Medtronic 8040 Reference Guide

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INSYNC®

Device Model 8040

Reference Manual

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

InSync Model 8040

Device Reference Guide

Reference information about the InSync Model 8040 atrial synchronous biventricular pacing 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.

InSync, Marker Channel, Medtronic

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:

■

Indications for use

■

Device operation to ensure therapy delivery

■

Measuring and managing biventricular thresholds

■

Assembly and use of LV lead implant tools

■

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

This guide provides comprehensive information about the InSync Model 8040 and its programmable and follow-up functions.

Note: For specific programming procedures, refer to the InSync Model 8040 Device Programming Guide.

Organization of this guide divides information into two parts:

Part I - Understanding Device Operation – This part describes operation of the device system, which consists of the InSync device and the connected pacing leads. Included is information on pacing modes, rate response and special therapy options, diagnostic reporting features, and troubleshooting. Part II expands on the information provided in the device technical manual, which covers information needed primarily at the time of device implantation.

InSync Model 8040 Device Reference Guide

How to Use This Guide

Part II - Reference Information – This part includes quick-reference information organized by topic or feature. Various specifications, parameter values, and feature options are presented in tabular format.

InSync Model 8040 Device Reference Guide

Required Physician Training 5

How to Use This Guide 5

1 Pacing modes 13

Introduction 14

Mode Pertinency Tables 16

Indications and Usage 18

Contraindications 18

DDDR Mode 19

DDD Mode 20

DDIR Mode 21

DDI Mode 22

DVIR Mode 23

DVI Mode 24

VDD Mode 25

VVIR / VDIR Modes 26

VVI / VDI Modes 27

Other Available Modes 28

AAI / ADI Modes 29

AAT / VVT Modes 30

DOOR / AOOR / VOOR Modes 31

DOO / AOO / VOO Modes 32

ODO / OAO / OVO Modes 33

2 Rate response 35

Introduction to Rate Responsive Pacing 36

Activity Threshold 38

Activity Rate Response 40

Acceleration and Deceleration Times 42

Rate Response Optimization 44

3 Device timing 49

Rates 50

AV Intervals 58

InSync Model 8040 Device Reference Guide

Contents

Rate Adaptive AV 61

Blanking Periods 64

Refractory Periods 66

High Rate Atrial Tracking 74

4 Lead/cardiac tissue interface 77

Selecting Pacing Parameters 78

Selecting Sensing Parameters 83

Monitoring Lead Stability 86

Transtelephonic Capture Verification with TMT 89

5 Special therapy options 93

Mode Switch and Diagnostic 94

Non-Competitive Atrial Pacing 99

PMT Intervention 102

PVC Response 104

Ventricular Safety Pacing 107

Rate Drop Response 108

Sleep Function 113

Single Chamber Hysteresis 115

6 Telemetry data 117

Parameter Summary 118

Battery and Lead Information 119

Marker Channel Telemetry 121

Intracardiac Electrogram 122

Extended Telemetry 125

7 Miscellaneous operations 127

Magnet Mode Operation 128

Temporary Programming 130

Electrical Reset 131

Elective Replacement Indicator 133

Emergency Pacing 134

8 Diagnostics 135

Introduction to Diagnostics 136

Event Summary 138

InSync Model 8040 Device Reference Guide

Rate Histogram 140

AV Conduction Histogram 142

High Rate Episode 144

Rate Versus Time 148

9 Troubleshooting the device system 151

Troubleshooting Strategy 152

Troubleshooting Electrical Problems 153

Troubleshooting Hemodynamic Problems 155

Handling, Storage, and Resterilization 157

Device Longevity 158

Replacing the Device 159

Patient Information and Service 160

A Device description 165

Basic Description 166

Lead Compatibility 166

Radiopaque Code 167

Physical Dimensions 167

Connector Dimensions 168

Contents

B Preset parameter settings 169

Shipping Parameters 170

Nominal Settings 172

Electrical Reset Settings 174

Emergency Settings 176

C Device programming recommendations 177

Device Programming Recommendations 178

D Parameter values and restrictions 181

Programmable Modes and Parameters 182

Programming Requirements and Restrictions 186

Nonprogrammable Parameters 189

Temporary Modes and Parameters 189

Timing Reference 190

E Telemetry and diagnostic values 195

Magnet Mode Operation 196

InSync Model 8040 Device Reference Guide

Contents

Telemetry Functions 197

Diagnostic Options 198

Event Summaries 200

F Longevity projections 201

Longevity Projections (Normal Operating Life) 202

Prolonged Service Period 203

Elective Replacement Indicator (ERI) 204

Battery Specifications 204

G Warnings, precautions, and EMI 205

Special Notice 206

Warnings 207

Precautions 212

Potential Complications 217

Environmental and Medical Therapy Hazards 218

Home and Job Environment Interference 221

H Clinical Studies 225

Clinical Studies 226

I Glossary 227

Index 233

InSync Model 8040 Device Reference Guide

Understanding device operation

Part I

Introduction 14

Mode Pertinency Tables 16

Indications and Usage 18

Contraindications 18

DDDR Mode 19

DDD Mode 20

DDIR Mode 21

DDI Mode 22

DVIR Mode 23

DVI Mode 24

VDD Mode 25

VVIR / VDIR Modes 26

Pacing modes

VVI / VDI Modes 27

Other Available Modes 28

AAI / ADI Modes 29

AAT / VVT Modes 30

DOOR / AOOR / VOOR Modes 31

DOO / AOO / VOO Modes 32

ODO / OAO / OVO Modes 33

Chapter 1

Introduction

Pacing Mode Selection

Delivery of Cardiac resynchronization therapy requires that patients receive biventricular pacing for each cardiac cycle. Special consideration is required in programming device parameters for the InSync system to provide continuous biventricular pacing.

This chapter provides an introduction to pacing modes as an aid to mode selection. The chapter is organized as follows:

■

Mode Pertinency Tables – These tables show the features and parameters that apply to each commonly used pacing mode.

■

Mode Descriptions – Brief descriptions of how the available modes operate.

Note: The biventricular pacing capability of the InSync device does not affect the event timing operation of the pacing modes described in this chapter. The two ventricular leads are connected to the device in a parallel configuration that provides simultaneous pacing at both ventricular stimulation sites.

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

InSync Model 8040 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

Introduction

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

Further Information

Figure 1-1. NBG Pacing Codes

For biventricular pacing, a subset of these modes applies, e.g., VDD, DDD.

The mode descriptions in this chapter provide only a basic overview of each mode. For further details on rate response, timing, and therapy capabilities refer to “Rate response” on page 35, “Device timing” on page 49, and “Special therapy options” on page 93.

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 Model 8040 Device Reference Guide

Chapter 1

Mode Pertinency Tables

✓✓✓ ✓✓

✓✓✓✓ ✓

Pacing Operation Parameters

✓ ✓ ✓ ✓✓✓ ✓ ✓ ✓✓✓✓ ✓ ✓✓✓ ✓

Lower Rate

✓✓ ✓

Upper Tracking

Rate

Table 1-1 and Table 1-2 show which pacing parameters and features apply to each pacing mode

as indicated by black check marks. Asynchronous modes are not shown in these tables.

Mode Pertinency Tables

InSync Model 8040 Device Reference Guide

Table 1-1. Pacing Parameters Available For Each Mode

Pacing Parameter DDDR DDD DDIR DDI DVIR DVI VDD VVIR VDIR VVI VDI VVT AAIR ADIR AAI ADI AAT

✓✓✓ ✓✓ ✓✓

✓ ✓ ✓ ✓✓✓

✓✓ ✓

✓✓✓✓✓

Upper Activity Rate

Paced AV Interval

Sensed AV Interval

Rate Adaptive AV

✓ ✓✓✓ ✓

PVARP

✓ ✓✓✓ ✓ ✓ ✓

PVAB

Atrial Refractory

✓ ✓ ✓ ✓✓✓ ✓ ✓ ✓✓✓✓

✓ ✓ ✓ ✓✓✓ ✓ ✓

Period

Atrial Blanking

Ventricular

Refractory Period

Ventricular Blanking

(after AP)

See “Device timing” on page 49 for operational descriptions of these timing parameters.bSensor-varied PVARP available in the DDDR, DDD, DDIR, and VDD modes.

