the SAV and PAV may be adjusted.

■

DDD Mode – SAV may be adjusted. The PAV is not adjusted unless mode switch is on. Mode switching to the nonatrial tracking DDIR mode requires the PAV.

InSync III Model 8042 Device Reference Guide

Chapter 3

Blanking Periods

Blanking periods disable sensing for a programmable or nonprogrammable interval. Signals that are blanked may originate in either chamber or from outside sources such as noise from muscle movement.

Figure 3-5. Example of Dual Chamber Blanking Operation

Note: Black bars indicate blanking periods.

1 Nonprogrammable Atrial Blanking

2 Programmable Post-Ventricular Atrial Blanking

3 Programmable Ventricular Blanking

4 Nonprogrammable Ventricular Blanking

Nonprogrammable Blanking Periods

Immediately following a sensed or paced event in either chamber, sensing for that chamber is blanked for a nonprogrammable period that may vary from 50 to 100 ms. The actual duration of the blanking period is determined dynamically by the device, based on the strength and duration of the signal. Dynamic blanking prevents sensing the same signal twice, while minimizing total blanking time.

InSync III Model 8042 Device Reference Guide

Post-Ventricular Atrial Blanking

The programmable Post-Ventricular Atrial Blanking (PVAB) period, used in the DDDR, DDD, DDIR, DDI, VDD, VDIR, and VDI modes, prevents sensing of ventricular paced events or far-field R waves on the atrial lead. Any ventricular event (paced or sensed) starts the PVAB, which is also the first portion of the Post-Ventricular Atrial Refractory period (PVARP). PVAB is limited to values equal to or less than the programmed PVARP, except in the VDIR and VDI modes in which PVARP does not apply.

Note: PVAB is set to a value less than or equal to PVARP.

Ventricular Blanking

The programmable Ventricular Blanking period, which follows an atrial pacing stimulus in the DDDR, DDD, DDIR, DDI, DVIR, and DVI modes, prevents ventricular inhibition or ventricular safety pacing due to sensing of the atrial stimulus on the ventricular lead (crosstalk). The Ventricular Blanking period also applies to the ADIR and ADI modes to prevent sensing of the atrial stimulation.

■

Long blanking periods (36 ms or greater) increase the possibility of unsensed ventricular events.

■

Long blanking periods used in conjunction with long PAV intervals (250 ms or greater) may result in pacing into the T wave when intrinsic ventricular events are blanked and not sensed. PAV values (200 ms or less) should reduce the possibility of T wave pacing.

AV intervals, refractory and blanking periods

Blanking Periods

Single Chamber Atrial Blanking

The programmable single chamber atrial blanking period, used in the AAIR, ADIR, AAI, ADI, and AAT mode, prevents sensing of far-field R waves. It is started by a paced, sensed, or refractory sensed atrial event.

Note: Atrial Blanking must be programmed at least 50 ms less than the Atrial Refractory Period.

InSync III Model 8042 Device Reference Guide

Chapter 3

Refractory Periods

Overview

A refractory period is an interval during which an intrinsic event sensed on a particular lead channel cannot start certain timing intervals. Each refractory period begins with a blanking period, during which no sensing occurs. During the unblanked portion of a refractory period, sensing occurs, but sensed events may not directly affect timing operations. Refractory periods are intended to prevent certain timing intervals from being started by inappropriate signals such as retrograde P waves, far-field R waves, or electrical noise.

Though they may not start timing intervals, refractory sensed events are monitored by the device, and they affect the operation of PVC Response, Mode Switch, Rate Adaptive AV operation, automatic PVARP, Non-Competitive Atrial Pacing, and other features for which the periodicity or number of sensed events are pertinent. Refractory sensed events are included on Marker Channel recordings.

Post-Ventricular Atrial Refractory Period

The Post-Ventricular Atrial Refractory Period (PVARP) follows a paced, sensed, or refractory sensed ventricular event in the DDDR, DDD, DDIR, DDI, and VDD modes. It is intended primarily to prevent the sensing of retrograde P waves that might promote Pacemaker-Mediated Tachycardias (PMTs) in atrial tracking modes. In the DDIR and DDI modes, PVARP prevents atrial inhibition from retrograde P waves.

InSync III Model 8042 Device Reference Guide

AV intervals, refractory and blanking periods

PVARP

Refractory Periods

The first portion of the PVARP is the programmable Post-Ventricular Atrial Blanking period (PVAB). During the remainder of the PVARP, intrinsic atrial events may be sensed as refractory sensed events (AR) and identified on Marker Channel recordings, but they do not affect stimulus timing.

■

In the DDDR, DDD, and VDD modes, an SAV is not started.

■

In the DDDR, DDD, DDIR, and DDI modes, the scheduled atrial pace is not inhibited.

Figure 3-6. Example of PVARP Operation

The duration of the PVARP may be selected as follows:

■

The PVARP should be programmed to a value greater than the patient’s ventriculoatrial (VA) retrograde time when retrograde conduction is present.

■

Excessively long PVARPs may induce 2:1 block at high intrinsic rates in atrial tracking modes (DDDR, DDD, and VDD).

■

To reduce the 2:1 block point, PVARP can be set to “auto.” When it is programmed to “auto,” the device varies the PVARP based on whether the operating mode is a tracking or nontracking mode.

InSync III Model 8042 Device Reference Guide

Chapter 3

Refractory Periods

Auto PVARP (Tracking Modes)

When the device is operating in a tracking mode (DDDR, DDD, or VDD), Auto PVARP varies based on the mean atrial rate (see “About Mean Atrial Rate” on page 60). To facilitate tracking of fast atrial rates, Auto PVARP maintains a 2:1 block rate at least 30 ppm greater than the mean atrial rate. The device automatically adjusts the PVARP to produce a Total Atrial Refractory Period equal to the target 2:1 block rate. Refer to “Total Atrial Refractory Period (TARP)” on page 68.

For these modes, Auto PVARP is intended to do the following:

■

Provide a higher 2:1 block rate by shortening the PVARP at higher tracking rates.

■

Protect against PMTs at lower rates by providing a longer PVARP.