Pacing modes

Mode Pertinency Tables

✓✓ ✓ ✓ ✓ ✓

Special Therapy Options

Rate Response Therapy Options

✓✓

✓✓ ✓

✓

Feature DDDR DDD DDIR DDI DVIR DVI VDD VVIR VDIR VVI VDI VVT AAIR ADIR AAI ADI AAT

Table 1- 2. Features Available For Each Mode

Managing Atrial

Rhythm

Mode Switch

Non-Competitive Atrial

Pacing

Managing Ventricular Rhythm

✓✓ ✓

✓✓✓✓ ✓

PMT Intervention

PVC Response

✓ ✓ ✓✓✓✓

Ventricular Safety Pacing

Special Pacing Operations

Rate Drop Response

✓ ✓ ✓✓✓✓✓ ✓ ✓✓✓✓ ✓ ✓✓ ✓✓

✓✓✓ ✓✓ ✓✓

Single Chamber

Hysteresis

Sleep Function

Activity Rate Response

Activity Threshold

Activity Acceleration

Activity Deceleration

Rate Response

Optimization

InSync Model 8040 Device Reference Guide

See “Special therapy options” on page 93 for operational descriptions of special therapy options.bSee “Rate response” on page 35 for operational descriptions of rate response features.

Chapter 1

Indications and Usage

Contraindications

The InSync Model 8040 is indicated for the reduction of the symptoms of moderate to severe heart failure (NYHA Functional Class III or IV) in those 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 QRS duration ≥ 130 ms.

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 or cardioverter-defibrillator (ICD) because it may cause unwanted delivery or inhibition of defibrillator or ICD therapy.

InSync Model 8040 Device Reference Guide

DDDR Mode

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

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 Activity 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.

Figure 1-2. Example of DDDR Mode Operation

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

InSync Model 8040 Device Reference Guide

Lower Rate Interval

Parameters:

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

SAV Interval = 170 ms

DDD Mode

Chapter 1

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).

■

Ventricular paced events 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.

Figure 1-3. Example of DDD Mode Operation

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

InSync Model 8040 Device Reference Guide

DDIR Mode

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

Pacing modes

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.

■

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.

Figure 1-4. Example of DDIR Mode Operation

InSync Model 8040 Device Reference Guide

Lower Rate Interval

Parameters:

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

Lower Rate Interval

Lower Rate

VA I n t erv a l

Chapter 1

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.

Figure 1-5. Example of DDI Mode Operation

InSync Model 8040 Device Reference Guide

DVIR Mode

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

Pacing modes

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.

Figure 1-6. Example of DVIR Mode Operation

InSync Model 8040 Device Reference Guide

Lower Rate Interval

Parameters:

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

Lower Rate

VA Interval

Chapter 1

DVI Mode

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.

Figure 1-7. Example of DVI Mode Operation

InSync Model 8040 Device Reference Guide

VDD Mode

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

Pacing modes

VDD Mode

The VDD mode provides atrial synchronous pacing (or VVI pacing at the Lower Rate). The ventricle is paced synchronously up to the programmed Upper Tracking Rate.

Sensing occurs in both the

atrium and ventricle, but pacing occurs only in the ventricle.

■

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 both AV synchrony and cardiac resynchronization therapy.

Figure 1-8. Example of VDD Operation

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

InSync Model 8040 Device Reference Guide

Parameters:

Lower Rate = 60 ppm (1000 ms) Upper Activity 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 Activity

Rate Interval

Chapter 1

VVIR / VDIR 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 ventricle is 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 Activity 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.

Figure 1-9. Example of VVIR Mode Operation

InSync Model 8040 Device Reference Guide

VVI / VDI Modes

Pacing Rate Interval

Parameters:

Pacing Rate = 60 ppm (1000 ms)

Ventricular Refractory Period = 300 ms

Pacing Rate Interval

The VVI mode provides single chamber inhibited pacing at the programmed Lower 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 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

VVI / VDI Modes

Figure 1-10. Example of VVI Mode Operation

InSync Model 8040 Device Reference Guide

Operation:

Sensor-indicated Rate = 75 ppm (800 ms)

Upper Activity Rate = 100 ppm (600 ms)

Sensor-indicated Interval Sensor-indicated Interval

Chapter 1

Other Available Modes

AAIR / ADIR Modes

Warning: Atrial only pacing modes do not provide cardiac

resynchronization.

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 Activity 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.

Figure 1-11. Example of AAIR Mode Operation

InSync Model 8040 Device Reference Guide

AAI / ADI Modes

Pacing Rate Interval

Parameters:

Pacing Rate = 75ppm (800 ms)

Pacing Rate Interval

The AAI mode provides single chamber inhibited atrial pacing. Sensing and pacing occur only in the atrium. Pacing occurs at the programmed Lower 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.

Pacing modes

AAI / ADI Modes

Figure 1-12. Example of AAI Mode Operation

InSync Model 8040 Device Reference Guide

Pacing Rate Interval

Parameters:

Pacing Rate = 60 ppm (1000 ms)

Ventricular Refractory Period = 300 ms

Pacing Rate Interval

Chapter 1

AAT / VVT Modes

Pacing occurs at the programmed 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.

Note: Permanently 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.

Figure 1-13. Example of VVT Mode Operation

InSync Model 8040 Device Reference Guide

DOOR / AOOR / VOOR Modes

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

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

DOOR / AOOR / VOOR Modes

Figure 1-14. Example of DOOR Mode Operation

InSync Model 8040 Device Reference Guide

Lower Rate Interval

Parameters:

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

Lower Rate Interval

Chapter 1

DOO / AOO / VOO Modes

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

■

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.

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.

Figure 1-15. Example of DOO Mode Operation

InSync Model 8040 Device Reference Guide

ODO / OAO / OVO Modes

Warning: The ODO, OVO, and OAO modes should never be

permanently programmed for pacemaker-dependent patients.

■

For such patients, the programmer’s Inhibit function may be used for brief interruption of output.

■

Use of a magnet with these modes causes OOO operation, i.e., no sensing or pacing. Do not leave the patient in any of these modes without constant monitoring and supervision.

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.

Pacing modes

ODO / OAO / OVO Modes

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

InSync Model 8040 Device Reference Guide

Introduction to Rate Responsive Pacing 36

Activity Threshold 38

Activity Rate Response 40

Acceleration and Deceleration Times 42

Rate Response Optimization 44

Rate response

Chapter 2

Introduction to Rate Responsive Pacing

Overview

Rate responsive modes are available for those heart failure patients who may develop a need for rate responsive pacing. Rate responsive pacing was not studied in this patient population. These modes should not be programmed unless the patient needs this type of support.

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

■

Dual chamber modes: DDDR, DDIR, DVIR, DOOR

■

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

All of the rate response features discussed in this section apply to all of these modes, except for Rate Response Optimization. Refer to “Parameter values and restrictions” on page 181 for specific capabilities.

Sensor-Indicated Rate

In rate responsive modes, pacing occurs at the sensor-indicated rate unless inhibited by sensed events. The pacing rate may vary as the patient’s activity level changes. The sensor-indicated rate is determined from the activity sensor signal and the following programmable parameters:

■

Lower Rate

■

Upper Activity Rate

■

Activity Threshold

■

Activity Rate Response

■

Acceleration

■

Deceleration

The Lower Rate and Upper Activity Rate respectively control the minimum and maximum sensor-indicated pacing rates. The other parameters are described in the sections that follow.

InSync Model 8040 Device Reference Guide

Typical Rate Response Settings

The nominal rate response parameters are adequate for many patients (Activity Threshold = Medium, Activity Rate Response = 7, Acceleration = 0.5 minutes, and Deceleration = 5 minutes). For heart failure patients, rate response should only be programmed when necessary.

■

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.

■

When the patient is walking at a moderate pace, the pacing rate will typically increase to about 90 ppm, and up to 120 ppm during more brisk exercise. If the patient has minimal rate response during exercise, Activity Threshold may need to be programmed to a lower setting.

■

A simple programmer-directed exercise test may be used to tailor rate response settings to a patient’s needs (refer to InSync Model 8040 Device Programming Guide).

■

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

Rate response

Introduction to Rate Responsive Pacing

InSync Model 8040 Device Reference Guide

Time

Activity Threshold = Medium

Activity

Sensor

Output

High

MHigh

Med

MLow

Low

MLow

Med

MHigh

High

Settings

Chapter 2

Activity Threshold

Overview

The programmable Activity Threshold determines the minimum intensity of detected physical activity to which the device responds.

How Activity Threshold Influences Rate

A piezoelectric crystal, bonded to the inside of the titanium device shield, is deflected by activity-induced pressure waves within the body. The sensor converts these pressure waves into electrical signals. The programmed Activity Threshold screens out activity signals below the selected setting. Detected sensor signals will vary from patient to patient due to body structure, placement of device, and so forth. Only sensor signals whose amplitude exceeds the programmed Activity Threshold are used in computing the sensor-indicated pacing rate. The lower the Activity Threshold, the smaller the signal required to influence the pacing rate, as shown in Figure 2-1.

Figure 2-1. Activity Sensor Signal with Threshold Set to Medium

InSync Model 8040 Device Reference Guide

Evaluating the Activity Threshold Setting

Marker Channel telemetry may be used to record or display the activity sensor signal for evaluation. Few (or no) sensor detect markers should appear when the patient is sitting quietly.

Typical Rate Performance

The Medium setting for Activity Threshold usually provides satisfactory rate response while minimizing response to vibration sources when the patient is inactive. Walking increases pacing rate; sitting results in pacing at or near the Lower Rate. Use the table below as a guide for selecting an appropriate setting.

Note: External pressure (such as lying prone) coupled with a Low Activity Threshold setting may cause the pacing rate to increase.

Tab le 2-1. Activity Threshold Guidelines

Programmable Settings

Typical Rate Performance

Rate response

Activity Threshold

Low Responds to most body activity, including

Medium/Low Limited response to minimal exertion;

Medium Responds to moderate and vigorous body

Medium/High Limited response to moderate body

High Responds to only vigorous body movements

minimal exertion.

responds to moderate or greater exertion.

movements and exertion.

and exertion.

InSync Model 8040 Device Reference Guide

Chapter 2

Activity Rate Response

Overview

Basic Operation

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

■

Ten Activity Rate Response slopes 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 Activity Rate Response setting.

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

■

All Activity Rate Response slopes are linear and extend from the Lower Rate to the Upper Activity Rate.

■

The Upper Activity Rate can be attained with any Activity Rate Response slope.

■

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

Determining the Steady-State Pacing Rate

For any Activity Rate Response slope, the steady-state rate corresponding to a given level of activity depends on Lower Rate (LR) and Upper Activity Rate (UAR).

Figure 2-2 shows the Activity Rate Response slopes for two sets of rate limits, first for an elderly patient and second for a younger patient. For a given Activity Rate Response slope (for example, slope 7), both patients achieve their Upper Activity Rates for the same level of sustained sensor-detected activity, but the rates are quite different. Use the programmed rate limits and Activity Rate Response to match the rate prescription to the patient’s needs.

InSync Model 8040 Device Reference Guide

elderly patient

younger patient

Pacing Rate (ppm)

Increasing activity

Rate response

Activity Rate Response

Figure 2-2. Activity Rate Response Settings

InSync Model 8040 Device Reference Guide

Time (Minutes)

Rate Range

Lower

Rate

Upper

Activity

Rate

Activity Acceleration

Programmable Settings

0.25 Minutes

0.5 Minutes

1.0 Minutes

Chapter 2

Acceleration and Deceleration Times

Overview

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

Rate responsive pacing was not studied in this patient population. Consider this when deciding how to program acceleration time.

Acceleration Operation

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 2-3 shows a graphic representation of the Acceleration curves at the onset of strenuous exercise.

InSync Model 8040 Device Reference Guide

Figure 2-3. Activity Acceleration Curves

Deceleration Operation

Time (Minutes)

Rate Range

Lower

Rate

Upper

Activity

Rate

Activity Deceleration

Programmable Settings

2.5 Minutes

5 Minutes

10 Minutes

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 2-4 shows a graphic representation of the Deceleration curves at an abrupt cessation of strenuous exercise.

Rate response

Acceleration and Deceleration Times

Figure 2-4. Activity Deceleration Curves

Exercise Deceleration Operation

Exercise Deceleration extends the rate slowing period following an exercise episode, providing up to 20 minutes of rate deceleration. When it is programmed On, 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 rate (longer deceleration time) 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 2-5 shows the composite deceleration curve that applies after the abrupt cessation of sustained exercise.

InSync Model 8040 Device Reference Guide

Time (Minutes)

Rate Range

Lower

Rate

Upper

Activity

Rate

5 Minute Deceleration Curve

Begins Exercise Deceleration

Ends Exercise

Deceleration

5 Minute

Deceleration

Curve

Chapter 2

Rate Response Optimization

Figure 2-5. Exercise Deceleration

Rate Response Optimization

Overview

Rate Response Optimization is a programmable On/Off feature that adapts rate responsive pacing to the patient’s changing pacing needs by automatically reprogramming the Activity Rate Response setting.

InSync Model 8040 Device Reference Guide

Caution: Rate Response Optimization may not be appropriate for patients where it is necessary to limit the rate response to exercise. Rate response pacing has not been studied in this patient population.

■

The clinician programs the Patient Lifestyle parameter based on the patient’s usual level of activity or work: Active, Moderately Active, or Less Active. The Moderately Active setting should work for most patients.

The adjustment of Activity Rate Response is based on a running average of the patient’s activity.

■

For dramatic changes in patient activity, Activity Rate Response adjustment may occur in as few as three days. (An example might be an acute illness that limits the patient’s activity.)

■

For more gradual changes in patient activity, the adjustment may require two weeks or more. (An example might be the period immediately following implant when cardiovascular training effects sometimes occur.)

When reprogramming occurs, the Event Summary reports the number of adjustments the next time the device is interrogated.

Rate Response Optimization Operation

Activity Rate Response slope adjustment is based on the average number of daily exercise episodes. The device cumulates the number of exercise episodes into a running average. Once each day, the running average is compared with minimum and maximum exercise episode values appropriate for the programmed Patient Lifestyle.

■

If the average is above the maximum, the device adjusts the programmed Activity Rate Response slope to the next lower (less aggressive) setting.

■

If the average is below the minimum, the device adjusts the programmed Activity Rate Response slope to the next higher (more aggressive) setting.

Rate response

Rate Response Optimization

Programming Considerations

When programming Rate Response Optimization On, the clinician should consider how the programmed Patient Lifestyle and Activity Threshold settings may affect the actual rate response observed for a given patient. The clinician should also consider how adjustment of the Activity Rate Response slope affects achieving the programmed Upper Activity Rate.

■

The Patient Lifestyle parameter determines how easily the number of daily exercise episodes are achieved for the patient's activity level. Programming the Less Active setting for a normally active patient may result in no change or a change to a lower (less aggressive) setting of the Activity Rate Response parameter. Conversely, programming the Active setting for a sedentary or minimally active patient may result in

InSync Model 8040 Device Reference Guide

Chapter 2

Rate Response Optimization

a change to a higher (more aggressive) setting. Select the appropriate setting with consideration of the device patient’s activity level against the population as a whole. For example, a 65-year-old heart failure patient may be considered to be “less active” in relation to the general population.

■

The Activity Threshold parameter determines the minimum intensity of detected physical activity to which the device responds by pacing. Sensor driven pacing contributes to the number of daily exercise episodes. Programming a less sensitive setting (e.g., Medium/High) for a normally active patient may contribute to fewer daily exercise episodes and result in a change to a higher (more aggressive) setting of the Activity Rate Response parameter.

■

The programmed Upper Activity Rate can be achieved with any of the programmed Activity Rate Response slopes. If the device reprograms the Activity Rate Response parameter, the level of exertion to achieve the Upper Activity Rate will change. Lower (less aggressive) settings will require more exertion, whereas higher (more aggressive) settings will require less exertion.

Note: Extended periods of patient inactivity (e.g., bed rest due to illness) may cause the device to adjust the Activity Rate Response parameter to a higher (more aggressive) setting. This may be important for heart failure patients.