The calculated 2:1 block rate has the following limits:

■

The minimum 2:1 block rate is 100 ppm for Minimum PVARP settings of 150 to 250 ms. If Minimum PVARP is greater than 250 ms, the minimum 2:1 block rate will be less than 100 ppm.

■

The maximum 2:1 block rate is the Upper Tracking Rate plus 35 ppm. If Mode Switch is enabled, the maximum 2:1 block rate is the Detect Rate (only if this rate is less than the Upper Tracking Rate plus 35 ppm).

Figure 3-7 shows how Auto PVARP is equal to Minimum PVARP when tracking occurs at the Upper Tracking Rate and how it is adjusted to a longer value at the Lower Rate.

InSync III Model 8042 Device Reference Guide

AV intervals, refractory and blanking periods

Upper

Tracking

Rate

Lower

Rate

SAV PVARP SAV PVARP

Minimum

PVARP

480 ms

Figure 3-7. Auto PVARP Operation (DDDR Mode)

Refractory Periods

Auto PVARP (Nontracking Modes)

When the device is operating in a nontracking mode (DDIR or DDI), Auto PVARP varies with the sensor-indicated rate in the DDIR mode or the lower rate in the DDI mode. The device automatically adjusts PVARP to maintain a 300-ms sensing window.

For these modes, Auto PVARP is intended to do the following:

■

Promote AV synchrony by preventing inhibition of atrial pacing by an atrial sense early in the VA interval.

■

Reduce the likelihood of competitive atrial pacing at high sensor-indicated rates.

Figure 3-8 shows how Auto PVARP is equal to PVAB when pacing occurs at the Upper Sensor Rate and how it is adjusted to a longer value as pacing slows to the Lower Rate.

InSync III Model 8042 Device Reference Guide

Upper

Sensor

Rate

Lower

Rate

PAV PVARP PAV PVARP

Chapter 3

Refractory Periods

Figure 3-8. Auto PVARP Operation (DDIR Mode)

Total Atrial Refractory Period (TARP)

In dual chamber modes that sense in the atrium, the Total Atrial Refractory Period (TARP) is the sum of two intervals, as follows:

AV Inte r val – The AV interval begins with an atrial event and ends with a ventricular event. The first portion is a nonprogrammable blanking period. Its complete duration is determined as follows:

■

In the DDDR, DDD, and VDD modes, the PAV or SAV interval is the AV interval.

■

In the DDIR and DDI modes, the AV interval starts with the first atrial sensed event in the VA interval or with an atrial pacing stimulus; it ends when the PAV expires, even when ventricular pacing is inhibited.

Post-Ventricular Atrial Refractory Period (PVARP) – For information, refer to“Post-Ventricular Atrial Refractory Period” on page 64.

InSync III Model 8042 Device Reference Guide

Figure 3-9. Total Atrial Refractory Period)

TARP TARP

SAV + PVARP

PVARP PVARPSAVSAV

During atrial tracking, TARP = SAV + PVARP, and its duration determines the rate at which 2:1 block occurs. Refer to “High Rate Atrial Tracking” on page 75 for more information.

Ventricular Refractory Period

AV intervals, refractory and blanking periods

Refractory Periods

The programmable Ventricular Refractory Period (VRP) follows paced, sensed, and refractory sensed ventricular events (including PVCs) in all dual chamber and ventricular modes that sense in the ventricle. The VRP is intended to prevent sensing of the T wave or a PVC. The first portion of the VRP is a nonprogrammable blanking period. A ventricular refractory sensed event affects device timing as follows:

■

Ventricular blanking and refractory periods restart in all modes.

■

In the DDDR, DDD, and VDD modes, the upper tracking rate interval, PVARP, and PVAB also restart.

■

In the VVIR and VDIR modes, the upper sensor rate interval restarts.

Note: In dual chamber modes, the VRP should be programmed shorter than the PVARP.

InSync III Model 8042 Device Reference Guide

VRP

Chapter 3

Refractory Periods

Figure 3-10. Example of Ventricular Refractory Period Operation)

In dual chamber modes, a ventricular refractory sensed event does not affect a scheduled sensor-driven or lower rate atrial output. Thus, a sensor-driven atrial output pulse will initiate a PAV with a ventricular output pulse following, unless inhibited.

Interventricular Refractory Period

The programmable Interventricular Refractory Period can be used to address double counting of ventricular events from the same cardiac depolarization, which can occur when the device is configured to sense on both ventricular leads or to pace on one ventricular lead and sense on the other.

Double counting restarts the PVARP timer. This can impact the ability to maintain 1:1 tracking. An atrial event falling within the extended PVARP results in a refractory sense (AR) that cannot be tracked (Figure 3-11).

InSync III Model 8042 Device Reference Guide

Figure 3-11. Interventricular Refractory Period

Interventricular

Refractory Period Off

Interventricular

Refractory Period On

Interventricular Refractory Period

AV intervals, refractory and blanking periods

Refractory Periods

A ventricular sense occurring within the Interventricular Refractory Period (following a ventricular pace or non-refractory sense) does not reset the timing intervals and allows the next sinus beat to be tracked.

Refer to “Programming Interventricular Refractory Period” on page 83 for additional information.

InSync III Model 8042 Device Reference Guide

Chapter 3

Refractory Periods

Atrial Refractory Period (Single Chamber)

The programmable Atrial Refractory Period (ARP) follows paced, sensed, and refractory sensed atrial events. The ARP is used in the AAIR, ADIR, AAI, ADI, and AAT modes. It is intended to prevent inhibition due to far-field R wave sensing. The first portion of the ARP is a programmable blanking period. The ARP should be programmed to a value long enough (150 ms or greater) to prevent far-field R wave sensing but short enough to ensure atrial sensing up to the programmed Upper Sensor Rate.

Noise Reversion

When sensing occurs during the Atrial Refractory Period (ARP) or Ventricular Refractory Period (VRP), the refractory period (and its blanking period) are restarted. The operation associated with continuous refractory sensing in the ARP or VRP is called noise reversion. Multiple restarts of the ARP or VRP (continuous noise reversion) do not inhibit scheduled pacing. Device behavior during continuous noise reversion is as follows:

■

Pacing occurs at the sensor-indicated rate for all rate responsive modes (except VVIR and VDIR).