InSync Model 8040 Device Reference Guide

Reporting Rate Response Parameter Changes

When Rate Response Optimization is active, the Activity Rate Response parameter may be changed from the setting last programmed. When the device is interrogated, the Event Summary will report the total number of adjustments.

Recording Rate Response Optimization Events

Rate response adjustment may be recorded using the Rate Response Optimization diagnostic. When this diagnostic is selected, it records the time and the new parameter setting whenever the Activity Rate Response is reprogrammed. Two recording methods are available:

■

The Frozen method documents up to 120 changes.

■

The Rolling method documents the most recent 120 changes, overwriting older data, if necessary.

Because 120 changes between programming sessions are highly unlikely, the two recording methods will generally perform identically.

Figure 2-6 shows how the Rate Response Optimization report is presented on the programmer. The report can be printed out or displayed on the programmer.

Rate response

Rate Response Optimization

Figure 2-6. Example of Rate Response Optimization Diagnostic

InSync Model 8040 Device Reference Guide

Chapter 2

Rate Response Optimization

Possible Loss of Diagnostic Data

Certain programmer functions erase stored diagnostic data. Review or print optimization data before performing any of the following functions:

■

Note: The Rate Response Optimization diagnostic is disabled and all episode data erased if the Lead Monitor automatically enables the Lead Trend diagnostic. See “Monitoring Lead Stability” on page 86 for more information on this feature. Diagnostic data collection is suspended if the Elective Replacement Indicator is set, but data already collected are retained.

programming another diagnostic,

using the programmer “Clear Data” command, or

initiating an activity threshold test or exercise test.

InSync Model 8040 Device Reference Guide

Rates 50

AV Intervals 58

Rate Adaptive AV 61

Blanking Periods 64

Refractory Periods 66

High Rate Atrial Tracking 74

Device timing

Chapter 3

Rates

Overview

The following programmable rates control timing in the device:

■

Normal operating rates:

– Lower Rate

– Upper Tracking Rate

– Upper Activity Rate

■

Other operating rates:

– Sleep Rate (for Sleep Function)

– Hysteresis Rate (for single chamber demand modes)

– Intervention Rate (for Rate Drop Response)

Additionally, rates calculated by the device are used for some operations. These are:

■

sensor-indicated rate

■

mean atrial rate

The other operating rates are described in “Special therapy options” on page 93 along with the functions that use them. The normal rates are described in this chapter.

InSync Model 8040 Device Reference Guide

A-A and V-V Timing

Device timing

Rates

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 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 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).

InSync Model 8040 Device Reference Guide

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

Chapter 3

Rates

Lower Rate

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

Figure 3-1. Example of Lower Rate Operation

InSync Model 8040 Device Reference Guide

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:

■

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, and ADI modes.

Device timing

Rates

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

Sleep rate (for Sleep function)

Intervention rate (for Rate Drop Response)

Hysteresis rate (for single chamber modes)

Threshold margin test rate of 100 ppm

Magnet mode rate of 85 ppm

Elective replacement indicator rate of 65 ppm

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.

InSync Model 8040 Device Reference Guide

Activity

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-Indicated Interval

Chapter 3

Rates

Sensor-Indicated Rate

The sensor-indicated rate is the basic pacing rate in all rate responsive modes (DDDR, DDIR, DVIR, DOOR, VVIR, VDIR, VOOR, AAIR, ADIR, and AOOR). It is determined by the device based on the sensor-detected level of patient activity and the programmed rate response parameters. The sensor-indicated rate will never be greater than the Upper Activity Rate or less than the Lower Rate.

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

In rate responsive modes, the sensor-indicated rate tracks the activity signal detected by the piezoelectric crystal sensor’s frequency and amplitude.

■

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 Model 8040 Device Reference Guide

Sensor Indicated Rate Effect on Other Intervals

Upper Tracking Rate

Parameters:

Sensor-indicated Rate =

75 ppm (800 ms)

Upper Tracking Rate =

100 ppm (600 ms)

SAV Interval = 200 ms

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

■

Rate adaptive paced AV (PAV) interval

■

Sensor-varied PVARP (even in nonrate responsive DDD and VDD modes)

Upper Tracking Rate

For heart failure patients, the upper tracking rate should be set to a value above the patient’s expected maximum intrinsic rate to insure that cardiac resynchronization therapy is provided throughout the range of patient activity. “Device Programming Recommendations” on page 178.

The programmable Upper Tracking Rate is the maximum rate at which the ventricle 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 result in pacemaker Wenckebach by gradual extension of the SAV (causing for example 6:5, 4:3, 3:2, or 2:1 block). The Upper Tracking Rate usually should be programmed to a value less than the 2:1 block rate. Refer to “High Rate Atrial Tracking” later in this chapter for details.

Device timing

Rates

Figure 3-3. Example of Upper Tracking Rate (Wenckebach) Operation

InSync Model 8040 Device Reference Guide

Chapter 3

Rates

Note: In situations where the patient is sensitive to variations in the AV interval, special consideration should be given to selecting a value for Upper Tracking Rate that will provide protection against inappropriately high ventricular rates while reducing the variations in the SAV that result from Wenckebach operation (see “Pacemaker Wenckebach” on page 75).

Upper Activity Rate

In rate responsive modes, the programmable Upper Activity Rate provides the upper limit for the sensor-indicated rate during physical activity, particularly during vigorous exercise. In the DDDR mode, the Upper Activity Rate may be higher than, lower than, or the same as the Upper Tracking Rate.

Programming Considerations and Restrictions

Programming a combination of high Upper Activity 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 99 for more information.

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

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

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. The rate limit is automatically disabled during temporary pacing in the AAI, ADI, AAT, AOO, VVI, VDI, VVT, and VOO modes to allow high rate pacing for diagnostic or therapeutic purposes.

InSync Model 8040 Device Reference Guide

Limiting Response to Environmental Vibration

In a rate responsive mode, the device may respond to strong environmental vibrations (such as from heavy machinery, extreme acoustic sources, prolonged device palpation, exercise equipment, and so forth) by pacing at elevated rates. (Such rates are always limited by the programmed Upper Activity Rate.) To eliminate this response, move the patient away from the vibration source. If this is not possible, reprogram the Upper Activity Rate setting to a value that is appropriate to the patient’s condition or adjust the Activity Threshold to a less sensitive setting.

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 in 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 Activity 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.

Device timing

Rates

Mean Atrial Rate

Note: Use of the Rate Adaptive AV feature, sensor-varied PVARP,

and Non-Competitive Atrial Pacing (DDDR mode only) can reduce the likelihood of the type of asynchronous pacing described above.

The mean atrial rate (MAR) is a running average of the atrial rate for use by the Rate Adaptive AV and automatic PVARP features. The average uses all A-A intervals (except those starting with an atrial sense or atrial refractory sense and ending with an atrial pace). 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 3-4 shows how the MAR tracks an increasing intrinsic atrial rate.

InSync Model 8040 Device Reference Guide

Atrial Rate Increasing by 2 bpm/beat

Time (Seconds)

Rate (bpm)

MAR

Intrinsic Rate

Chapter 3

AV Intervals

Figure 3-4. Mean Atrial Rate

Overview

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

■

Paced AV Interval (PAV) – PAV follows an atrial pace in the DDDR, DDD, DDIR, DDI, DVIR, DVI, DOOR, and DOO modes. The PAV interval duration may differ from the

InSync Model 8040 Device Reference Guide

programmed value due to:

– Rate Adaptive AV operation,

– Ventricular Safety Pacing, or

– Non-Competitive Atrial Pacing therapy.

Device timing

PAV

Interval

PAV

Interval

PAV PAV

AV Intervals

Figure 3-5. Example of PAV Interval Operation

■

Sensed AV Interval (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:

– Rate Adaptive AV operation or

– Wenckebach operation, where the SAV is extended to

avoid violation of the Upper Tracking Rate or the total atrial refractory period while tracking a fast intrinsic atrial rate.

InSync Model 8040 Device Reference Guide

SAV

Interval

SAV

Interval

SAV SAV

Chapter 3

AV Intervals

Selecting PAV and SAV

Figure 3-6. Example of SAV Interval Operation

When programming 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 certain patients, short AV intervals may be used as a prophylaxis for AV nodal or accessory pathway reentrant tachycardias in dual chamber modes.

■

For consistent ventricular pacing, the programmed setting for PAV and SAV must be less than the patient’s intrinsic PR interval.

InSync Model 8040 Device Reference Guide

■

Rate Adaptive AV

Overview

For heart failure patients, rate adaptive AV can be used to ensure pre-stimulation of the patient’s ventricles at higher rates.

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:

■

Device timing

Rate Adaptive AV

Long PAV intervals (≥ 250 ms) should not be used, as they may not allow for optimal biventricular pacing.

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)” and “High Rate Atrial Tracking” later in this chapter 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.

Programming for Rate Adaptive AV

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

Start Rate – RAAV operation of shortening AV 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.

InSync Model 8040 Device Reference Guide

Rate (ppm)

AV Interval (ms)

Parameters:

Programmed SAV = 170 ms Start Rate = 80 ppm Minimum PAV = 100 ms

Programmed PAV = 200 ms Stop Rate = 150 ppm Minimum SAV = 70 ms

Start Rate Stop Rate

Programmed PAV

Programmed SAV

Minimum SAV

Minimum PAV

Chapter 3

Rate Adaptive AV

Minimum AV Interval – A minimum value is selected for either the SAV or PAV, 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.

Figure 3-7 shows how the SAV and PAV intervals are linearly shortened as the rate increases from below the Start Rate to above the Stop Rate.

Figure 3-7. Rate Adaptive AV Operation (DDDR Mode)

InSync Model 8040 Device Reference Guide

RAAV Operations

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).

– Atrial sensed or atrial refractory sensed events may affect

the SAV if the next atrial event is not paced since these A-A events are not used in the mean atrial rate.

■

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.

Programming Considerations and Restrictions

Device timing

Rate Adaptive AV

RAAV subordinate parameters – The Start Rate must be less than the Stop Rate. The Min Sensed AV and Min Paced AV intervals must be less than the programmed SAV and PAV, respectively. The Min Paced AV interval is set to a pending value for DDDR or DDD mode switching.

InSync Model 8040 Device Reference Guide

Note: Black bars indicate blanking periods.

1 1.Nonprogrammable Atrial

Blanking

2 2.Programmable

Post-Ventricular Atrial Blanking

3 3.Programmable Ventricular

Blanking

4 4.Nonprogrammable Ventricular

Blanking

Chapter 3

Blanking Periods

Using RAAV with Mode Switch

Blanking Periods

RAAV operation is enabled when Mode Switch is selected, RAAV parameter choices are affected as follows:

■

Start Rate must be less than or equal to 70 ppm.

■

Stop Rate is forced to 150 ppm by the programmer.

■

Minimum SAV is forced to 30 ms.

■

Minimum PAV is forced anywhere from 30 to 100 ms for the DDDR and DDD modes.

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 3-8. Example of Dual Chamber Blanking Operation

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 Model 8040 Device Reference Guide

Post-Ventricular Atrial Blanking

The programmable Post-Ventricular Atrial Blanking (PVAB) period, used in the DDDR, DDD, DDIR, DDI, and VDD 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 since PVARP does not apply to these modes.

Note: PVAB is programmed 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 pacing.

■

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.

Device timing

Blanking Periods

InSync Model 8040 Device Reference Guide

Chapter 3

Refractory 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.

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, 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 and Marker Channel Diagrams.

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 Model 8040 Device Reference Guide

Device timing

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 and Marker Channel Diagrams, but they do not affect stimulus timing. That is:

■

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 3-9. Example of PVARP Operation

The duration of the PVARP may be selected as follows:

■

Sensor-Varied PVARP

When sensor-varied PVARP is programmed on, the device determines a value for the PVARP based on the sensor-indicated rate. The intended purpose of the sensor-varied PVARP depends upon the mode:

■

The PVARP should be programmed to a value greater than the patient’s retrograde (VA) 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 vary based on the sensor-indicated rate.

In the DDDR, DDD, and VDD modes, sensor-varied PVARP is intended to do the following:

InSync Model 8040 Device Reference Guide

Upper

Activity

Rate

Lower Rate

PAV PVARP

PAV

PVARP

Chapter 3

Refractory Periods

– Enhance protection against PMT at lower rates by

providing longer PVARPs at low sensor-indicated rates.

– Allow tracking of higher atrial rates (that is, provide a higher

2:1 block rate) by shortening the PVARP at high sensor-indicated rates.

■

In the DDIR mode, the sensor-varied PVARP is intended to promote AV synchrony by preventing inhibition of atrial pacing by an atrial sense early in the VA interval. It also reduces the likelihood of competitive atrial pacing at high sensor-indicated rates.

Note: When Rate Drop Response is on in the DDD mode, sensor-varied PVARP is not available.

Figure 3-10. Sensor-Varied PVARP Operation (DDDR Mode)

InSync Model 8040 Device Reference Guide

Determining Sensor-Varied PVARP

The device determines the duration of the sensor-varied PVARP as follows:

■

In the DDDR, DDD, and VDD modes, the sensor-varied PVARP is limited to 400 ms at low rates and the programmed PVAB at high rates (as shown in Figure 3-10).

■

In the DDIR mode, the sensor-varied PVARP is approximately 400 ms at low rates and the programmed PVAB at high rates.

■

In the DDDR, DDD, DDIR, and VDD modes, the sensor-varied PVARP is automatically adjusted to maintain a 300-ms sensing window (as shown in Figure 3-10).

Spontaneous PVARP Extension

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

■

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.

Device timing

Refractory Periods

Refer to “PVC Response” on page 104 and “PMT Intervention” on page 102 for further details of the PVC Response and PMT Intervention features and their interactions with PVARP.

InSync Model 8040 Device Reference Guide

TARP TARP

SAV + PVARP

SAV

PVARP

SAV

Chapter 3

Refractory Periods

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 Interval – 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

– In the DDIR and DDI modes, the AV interval starts with the

■

Post-Ventricular Atrial Refractory Period (PVARP) –The PVARP is described earlier in this chapter.

interval is the AV interval.

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.

Figure 3-11. Total Atrial Refractory Period

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 74 for more information.

InSync Model 8040 Device Reference Guide

Ventricular Refractory Period

VRP

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 Activity Rate interval restarts.

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

Device timing

Refractory Periods

Figure 3-12. 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.

InSync Model 8040 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 Activity 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 Lower Rate for all nonrate-responsive modes.

InSync Model 8040 Device Reference Guide

Refractory Periods

Sensor-Indicated Interval

Parameters:

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

PAV Interval = 200 ms Ventricular Refractory Period = 240 ms

PVARP = 300 ms PVAB = 200 ms

Activity Activity Activity

Lower Rate

Parameters:

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

Ventricular Refractory Period = 240 ms

Sensor Activity

Figure 3-13. Example of Noise Reversion in DDDR at Sensor-Indicated Rate.

Device timing

Figure 3-14. Example of Noise Reversion in VVIR at Lower Rate.

InSync Model 8040 Device Reference Guide

Chapter 3

High Rate Atrial Tracking

Preventing Noise Sensing

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.

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:

■

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

■

Reprogram sensing to bipolar polarity (if available).

■

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

■

Remove patient from EMI environment.

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 Activity Rate also must be considered.

For heart failure patients, 2:1 block and Wenckebach operation should be avoided to prevent loss of cardiac resynchronization therapy.

InSync Model 8040 Device Reference Guide

2:1 Block

Device timing

High Rate Atrial Tracking

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 sensor-varied 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 Activity Rate exceeds the 2:1 block rate.

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.

InSync Model 8040 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

Activity

Upper Tracking

Rate Interval

Upper Tracking

Rate Interval

SAV

Interval

Chapter 3

High Rate Atrial Tracking

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

Figure 3-15. Example of Pacemaker Wenckebach Operation

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 Activity Rate (UAR) interval may interact at high atrial rates in the DDDR mode.