■

Pacing occurs at the programmed Lower Rate for all non-rate-responsive modes (including VVIR and VDIR).

On the ECG, noise reversion may be difficult to distinguish from loss of sensing, but Marker Channel recordings will show refractory sense markers when noise reversion occurs.

Note: Atrial sensing during the PVARP, or refractory period following an atrial paced or sensed event in the DDDR, DDD, DDIR, DDI, or VDD modes does not restart the refractory period. An atrial refractory sensed event, however, will start a short blanking period of 50 to 100 ms depending on the signal strength and duration of the atrial event.

InSync III Model 8042 Device Reference Guide

AV intervals, refractory and blanking periods

Sensor-Indicated Interval

Parameters:

Lower Rate = 60 ppm (1000 ms) Upper Sensor Rate = 120 ppm (500 ms)

PAV Interval = 200 ms Ventricular Refractory Period = 240 ms

PVARP = 300 ms PVAB = 200 ms

Sensor Sensor Sensor

Lower Rate

Parameters:

Lower Rate = 60 ppm (1000 ms) Upper Sensor Rate = 120 ppm (500 ms)

Ventricular Refractory Period = 240 ms

Sensor Sensor

Refractory Periods

Figure 3-12. Example of Noise Reversion in DDDR at Sensor-Indicated Rate

Figure 3-13. Example of Noise Reversion in VVIR at Lower Rate

InSync III Model 8042 Device Reference Guide

Chapter 3

Refractory Periods

Preventing Noise Sensing

Noise reversion may be caused by electromagnetic interference (EMI), myopotentials, excessively high output settings, or low sensitivity settings. When it has been identified, noise reversion usually can be reduced or eliminated by one of the following actions:

Spontaneous PVARP Extension

The programmed PVARP duration and the automatic PVARP may be overridden by the PVC Response and PMT Intervention features, as follows:

■

Reprogram sensitivity to a less sensitive setting (higher numerical value).

■

Reprogram sensing polarity to bipolar polarity (if available).

■

Reduce the amplitude and/or pulse width in the same or opposite chamber.

■

Remove patient from EMI environment.

■

When the PVC Response feature is programmed On and a device-defined PVC occurs, the PVARP is forced to 400 ms for one cycle if a lesser value is in effect.

■

When PMT Intervention is programmed On and a device-defined PMT is detected, the PVARP is forced to 400 ms for one cycle after the ninth paced ventricular event of the PMT.

Refer to “PMT Intervention” on page 98 and “PVC Response” on page 100 for further details on the PMT Intervention and PVC Response features and their interactions with PVARP.

InSync III Model 8042 Device Reference Guide

High Rate Atrial Tracking

Overview

In the DDDR, DDD, and VDD modes, the fastest atrial rate the device can track is determined by the total atrial refractory period (TARP), which is the sum of the SAV and the PVARP. Device behavior at high atrial rates in these modes is determined by the relationship between the TARP and the interval corresponding to the Upper Tracking Rate. In the DDDR mode, the interval corresponding to the Upper Sensor Rate also must be considered.

2:1 Block

When the intrinsic atrial interval is shorter than the TARP, some atrial events will fall in the PVARP and not be tracked. At the rate where this first occurs, ventricular tracking occurs only on alternate beats, and 2:1 block ensues. In the DDD and VDD modes, the ventricular pacing rate drops precipitously.

■

When automatic PVARP is selected, the 2:1 block rate may occur at a higher rate during activity due to shortening of the PVARP, thus increasing atrial tracking.

■

When Rate Adaptive AV operation is selected, the SAV shortens at high atrial rates, shortening the TARP and raising the 2:1 block rate.

■

When the 2:1 block rate is less than the Upper Tracking Rate, the Upper Tracking Rate cannot be achieved.

■

In the DDDR mode, pacing at the sensor-indicated rate may prevent a precipitous rate drop at the 2:1 block point when activity is present.

■

For patients with a documented propensity for prolonged or sustained atrial fibrillation or flutter, the clinician can select Upper Tracking Rate, SAV, and PVARP values that induce 2:1 block at a desired rate (2:1 block rate = 60,000/TARP). Alternatives for controlling rates in these patients include use of the Mode Switch feature and DDIR mode pacing.

■

In the DDDR mode, atrial competition may occur if Upper Sensor Rate exceeds the 2:1 block rate.

AV intervals, refractory and blanking periods

High Rate Atrial Tracking

InSync III Model 8042 Device Reference Guide

Upper Tracking

Rate Interval

Parameters:

Sensor-Indicated Rate = 90 ppm (667 ms) PVARP = 300 ms

PAV Interval = 230 ms Upper Tracking Rate = 100 ppm (600 ms)

SAV Interval = 200 ms

Sensor

Upper Tracking

Rate Interval

Upper Tracking

Rate Interval

SAV

Interval

Chapter 3

High Rate Atrial Tracking

Pacemaker Wenckebach

When the 2:1 block rate exceeds the programmed Upper Tracking Rate, pacemaker Wenckebach may occur. When the intrinsic rate exceeds the Upper Tracking Rate, a pacing stimulus at the expiration of the SAV would violate the upper tracking rate. The device therefore extends the SAV until the upper tracking rate interval expires. Subsequent SAVs require greater extension, until an atrial event falls in the PVARP and is not tracked.

■

In the DDDR, DDD, and VDD modes, the result normally is a fixed ratio between atrial and ventricular rates (3:2, 4:3, and so forth).

■

In the DDDR mode, the pacemaker Wenckebach rate may be smoothed by sensor-driven ventricular pacing, thereby overriding the fixed ratio.

The following example shows how pacemaker Wenckebach operation occurs in the DDDR, DDD, or VDD modes.

Figure 3-14. Example of Pacemaker Wenckebach Operation

InSync III Model 8042 Device Reference Guide

AV intervals, refractory and blanking periods

High Rate Operation in the DDDR Mode

Table 3-1 summarizes how the total atrial refractory period (TARP), the Upper Tracking Rate (UTR) interval, and the Upper Sensor Rate (USR) interval may interact at high atrial rates in the DDDR mode.