Tabl e 3-1. Upper Rates Interaction With TARP

Relationship Between TARP and Upper Rate

Intervals

InSync Model 8040 Device Reference Guide

TARP > both UAR and

UAR interval > TARP >

UTR interval > both UAR

Unless Non-Competitive Atrial Pacing is On; see “Non-Competitive Atrial Pacing” on page 99.

UTR intervals

UTR interval

UAR interval > UTR

interval > TARP

interval and TARP

Wenckebach

Before 2:1

Block

Achieve

Upper

Tracking Rate

no no yes

no no no

yes yes no

yes yes yes

Potential

Atrial

Competition

Lead/cardiac tissue interface

Selecting Pacing Parameters 78

Selecting Sensing Parameters 83

Monitoring Lead Stability 86

Transtelephonic Capture Verification with TMT 89

Chapter 4

Selecting Pacing Parameters

Overview

Pacing outputs (amplitude and pulse width) should be set high enough to guarantee reliable capture in the atrium and reliable biventricular capture in the ventricles, but not so high as to unnecessarily deplete the device battery. Whether selecting pacing outputs at implant or follow-up, the same considerations apply:

■

Select pacing polarity for leads

■

Determine pacing thresholds

■

Select appropriate outputs (pulse width and amplitude)

Selecting Pacing Polarity

If bipolar leads are used, Pacing Polarity for the atrial output and the ventricular outputs can be programmed to bipolar or unipolar.

■

Bipolar Pacing Polarity – 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 ECG.

■

Unipolar Pacing Polarity – The lead tip is the active electrode; the device case is the common electrode. Unipolar pacing produces large pacing artifacts that aid in ECG interpretation. However, it is more likely to cause muscle stimulation, especially at high pacing amplitudes.

Warning: No pacing output results when a unipolar lead is present and Pacing Polarity is programmed to bipolar. (An exception to this is the use of both a unipolar lead and a bipolar lead for biventricular pacing in the ventricles. The outputs for this ventricular unipolar/bipolar lead combination can be programmed to unipolar. See the following section “Ventricular Polarity Configurations”.

Ventricular Polarity Configurations

Since the programmed setting for polarity (Pacing Polarity or Sensing Polarity) is common to both ventricular leads (not independently programmable), special consideration should be given to the lead polarity configurations.

InSync Model 8040 Device Reference Guide

Two bipolar leads – Ventricular polarity can be programmed to either Bipolar or Unipolar. Both leads will function according to the programmed polarity setting.

Two unipolar leads – Ventricular polarity must be programmed to Unipolar. Both leads in this system can function only as unipolar leads. The Bipolar setting results in no pacing or sensing.

One bipolar lead and one unipolar lead – Ventricular polarity can be programmed to either Bipolar or Unipolar.

■

With the Unipolar setting, both leads operate as unipolar leads.

■

With the Bipolar setting, the ring electrode on the bipolar lead acts as the common electrode (current return path) for both leads. This configuration thus results in “shared-ring” bipolar pacing and sensing.

Bipolar Pacing Polarity Confirmation

Before programming from unipolar to bipolar pacing, the programmer verifies the presence of a bipolar lead by testing lead impedance for each lead. Testing is done under magnet operation for four seconds at an Amplitude of 5.0 V and a Pulse Width of

1.0 ms if the permanent settings are at or below this level. If permanent settings are above these values, the measurement will be made at the permanent settings.

■

If bipolar lead impedance is between 200 ohms and 3000 ohms, a bipolar lead is assumed to be present.

Note: Impedance for the ventricular two-lead system is measured across the parallel combination of both leads.

■

If bipolar lead impedance is outside this range, a unipolar lead 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.

Lead/cardiac tissue interface

Selecting Pacing Parameters

Warning: If the clinician overrides the bipolar lead verification routine and programs bipolar polarity when a unipolar lead is connected, no pacing output results.

InSync Model 8040 Device Reference Guide

Chapter 4

Selecting Pacing Parameters

Determining Stimulation Thresholds at Implant

At implant, use a Medtronic Pacing System Analyzer (PSA) to determine threshold values for capture. Refer to the PSA manual for detailed instructions.

Verifying Stimulation Thresholds at Follow-up

Medtronic programmers provide both automatic and manual threshold tests for determining the patient’s stimulation threshold at follow-up. Stimulation threshold resolution is determined by the available increments of amplitude and pulse width. Included with the automatic threshold test on the programmer is a strength-duration graph that shows voltage safety margins.

For a detailed description of the threshold tests and test procedures, refer to the InSync Model 8040 Device Programming Guide.

Measuring Stimulation Thresholds in the Ventricles

Special consideration should be given to measuring stimulation thresholds in the ventricles.

Output adjustment affects both leads – Adjusting amplitude and pulse width values during threshold measurement changes the output energy to both ventricular leads.

When the two ventricular leads have different thresholds –

When the two leads do not present the same energy requirement to maintain capture, it is important to determine the thresholds for the lead presenting the higher energy requirement. This is the biventricular threshold, the point above which both leads will maintain capture.

■

Measuring the biventricular threshold — During threshold measurement as device output is decreased in a step-by-step fashion, capture will be lost first by the higher-threshold lead, while the other lead continues to pace. For this reason, it is necessary to watch for changes in depolarization waveform morphology (rather than the complete loss of pacing capture) to identify the biventricular threshold point.

InSync Model 8040 Device Reference Guide

Lead/cardiac tissue interface

Output Settings (example):

Loss of Capture by One Lead

3.0 V

0.20 ms 0.15 ms 0.12 ms

Selecting Pacing Parameters

■

Recognizing loss of biventricular capture — The loss of biventricular capture in cases where the two ventricular leads exhibit different thresholds may cause a widening of the depolarization waveform as shown in the example below. Since such variables as lead placement and depolarization vectors can affect waveform shape, the actual morphology change will vary with each patient.

Figure 4-1. Illustrative Example of Capture Loss by One Lead

When both leads have the same threshold – In cases where

there is biventricular capture and both ventricular leads have the same threshold, there is only a single threshold point indicated by complete loss of ventricular capture.

Caution: The presence of a single ventricular threshold point also can indicate that biventricular capture was not present at the start of threshold measurement (only one lead is maintaining capture). In such cases, it may be advisable to conduct the threshold test again, starting at higher amplitude and pulse width test values to increase the likelihood that both leads are capturing at the start of the test.

Achieving reliable biventricular capture – When the two ventricular leads do not present the same energy requirement to maintain capture, amplitude and pulse width must be set to provide an adequate safety margin above the thresholds for the lead presenting the higher energy requirement. Without consistent capture by both ventricular leads, the benefits of biventricular pacing are lost.

InSync Model 8040 Device Reference Guide

Chapter 4

Selecting Pacing Parameters

Selecting Output Parameters

For Further Information

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 amplitudes and pulse widths that provide at least a 2:1 voltage safety margin.

■

To assure reliable biventricular capture in the ventricles, the voltage safety margin should be based on the threshold of the lead exhibiting the higher energy requirement.

■

When amplitudes greater than 2.5 V are required during the maturation phase of the lead(s), threshold(s) and output setting(s) should be carefully reevaluated at the first follow-up.

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 further information on device longevity under various pacing scenarios refer to “Longevity Projections (Normal Operating Life)” on page 202. For information on amplitude and pulse width parameter settings refer to “Programmable Modes and Parameters” on page 182. For information on crosstalk or self-inhibition refer to “Precautions” on page 212.

InSync Model 8040 Device Reference Guide

Selecting Sensing Parameters

Overview

Sensitivity determines the minimum intracardiac signal that the device can detect when intrinsic atrial or ventricular events occur. Whether selecting sensing parameters at implant or verifying sensing at follow-up, the same considerations apply:

■

Select sensing polarity for leads

■

Determine sensing thresholds

■

Select appropriate sensitivity settings

Selecting Sensing Polarity

Atrial and ventricular sensing polarities can be programmed for each chamber when used with bipolar leads.

■

Bipolar Sensing Polarity – The lead tip and the lead ring electrode are the poles of the sensing circuit. Because bipolar sensing is more localized, it reduces the likelihood of sensing myopotentials and electromagnetic interference. It may also permit sensitivity to be programmed to a more sensitive setting.

■

Unipolar Sensing Polarity – 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 with bipolar sensing. Oversensing due to myopotentials is more common with unipolar sensing than with bipolar sensing.