Tab le 3-1 . Upper Rates Interaction With TARP

Relationship Between TARP and Upper Rate Intervals

TARP > both USR and UTR intervals

Wenckebach

High Rate Atrial Tracking

Achieve

Before 2:1

Block

no no yes

Upper

Tracking

Rate

Potential

Atrial

Competition

USR interval > TARP

no no no

> UTR interval

USR interval > UTR

yes yes no

interval > TARP

UTR interval > both

yes yes yes USR interval and TARP

Unless the Non-Competitive Atrial Pacing is On, see “Non-Competitive Atrial Pacing” on page 96.

InSync III Model 8042 Device Reference Guide

Configuring polarity, output, and

Polarity and Lead Monitor 80

Ventricular Pacing Configuration 86

Output and Sensitivity 90

sensing

Chapter 4

Polarity and Lead Monitor

The InSync III device provides independently programmable pacing polarity and sensing polarity for each ventricle (RV and LV) and the atrium. Each output channel also has its own Lead Monitor, which enables the implanted device to monitor lead integrity. If programmed to do so, Lead Monitor can adapt bipolar pacing and sensing to a unipolar configuration if it detects a lead problem.

Pacing Polarity

The Pace Polarity parameter sets the polarity configuration for delivery of pacing stimuli in each chamber. Programmable Pace Polarity options are as follows:

Chamber Pace Polarity Options

Atrium Bipolar, Unipolar

Right Ventricle (RV) Bipolar, Unipolar

Left Ventricle (LV) Bipolar, LVtip/RVring, Unipolar

Bipolar – With this configuration, which is applicable only to bipolar leads, the lead tip is the active electrode; the lead ring is the common electrode. Bipolar pacing is less likely to produce muscle stimulation, but it produces smaller pacing artifacts on the patient’s ECG. Bipolar is a compatible pacing polarity for patient’s who also have an implanted defibrillator (ICD).

Unipolar – With this configuration, the lead tip is the active electrode; the noninsulated device case is the common electrode. Unipolar pacing produces larger pacing artifacts that aid ECG interpretation. However, it is more likely to cause muscle stimulation at the device implantation site, especially at high pacing amplitudes. Unipolar pacing is contraindicated in patients with an implanted ICD.

LVtip/RVring – This configuration applies only to pacing in the left ventricle. The LV lead tip is the active electrode; the RV lead ring is the common electrode. The LVtip/RVring option is intended for use with a unipolar LV lead to provide a bipolar pacing pathway for compatibility with an implanted ICD or to prevent muscle stimulation at the device implantation site (pocket).

InSync III Model 8042 Device Reference Guide

Configuring polarity, output, and sensing

Polarity and Lead Monitor

Note: When LV Pace Polarity is set to LVtip/RVring and the left ventricle is the first chamber paced, capture of the right ventricle by the RV ring electrode may occur, especially at high outputs. This may result in biventricular pacing with no V-V delay. To restore sequential biventricular pacing with the left ventricle paced first, program LV output to a setting below the RV ring capture threshold or program an alternate setting for LV Pace Polarity.

Pacing with a Shared Electrode and Short V-V Delay

When RV Pace Polarity is set to Bipolar, and LV Pace Polarity is set to LVtip/RVring, the RV lead ring serves as a shared common electrode for both RV and LV outputs. If a V-V Delay of 20 ms or less is used for biventricular pacing with this polarity configuration, polarization at the RV ring electrode can reduce amplitude of the ventricular stimuli by up to 0.5 V.

This interaction should be considered during measurement of ventricular stimulation thresholds and can be mitigated by increasing ventricular amplitude by 0.5 V. Amplitude reduction is not present with V-V Delay settings greater than 20 ms or with other Pace Polarity settings.

Muscle Stimulation with Unipolar Pacing

Under certain circumstances such as high output settings, device-induced muscle stimulation may occur at the pocket site. Such muscle stimulation may be minimized or eliminated by programming pulse width or amplitude to a lower setting.

Bipolar or LVtip/RVring Pacing Polarity Confirmation

Before the programmer allows you to program from Unipolar to Bipolar or LVtip/RVring pacing, it verifies the presence of a bipolar current path by testing the impedance for each lead.

■

If the impedance is between 200 ohms and the programmed Lead Monitor maximum impedance level (limit is 4000 ohms), a bipolar path is assumed to be present.

■

If the impedance is outside this range, a unipolar path is assumed to be present. The programmer warns that the test failed, and pacing polarity remains set to unipolar. This interlock feature may be overridden to force lead pacing polarity to bipolar.

InSync III Model 8042 Device Reference Guide

Chapter 4

Polarity and Lead Monitor

Sensing Polarity

Warning: Overriding the bipolar verification prompt with Bipolar or LVtip/RVring polarity when a bipolar path does not exist results in no pacing output.

The Sense Polarity parameter sets the polarity configuration for sensing the atrial and the ventricular depolarization signals. You can configure ventricular sensing to use the right ventricle or both ventricles.

Chamber Sense Polarity Options

Atrium Bipolar, Unipolar

Ventricle RV Bipolar, RV Unipolar, RVtip/LVtip

Warning: Do not program RVtip/LVtip option for Sense Polarity in pacemaker-dependent patients until stability of the left ventricular lead is confirmed. Dislodgement of this lead to a position where the lead senses atrial activity can result in ventricular inhibition. Using RV (right ventricular) sensing in pacemaker-dependent patients for the first 6 months after device implantation will reduce the potential for this to occur.

Bipolar, RV Bipolar – With these configurations, which are applicable only to bipolar leads, the lead tip and the lead ring electrodes are the poles of the sensing circuit. Because bipolar sensing is more localized, it reduces the likelihood of sensing myopotentials and electromagnetic interference. This may permit programming sensitivity to a more sensitive setting.

Unipolar, RV Unipolar – With the unipolar configurations, the lead tip and the noninsulated device case are the sensing electrodes. Unipolar sensing may allow sensing of smaller intrinsic signals than does bipolar sensing and therefore can be selected when intrinsic cardiac signals are difficult to detect. However, oversensing due to myopotentials is more common with unipolar sensing than with bipolar sensing.

InSync III Model 8042 Device Reference Guide

Configuring polarity, output, and sensing

Polarity and Lead Monitor

RVtip/LVtip – This configuration uses the tip of the RV lead and the tip of the LV lead as the two sensing electrodes to provide sensing in both ventricles. This configuration allows the device to sense the first ventricle to depolarize, which may have timing advantages, particularly when the Ventricular Sense Response feature is used. Note the following points regarding use of the RVtip/LVtip configuration:

■

Stability of the left ventricular lead should be confirmed before using the RVtip/LVtip configuration.

■

The RV Sensitivity parameter adjusts sensitivity when the RVtip/LVtip configuration is enabled.

■

The RV EGM Telemetry Mode displays the composite EGM of both ventricles. The LV EGM, Dual VEGM, and A+LV EGM Telemetry Mode options are not available with the RVtip/LVtip configuration.

■

With the RVtip/LVtip sensing configuration, a timing difference between the depolarization of the right and the left ventricles can result in double sensing during a single contraction unless the Interventricular Refractory Period is programmed as described next.

Programming Interventricular Refractory Period

When RVtip/LVtip is chosen as the ventricular sensing polarity configuration, the Interventricular Refractory Period should be used to prevent sensing of the second depolarization signal when the right and left ventricles do not depolarize simultaneously.

A ventricular sense occurring within the Interventricular Refractory Period (following a ventricular pace or non-refractory sense) does not reset timing intervals (see “Interventricular Refractory Period” on page 70).

By setting up the programmer live rhythm display to show an EGM trace of ventricular sensing in both chambers, you can use the Freeze function to measure the delay between depolarizations.

InSync III Model 8042 Device Reference Guide

Chapter 4

Polarity and Lead Monitor

Figure 4-1. RV and LV Depolarization Delay

Interventricular Refractory Period should be programmed to an interval that is at least 30 ms greater than the measured delay between chamber depolarizations. A programming restriction requires that the selected value for Interventricular Refractory Period be at least 60 ms shorter than the Ventricular Refractory Period.

During a patient follow-up session, the ventricular Heart Rate Histogram diagnostic printed report can be used to verify the effectiveness of the programmed Interventricular Refractory Period. The report lists the number of VS-VR sequences counted since the last patient session.

The count for “VS-VR Short” indicates the number of VR senses falling within the Interventricular Refractory Period. Conversely, the count for “VS-VR Long” indicates the number of VR senses falling outside the Interventricular Refractory Period. A high count for the VS-VR Long sequence may indicate the need for a longer Interventricular Refractory Period.

Bipolar Sensing Polarity Confirmation

Before the programmer allows you to program from unipolar to bipolar sensing, it verifies the presence of a bipolar lead by testing the impedance for each lead.

■

If bipolar lead impedance is between 200 ohms and the programmed Lead Monitor maximum impedance level (limit is 4000 ohms), a bipolar lead is assumed to be present.

InSync III Model 8042 Device Reference Guide

Lead Monitor

Configuring polarity, output, and sensing

Polarity and Lead Monitor

■

If bipolar lead impedance is outside this range, a unipolar lead is assumed to be present. The programmer warns that the test failed, and sensing polarity remains set to unipolar. This interlock feature may be overridden and lead sensing polarity forced to bipolar.

The Lead Monitor feature measures lead impedances during the life of the device. When programmed to do so, Lead Monitor causes the device to switch from bipolar pacing and sensing to unipolar pacing and sensing in the monitored bipolar lead if the measured impedance goes outside the limits of a preset range.

Caution: A notification that Lead Monitor has detected an out-of-range lead impedance is an indication that lead integrity should be thoroughly investigated.

How Lead Monitoring Works

The Lead Monitor feature monitors lead integrity in paced chambers (as defined by the pacing mode and ventricular pacing configuration) by measuring lead impedance every 3 hours. Impedance must fall within the programmed impedance range for a stable lead. The acceptable impedance range is from 200 ohms to a programmable value between 1000 and 4000 ohms.

Each paced chamber has its own set of Lead Monitor parameters. These parameters and the programmable options are listed below.

Parameter Options

Polarity Switch Monitor/Switch, Monitor Only, Off

Notify If < (lead impedance is less than 200 ohms)

Notify If > (lead impedance is greater than __ ohms)

(preset, not programmable)

1000, 2000, 3000, 4000 ohms

Polarity Switch – Sets Lead Monitor to operate according to one of these options:

Monitor/Switch - Monitor lead impedance and switch pacing and sensing polarity from Bipolar or LVtip/RVring to Unipolar when the device detects an out-of-range impedance.

InSync III Model 8042 Device Reference Guide

Chapter 4

Ventricular Pacing Configuration

Monitor Only - Monitor lead impedance but do not switch polarity when an out-of-range impedance is detected.

Off - Turns off Lead Monitor in the respective chamber.

Notify If < (less than) – Nonprogrammable minimum value for acceptable atrial and ventricular bipolar lead impedance. Fixed at 200 ohms.

Notify If > (greater than) – Programmable maximum limit for acceptable bipolar lead impedance for the monitored lead.

If Lead Monitor switches a lead from bipolar to unipolar polarity (Monitor/Switch option) or just detects an out-of range impedance value (Monitor Only option), the device issues a lead warning that appears on the programmer screen at the next interrogation.

Do not program the Lead Monitor Ventricular or Atrial Polarity Switch to Monitor/Switch for patients with an implantable defibrillator because the monitor automatically reprograms the selected lead(s) to unipolar polarity if an out-of-range lead is detected.

Ventricular Pacing Configuration

In addition to providing independently programmable output parameters (amplitude, pulse width, and polarity) for each ventricular chamber, the InSync III device has the following programmable parameters that allow you to further configure delivery of ventricular stimuli.