Lead/cardiac tissue interface

Selecting Sensing Parameters

Refer to “Ventricular Polarity Configurations” on page 78 for information about the ventricular two-lead system.

Bipolar Sensing Polarity Confirmation

Before programming from unipolar to bipolar sensing, the programmer verifies the presence of a functioning bipolar lead by testing impedance for the lead. operation for four seconds at an Amplitude of 5.0 V and a Pulse Width of 1.0 ms if the permanent settings are at or below this level. If permanent settings are above these values, the measurement will be made at the permanent settings.

Testing is done under magnet

InSync Model 8040 Device Reference Guide

Chapter 4

Selecting Sensing Parameters

■

If bipolar lead impedance is between 200 ohms and 3000 ohms), a bipolar lead is assumed to be present.

■

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

Warning: Do not override for an implanted lead. The override feature is intended only as a means to program the device for bipolar polarity before lead connection.

Determining Sensing Threshold(s) at Implant

At implant, use Medtronic Pacing System Analyzer (PSA) to determine sensing threshold values for the device. Refer to the PSA manual for detailed instructions.

Before connecting a 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.

The programmer warns that the

Verifying Sensing Threshold(s) at Follow-up

Intracardiac signal amplitudes decrease during the lead maturation process. Medtronic programmers provide an automatic sensitivity test that allows the follow-up clinician to verify a patient’s sensitivity settings. The automatic test provides for atrial or ventricular monitoring. The test provides the sensitivity setting just above and below the point at which P waves or R waves are sensed.

The cardiac signal presented to the device by the ventricular two-lead system is a composite signal from the parallel combination of both ventricular leads. The Sensing test treats this signal as a single input with a measurable amplitude that can be used to determine an appropriate setting for ventricular sensitivity. Conducting the Sensing test for the ventricular two-lead system does not require any special considerations.

Impedance for the ventricular two-lead system is measured across the parallel combination of both leads.

InSync Model 8040 Device Reference Guide

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 an atrial sensing test to determine the appropriate atrial 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 polarity 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 sensitivities 1.0 mV or 1.4 mV with wide atrial pulse widths or high atrial amplitudes may result in Ventricular Safety Pacing (if 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.

Lead/cardiac tissue interface

Selecting Sensing Parameters

For Further Information

In the PSA manual, refer to sensitivity threshold test procedures. Refer to “Noise Reversion” on page 72 for a description of noise reversion operation. Refer to “Programmable Modes and Parameters” on page 182 for sensitivity parameter settings.

InSync Model 8040 Device Reference Guide

Chapter 4

Monitoring Lead Stability

Overview

The Lead Monitor feature periodically measures the pacing impedance of each lead. It is intended for troubleshooting when an intermittent lead problem is suspected. The Lead Monitor also has an optional Polarity Switch feature that can automatically reprogram polarity from bipolar to unipolar for each lead. It is intended to support backup unipolar pacing and sensing in the event of a bipolar lead failure.

The Lead Monitor is available in all pacing modes. It is not recommended to use Lead Monitor with single chamber triggered modes (VVT and AAT).

Caution: If the Lead Monitor detects out-of-range lead impedance, investigate lead integrity more thoroughly.

Warnings:

■

Programming Lead Monitor with the optional polarity switch is contraindicated for patients with implantable defibrillators. When an out-of-range lead is detected, the monitor automatically reprograms the selected leads to unipolar polarity. Pacing in the unipolar configuration may either provoke inappropriate therapy or withhold appropriate therapy.

Do not program Lead Monitor on prior to implanting the device in the patient. With no leads connected, lead impedance is infinitely high and determined by the device to be out-of-range. If the device has been programmed to switch polarity, the resulting unipolar condition will not support pacing until the device is placed in the pocket, thereby completing the circuit.

Note: The Lead Monitor is automatically disabled if the elective replacement indicator (ERI) is tripped.

How the Monitor Works

Impedance for each active lead is measured every three hours. The measurement requires up to three pacing cycles during which Amplitude and Pulse Width change to 5.0 V and 1.0 ms, respectively, if the permanent settings are at or below this level. If permanent settings are above these values, the measurement will be made at the permanent settings.

InSync Model 8040 Device Reference Guide

■

Sustained intrinsic activity may prevent measurement from occurring.

■

If a lead impedance measurement falls outside the range of 200 to 3000 ohms, the Lead Trend diagnostic (described below) is automatically activated.

Note: Impedance for the ventricular two-lead system is measured across the parallel combination of both leads.

How the Polarity Switch Works

The polarity of the selected bipolar lead is automatically reprogrammed by the device from bipolar to unipolar if the lead impedance measurement is outside the range of 200 to 3000 ohms. Programmable options for Polarity Switching are:

■

atrium and ventricle (the atrial and ventricular polarity switch to unipolar)

■

atrium (only the atrial polarity switches to unipolar)

■

ventricle (only the ventricular polarity switches to unipolar)

Recording a Lead Trend

Lead/cardiac tissue interface

Monitoring Lead Stability

The Lead Trend attempts to measure and log the impedance of each active lead every three days. Lead impedance data collection is the same as for the Lead Monitor.

■

The device can collect up to 720 days of lead impedance data for single chamber configurations and 360 days of data for dual chamber configurations.

■

Lead Trend is automatically activated when the Lead Monitor detects an out-of-range lead.

Figure 4-2 shows how the Lead Trend report is presented on the programmer. The report can be printed out or displayed on the programmer.

InSync Model 8040 Device Reference Guide

Chapter 4

Monitoring Lead Stability

Overriding Other Diagnostics

Figure 4-2. Example of Lead Trend Diagnostic

If the Lead Trend is activated because the Lead Monitor detects out-of-range lead impedance, any programmed diagnostic is disabled, and its data are overwritten by Lead Trend data.

For Further Information

Refer to the InSync Model 8040 Device Programming Guide for information on configuring the Lead Trend diagnostic and collecting its data.

InSync Model 8040 Device Reference Guide

Lead/cardiac tissue interface

DDD Operation

Magnet Applied

Threshold Margin Test

Rate = 100 ppm

Asynchronous (DOO) Pacing Rate = 85 ppm

Parameters:

Mode = DDD PAV = 180 ms

Lower Rate = 60 ppm

Pulse Widths Reduced by 25%

PAV = 100 ms

Transtelephonic Capture Verification with TMT

Overview

During transtelephonic monitoring, the Threshold Margin Test (TMT) provides a check for loss of capture at 25% reduced pulse width(s). The TMT may indicate that loss of capture is possible but cannot verify that safety margin is adequate.

Warning: Loss of capture during TMT indicates that the pacing safety margin is inadequate. Have the patient come to the clinic as soon as possible for threshold evaluation and reprogramming of outputs for a 2:1 voltage safety margin. Imminent loss of ventricular capture for a pacemaker-dependent patient may constitute an emergency situation.

Dual Chamber TMT Operation

Applying the magnet over the device initiates a Threshold Margin Test (TMT). As shown in Figure 4-3, the device delivers three asynchronous AV sequential pulses at a rate of 100 ppm with a paced AV interval of 100 ms. The first two sequences of pulses are delivered at the programmed Pulse Widths. The third sequence is delivered at a 25% reduction of the programmed Pulse Widths.

Figure 4-3. Dual Chamber TMT Operation

InSync Model 8040 Device Reference Guide

VVIR Operation

Magnet Applied

Threshold Margin Test

Rate = 100 ppm

Parameters:

Mode = VVIR

Pacing Rate = 60 ppm

Pulse Widths Reduced by 25%

Chapter 4

Transtelephonic Capture Verification with TMT

Single Chamber and VDD Mode TMT Operation

Applying the magnet over the device initiates TMT. As illustrated below for ventricular operation, the device delivers three asynchronous pulses at a rate of 100 ppm. The first two pulses are delivered at the programmed Pulse Width. The third pulse is delivered at a 25% reduction of the programmed Pulse Width.

Figure 4-4. Single Chamber and VDD Mode TMT Operation

Enhanced Transtelephonic Monitoring

The Transtelephonic Monitor is a programmable On or Off feature intended for use with remote device monitoring services. Programming the feature Off does not affect conventional transtelephonic monitoring.