■

Ventricular Pacing

■

First Chamber Paced

■

V-V Pace De lay

■

Ventricular Sense Response

■

Maximum Response Rate

InSync III Model 8042 Device Reference Guide

Ventricular Pacing

Parameters:

PAV = 150 ms SAV = 120 ms Sense Polarity = RV Bipolar Ventricular Pacing = RV+LV First Chamber Paced = LV V-V Pace Delay = 20 ms

SAV V-V Pace Delay PAV

To provide cardiac resynchronization, the Ventricular Pacing parameter must be programmed to the RV+LV setting. Pacing stimuli are delivered to both ventricles. Initiation and delivery of a pacing stimulus to one chamber results in delivery of a pacing stimulus to the other chamber after a 4 ms delay, unless a longer V-V Pace Delay has been programmed.

Note: The RV and LV settings for this parameter allow for independent assessment of RV and LV lead performance.

First Chamber Paced

When biventricular (RV+LV) pacing is enabled, this parameter sets the first chamber to be paced as RV or LV. The delay interval between delivery of a pace to the first and second chamber is programmable (see “V-V Pace Delay” on page 87).

V-V Pace Delay

When biventricular (RV+LV) pacing is enabled, the V-V Pace Delay parameter sets the amount of time that elapses between delivery of a stimulus to the first ventricle paced and delivery of a stimulus to the other ventricle. The V-V Pace Delay, which has a minimum of 4 ms, can be programmed up to 80 ms.

Configuring polarity, output, and sensing

Ventricular Pacing Configuration

Figure 4-2. Example V-V Pace Delay

InSync III Model 8042 Device Reference Guide

Programmed V-V Pace Delay

Ventricular Sense Response Initiated at 8 ms

Maximum Response Rate Interval

V-V Pace Delay is 4 ms

Chapter 4

Ventricular Pacing Configuration

Ventricular Sense Response

Note: If Ventricular Safety Pacing or Ventricular Sense Response

is enabled, paces generated in response to a ventricular sense will be delivered at the minimum (4 ms) V-V delay.

Note: Also see “Pacing with a Shared Electrode and Short V-V Delay” on page 81.

Ventricular Sense Response is intended to provide cardiac resynchronization in the presence of ventricular sensing by allowing a ventricular sense to initiate a ventricular or biventricular pace. The programmable settings for Ventricular Sense Response are Off and Pace.

When Ventricular Sense Response is enabled in a dual chamber mode, a ventricular sense that occurs during the PAV interval initiates an immediate ventricular or biventricular pace. A ventricular sense that is preceded by a non-refractory atrial sense will initiate an immediate ventricular or biventricular pace if the pace does not exceed the programmed Maximum Response Rate.

InSync III Model 8042 Device Reference Guide

Figure 4-3. Ventricular Sense Response

When Ventricular Sense Response is enabled in a single chamber mode, a ventricular sense will initiate an immediate ventricular or biventricular pace if the pace does not exceed the programmed Maximum Response Rate.

The initiated paces are delivered according to the programmed Ventricular Pacing setting (RV, or RV+LV). If biventricular pacing (RV+LV) is enabled, the biventricular stimuli are delivered at the minimum (4 ms) V-V pace delay.

A count of the ventricular sense (VS) events that initiated a Ventricular Sense Response or a Ventricular Safety Pace is displayed with the Ventricular Rate Histogram (see page 128).

Maximum Response Rate

The programmable Maximum Response Rate applies when Ventricular Sense Response is enabled. This parameter determines the maximum rate at which ventricular or biventricular paces can be initiated in response to ventricular senses.

Maximum Response Rate can be programmed from 90 to 150 ppm. Maximum Response Rate applies to initiated responses in single chamber modes and to initiated responses during the SAV interval in dual chamber modes.

Configuring polarity, output, and sensing

Ventricular Pacing Configuration

With Ventricular Sense Response enabled, an initiated pace can occur only if the time elapsed since the last ventricular event represents a rate equal to or less than the programmed Maximum Response Rate.

InSync III Model 8042 Device Reference Guide

Chapter 4

Output and Sensitivity

Output (Amplitude and Pulse Width)

The InSync III device allows you to program separate amplitude and pulse width settings for each of the ventricular output channels and the atrial channel. Pacing output settings should be based on stimulation thresholds measured in each of the paced chambers. Stimulation energy should be high enough to ensure reliable capture, but not so high as to unnecessarily deplete the device battery.

Determining Stimulation Thresholds at Implant

At the time of device implantation, an external analyzer, such as a Medtronic Pacing System Analyzer or Lead Analysis Device, should be used to determine the stimulation threshold values for each pacing lead. Refer to the analyzer manual for detailed instructions.

Verifying Stimulation Thresholds at Follow-up

Medtronic 9790 series programmers provide both automatic and manual threshold tests for measuring the stimulation threshold of each lead at the time of patient follow-up. Stimulation threshold resolution is based on the programmable increments of amplitude and pulse width. A Strength-Duration test constructs a strength-duration graph that shows amplitude and pulse width safety margins.

Selecting Output Parameters

Generally, to provide an adequate safety margin, select a pacing voltage twice the chronic stimulation threshold voltage for a given pulse width. For most patients, pacing outputs are the major contributor to battery depletion.

To maximize battery longevity, select the lowest amplitude and pulse width settings that provide at least a 2:1 voltage safety margin. A greater safety margin may be advisable during the lead maturation process.

Note: Also see “Pacing with a Shared Electrode and Short V-V Delay” on page 81.

InSync III Model 8042 Device Reference Guide

Sensitivity

Configuring polarity, output, and sensing

Output and Sensitivity

Note: An amplitude of 7.5 V substantially reduces expected battery longevity. These amplitudes should be limited to short-term uses such as “Emergency” settings and electrophysiologic studies or long-term uses for specific indications such as exit block.

Note: High output pacing at 7.5 V may affect ECG or intracardiac electrogram (EGM) waveform quality and potentially cause crosstalk or self-inhibition.

For Additional Information

Refer to “Estimated Longevity Projections” on page 178 for further information on device longevity under various pacing scenarios. Refer to “Programmable Modes and Parameters” on page 192 for further information on amplitude and pulse width parameter settings. Refer to “Crosstalk and Self-Inhibition” on page 207 for further information on crosstalk or self-inhibition.

Sensitivity determines the minimum intracardiac signal that the device can detect when intrinsic atrial or ventricular events occur. Sensitivity settings should be based on the measured amplitude of the depolarization signal detected in each chamber at the time of device implantation and at follow-up. Intracardiac signal amplitudes can decrease during the lead maturation process.

Determining Sensing Signal Amplitudes at Implant

At implant, use a Medtronic Pacing System Analyzer or Lead Analysis Device to determine sensing threshold values for the device. Refer to the respective manual for detailed instructions.

Before connecting a bipolar lead, measure the sensing potentials in the unipolar and the bipolar configurations. Adequate intracardiac signal should be present in both configurations to ensure proper sensing in either.

InSync III Model 8042 Device Reference Guide

Chapter 4

Output and Sensitivity

Verifying Sensitivity Settings at Follow-up

The 9790 series programmer provides an automatic Sensing Test that allows the clinician to verify a patient’s sensitivity settings at follow-up. This test can determine the approximate amplitude of P or R waves detected by the atrial lead or the ventricular leads, respectively. The test displays the sensitivity setting just above and below the point at which P-wave or R-wave sensing occurs.

Selecting Sensitivity Settings

Atrial and ventricular sensitivity are independently programmable. In general, a 2:1 to 3:1 sensitivity safety margin (threshold sensitivity value divided by 2 or 3) is adequate for newly implanted or chronic leads. For example, an atrial sensitivity of 1.0 mV should be satisfactory for intrinsic atrial signals between 2.0 mV and 3.0 mV.

■

Always perform a sensing test for each applicable channel to determine the appropriate sensitivity setting.

■

Excessively sensitive (low) settings can cause some or all of the following problems:

– oversensing due to electromagnetic interference (EMI),

myopotentials, T waves, or crosstalk

– undersensing due to overloading of the sensing circuit

– noise reversion operation

■

Atrial Sensitivity with Bipolar sensing and Lead Monitor set to Off or Monitor Only allows 0.18 mV, 0.25 mV, and 0.35 mV atrial sensitivity settings. To prevent oversensing of muscle noise or electromagnetic interference, unipolar sensing is limited to values no less than 0.5 mV.

■

Ventricular Sensitivity at 1.0 mV or 1.4 mV with wide atrial pulse widths or high atrial amplitudes may result in ventricular safety pacing (if the Ventricular Safety Pacing feature is On) with some lead systems at high sensor-driven pacing rates. Reprogramming Ventricular Sensitivity to a less sensitive setting (higher numerical value) is one option under such circumstances. Other options include programming a longer ventricular blanking period.

InSync III Model 8042 Device Reference Guide

Configuring polarity, output, and sensing

Output and Sensitivity

Effects of Myopotentials During Unipolar Pacing

Myopotentials can affect device operation when sensing polarity is unipolar, especially with atrial sensitivity settings of 0.5 through

1.0 mV and ventricular sensitivity settings of 1.0 and 1.4 mV. Myopotentials sensed on the atrial channel outside the total atrial refractory period (SAV + PVARP) start sensed AV intervals in the DDDR, DDD, and VDD modes.

Continuous myopotentials cause reversion to asynchronous operation when sensed in the refractory period:

■

on the ventricular channel at intervals less than the ventricular refractory period in the DDDR, DDD, DDIR, DDI, DVIR, DVI, VDD, VVIR, VDIR, VVI, VDI, and VVT modes,

■

on the atrial channel at intervals less than the atrial refractory period in the AAIR, ADIR, AAI, ADI, and AAT modes.

In the VVIR and VDIR modes, the resulting asynchronous pacing occurs at the Lower Rate, otherwise such asynchronous pacing occurs at the sensor-indicated rate for rate response modes or the Lower Rate for non-rate response modes.

For Further Information

Refer to “Noise Reversion” on page 72 for a description of noise reversion operation. Refer to “Atrial Lead” on page 193 and “Right (RV) and Left (LV) Ventricular Leads” on page 193 for tables that provide sensitivity parameter settings. In the Pacing System Analyzer or Lead Analysis Device manual, refer to sensitivity threshold test procedures.

InSync III Model 8042 Device Reference Guide

Special therapy options

Non-Competitive Atrial Pacing 96

PMT Intervention 98

PVC Response 100

Ventricular Safety Pacing 103

Sleep Function 105

Pace atrium safely, no capture

Relative refractory period, atrial pace may induce atrial tachycardia

Pace atrium safely, capture

Chapter 5

Non-Competitive Atrial Pacing

Overview

Non-Competitive Atrial Pacing (NCAP) is intended to prevent triggering of atrial tachycardias by an atrial pacing stimulus that falls within the atrium’s relative refractory period. This feature may be programmed On or Off in the DDDR and DDD modes.

Figure 5-1. The Relative Refractory Period of the Atrium

How NCAP Affects Atrial Timing

InSync III Model 8042 Device Reference Guide

When NCAP is programmed On, a refractory sensed atrial event falling in the PVARP starts a 300-ms NCAP period, during which no atrial pacing may occur:

■

If a sensor-driven or lower rate pacing stimulus is scheduled to occur during the NCAP period, the VA interval is extended until the NCAP period expires.

If no pacing stimulus is scheduled to occur during the NCAP period, timing is unaffected; pacing occurs at the end of the VA interval unless inhibited.

An atrial refractory sensed event occurring during the NCAP period starts a new NCAP period.

How NCAP Affects Ventricular Timing

Sensor-Indicated

Interval

Sensor-Indicated

Interval

NCAP

300 ms

Sensor SensorNCAP

Parameters:

Sensor-Indicated Rate = 120 ppm (500 ms) PAV Interval = 150 ms PVARP Interval = 230 ms Post-Ventricular Atrial Blanking (PVAB) = 180 ms Ventricular Refractory Period = 230 ms

30 ms

When an atrial pacing stimulus is delayed by the NCAP operation, the device attempts to maintain a stable ventricular rate by shortening the PAV interval that follows. It will not, however, shorten the PAV interval to less than 30 ms. When a relatively high Lower Rate and long PVARP are programmed, NCAP operation may result in ventricular pacing slightly below the Lower Rate.

Figure 5-2. Non-Competitive Atrial Pacing Operation

Special therapy options

Non-Competitive Atrial Pacing

With biventricular pacing, event timing that involves a ventricular pace is always based on the first ventricular stimulus. The timing diagrams in this chapter depict only the first stimulus of a biventricular pacing output.

InSync III Model 8042 Device Reference Guide

Chapter 5

PMT Intervention

NCAP Availability

For Further Information

PMT Intervention

The Non-Competitive Atrial Pacing feature may be programmed On or Off only in the DDDR and DDD modes. Its availability is also dependent on the following:

■

When Mode Switch is programmed On, NCAP operations are temporarily disabled if the pacing mode switches to the non-atrial tracking mode. The NCAP feature is reenabled upon return to the atrial tracking mode.

■

Even when NCAP is programmed Off, the NCAP operation is invoked automatically for cycles on which PMT Intervention or PVC Response operations occur.

Refer to “Programming Mode Switch” on page 35, “PMT Intervention” on page 98, and “PVC Response” on page 100 for more information on these therapy features.

Overview

A Pacemaker-Mediated Tachycardia (PMT) may occur when retrograde P waves (due to a loss of AV synchrony) are sensed and tracked in an atrial tracking mode. PMT Intervention provides an automatic way for the device to detect and interrupt device-defined PMTs. This programmable On or Off feature is available in the DDDR, DDD, and VDD modes.

Caution: Even with the feature turned On, PMTs may still require clinical intervention such as device reprogramming, magnet application, drug therapy, or lead evaluation.

InSync III Model 8042 Device Reference Guide

How the Device Defines PMT

PVARP PVARP PVARP PVARP PVARP = 400 ms

Parameter:

PVARP = 280 ms

The device assumes that a PMT may be present when it detects a ninth ventricular pace following eight consecutive VA intervals that meet all of the following conditions:

■

Duration less than 400 ms

■

Start with a ventricular paced event

■

End with an atrial sensed event

PMT Therapy Intervention

When a device-defined PMT is detected, the device intervenes, forcing a 400-ms PVARP after the ninth paced ventricular event (see Figure 5-3). If a PMT is indeed in progress, the extended PVARP ensures that the next atrial sensed event within 400 ms will be refractory. By interrupting atrial tracking for one cycle, the PMT may be stopped.

Note: A sinus tachycardia could cause PMT therapy intervention, resulting in a single P wave falling in the PVARP and, therefore, not being tracked by the device.

Special therapy options

PMT Intervention

Figure 5-3. PMT Intervention

Automatic Therapy Suspension

After therapy intervention, PMT Intervention is automatically suspended for 90 seconds. This prevents unnecessary intervention in the presence of fast intrinsic atrial rates.

InSync III Model 8042 Device Reference Guide

100

Chapter 5

PVC Response

Interactions with Other Features

The PMT Intervention feature interacts with other device features in the following ways:

■

Patient Intervention for PMT

When Auto PVARP is active, the patient can often terminate a PMT simply by resting quietly, causing the sensor-indicated rate to drop and the PVARP to extend. When PVARP becomes longer than the retrograde time, the PMT may terminate.

For Further Information

Refer to “Non-Competitive Atrial Pacing” on page 96 and “Programming Mode Switch” on page 35 for more information on these therapies.

Non-Competitive Atrial Pacing (NCAP) is automatically enabled for one cycle after the ninth ventricular pace of a device-defined PMT episode. The NCAP feature may shorten the ensuing PAV to maintain a stable ventricular rate.

If Mode Switch is On, PMT Intervention is temporarily disabled if the device switches to the non-atrial tracking mode. It is reenabled upon return to the atrial tracking mode.

PVC Response

Overview

The Premature Ventricular Contraction (PVC) response feature is available in the DDDR, DDD, DDIR, DDI, and VDD modes. The feature, which is programmable On or Off, is intended for the following purposes:

DDDR, DDD, and VDD modes – PVC Response is intended to prevent tracking of retrograde P waves generated by PVCs. This response helps prevent initiation of pacemaker-mediated tachycardia.

InSync III Model 8042 Device Reference Guide

Medtronic 8042B Reference Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Contents

1 Pacing modes and the mode switch option 13

2 Programming rate and rate response parameters 39

3 AV intervals, refractory and blanking periods 55

4 Configuring polarity, output, and sensing 79

5 Special therapy options 95

6 Telemetry and transtelephonic follow-up features 107

7 Miscellaneous operations 117

8 Diagnostics 125

9 Troubleshooting the device system 139

A Device description 151

B Preset parameter settings 155

C Device programming recommendations 167

D Longevity projections, battery information 177

E Telemetry and diagnostic values 183

F Parameter values and restrictions 191

G Warnings, precautions, and EMI 199

H Clinical Studies 217

Index 219

I Glossary 227

Required Physician Training

How to Use This Guide

Information is Contained in Two Guides

About this Guide

About the Device Programming Guide

Understanding device operation

Pacing Modes

Biventricular Pacing

Atrial Pacing Modes

NBG Pacing Codes

Further Information

Mode Pertinency Tables

Indications and Usage

Contraindications

Clinical Outcomes

DDDR Mode

DDD Mode

DDIR Mode

DDI Mode

DVIR Mode

DVI Mode

VDD Mode

VVIR / VDIR Modes

VVI / VDI Modes

Other Available Modes

AAIR / ADIR Modes

AAI / ADI Modes

AAT / VVT Modes

DOOR / AOOR / VOOR Modes

DOO / AOO / VOO Modes

ODO / OAO / OVO Modes

Programming Mode Switch

Overview

Atrial Tachyarrhythmia Definition and Detection

Switching to Non-Atrial Tracking Mode

Switching Back to Atrial Tracking Mode

Mode Switching Interruption

Programming and Operating Restriction

Recording Mode Switch Episode Data

Programmable Rates

About A–A and V–V Timing

Lower Rate

Operating Lower Rate

Selecting a Lower Rate

Upper Tracking Rate

Upper Sensor Rate

Programming Considerations

Possible Atrial Competition at High Rates

Device Circuit Rate Limit

Rate Responsive Pacing

Overview

Sensor-Indicated Rate

Effect of Sensor-Indicated Rate on Other Intervals

Rate Response - Parameters and Operation

How Activity Threshold Influences Rate

Evaluating the Activity Threshold Setting