When the Transtelephonic Monitor is programmed On, the device delays the Threshold Margin Test for five seconds upon magnet application to enhance communication with transtelephonic equipment. If the pacing polarity is permanently programmed to bipolar, it is temporarily set to unipolar to provide improved ECG artifact detection for the remote monitoring equipment. The programmed polarity is restored when the magnet is removed.

When Transtelephonic Monitor is programmed Off, the Threshold Margin Test is not delayed upon magnet application, and conventional transtelephonic monitoring can occur.

InSync Model 8040 Device Reference Guide

Warning: Programming Transtelephonic Monitor On is contraindicated for patients with implantable defibrillators. When it is programmed On, the pacing polarity is temporarily set to unipolar when the magnet is applied. Pacing in the unipolar configuration may cause the defibrillator to provoke inappropriate therapy or withhold appropriate therapy.

For Further Information

Refer to the InSync Model 8040 Device Programming Guide for programming instructions regarding Transtelephonic Monitor.

Lead/cardiac tissue interface

Transtelephonic Capture Verification with TMT

InSync Model 8040 Device Reference Guide

Special therapy options

Mode Switch and Diagnostic 94

Non-Competitive Atrial Pacing 99

PMT Intervention 102

PVC Response 104

Ventricular Safety Pacing 107

Rate Drop Response 108

Sleep Function 113

Single Chamber Hysteresis 115

Chapter 5

Mode Switch and Diagnostic

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. It has a programmable Detect Rate for when to mode switch. Mode Switch is not recommended for patients known to have chronic refractory atrial tachyarrhythmias: atrial tachycardia, atrial fibrillation, or atrial flutter.

When the device detects an atrial tachyarrhythmia, it switches from the programmed atrial tracking mode to a non-atrial tracking mode until the atrial tachycardia ceases, see Figure 5-1.

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. See “Device Programming Recommendations” on page 178.

Atrial Tracking Mode Non-Atrial Tracking Mode

DDDR DDIR

DDD DDIR

VDD VVIR

Figure 5-1. Mode Switching Modes

How the Device Defines Atrial Tachycardia

The device defines an atrial tachycardia based on the mean atrial rate and the programmable Detect Rate:

Mean atrial rate (MAR) – A running average calculated from all A-A intervals (except AS-AP and AR-AP). To respond quickly to the onset of atrial tachycardia, the MAR increases rapidly by giving preference to shorter A-A intervals. For longer A-A intervals, the MAR decreases gradually to ensure that atrial tachycardia has stopped.

InSync Model 8040 Device Reference Guide

Detect Rate – The rate at which device-defined atrial tachycardia

Ensuing atrial tachycardia, interval is about 190 ms

Mode switch from DDDR to DDIR

Ventricular interval at 500 ms

Ventricular interval increases by 40 ms each VP

starts. 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.

When the MAR exceeds the Detect Rate, atrial tachycardia is considered in progress. When either the MAR drops below the Upper Tracking Rate or five consecutive atrial paces occur, the atrial tachycardia is considered to have ceased.

Mode Switch Operation

When the device detects an atrial tachycardia in the DDDR, DDD, or VDD mode, it switches to the appropriate non-atrial tracking mode in approximately 15 seconds. To avoid an abrupt drop in the ventricular rate, it smoothly reduces the pacing rate from the atrial synchronous rate to the sensor-indicated rate in approximately

2.5 minutes, see Figure 5-2. After the rate transition is completed, the device continues

sensor-driven pacing in the ventricle, operating in the non-atrial tracking mode until the atrial tachycardia ceases.

Special therapy options

Mode Switch and Diagnostic

Figure 5-2. Mode Switching to Non-Atrial Tracking Mode

When the device determines that the atrial tachycardia has ceased, it begins to switch back to the programmed atrial tracking mode.

InSync Model 8040 Device Reference Guide

Chapter 5

Mode Switch and Diagnostic

Mode Switching Interruption

DDDR and DDD Modes – Abrupt changes in ventricular rate are

avoided by smoothly varying the pacing rate until the A-A interval corresponds to the mean atrial rate. At that point, the device switches to the programmed mode.

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

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

■

the atrial tachycardia episode ceases before the device completes the rate transition to the appropriate non-atrial tracking mode or

■

the atrial tachycardia 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.

Preset Parameter Settings

When Mode Switch is programmed On, several parameters are automatically set to the following values:

■

Upper Activity Rate is set equal to the Upper Tracking Rate.

■

Post-Ventricular Atrial Blanking and Rate Adaptive AV are set to values based on the programmed Upper Tracking Rate.

■

Post-Ventricular Atrial Refractory Period is set to a value based on the programmed Detection Rate.

■

Rate Drop Response is set to Off.

The values selected are necessary for proper mode switching operations.

InSync Model 8040 Device Reference Guide

Recording Mode Switch Episodes

Mode switch episodes are always counted, and the total is presented in the Event Summary report. (See “Event Summary” on page 138). Additional details for up to 14 mode switch episodes can be recorded by the programmable Mode Switch Episode diagnostic. Two recording methods are available:

■

The Frozen method collects detailed data for the first 14 episodes detected.

■

The Rolling method collects detailed data for the most recent 14 episodes, overwriting older data if necessary.

For each of the 14 mode switch episodes, the device records the following data:

■

date and time of occurrence

■

episode duration (in minutes)

■

approximate atrial rate (Tachy Rate)

■

rates of 24 events associated with the mode switch episode, as follows:

– the last 8 events preceding the mode switch,

– the first 8 events of mode switch operation, and

– the first 8 events after return to permanent mode.

Special therapy options

Mode Switch and Diagnostic

Figure 5-3 shows how mode switch episodes are summarized on the programmer. Figure 5-4 shows how the programmer presents detailed data for a selected episode. All reports can be printed out or displayed on the programmer.

InSync Model 8040 Device Reference Guide

Chapter 5

Mode Switch and Diagnostic

Figure 5-3. Example of Mode Switch Episodes Diagnostic

Figure 5-4. Example of Detailed Data for a Selected Mode Switch

Episode (Diagnostic)

InSync Model 8040 Device Reference Guide

Erasing Mode Switch Episode Data

Certain programmer functions erase stored Mode Switch Episode data. Review or print episode data before performing any of the following functions:

■

programming another diagnostic,

■

using the programmer “Clear Data” command, or

■

initiating an activity threshold test or exercise test.

Note: The Mode Switch Episode diagnostic is disabled and all episode data erased if the Lead Monitor enables the Lead Trend diagnostic. See “Monitoring Lead Stability” in Chapter 4 for more information on this feature. Episode data collection is suspended if the elective replacement indicator is set, but data already collected are retained.

For Further Information

Refer to the InSync Model 8040 Device Programming Guide for information on configuring the Mode Switch Episode diagnostic and collecting its data.

Special therapy options

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 mode only.

Note: NCAP should be programmed On for heart failure patients.

How NCAP Affects Atrial Timing

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.

InSync Model 8040 Device Reference Guide

100

Pace Atrium safely, no capture

Relative refractory period, atrial pace may induce atrial tachycardia

Pace Atrium safely, capture

Chapter 5

Non-Competitive Atrial Pacing

■

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.

Figure 5-5. The Atrium’s Relative Refractory Period

How NCAP Affects Ventricular Timing

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 80 ms. When a relatively high Lower Rate and long PVARP are programmed, NCAP operation may result in ventricular pacing slightly below the Lower Rate.

InSync Model 8040 Device Reference Guide

Medtronic 8040 Reference Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Required Physician Training

How to Use This Guide

Contents

1 Pacing modes 13

2 Rate response 35

3 Device timing 49

4 Lead/cardiac tissue interface 77

5 Special therapy options 93

6 Telemetry data 117

7 Miscellaneous operations 127

8 Diagnostics 135

9 Troubleshooting the device system 151

A Device description 165

B Preset parameter settings 169

C Device programming recommendations 177

D Parameter values and restrictions 181

E Telemetry and diagnostic values 195

F Longevity projections 201

G Warnings, precautions, and EMI 205

H Clinical Studies 225

I Glossary 227

Index 233

Understanding device operation

Pacing modes

Introduction

Pacing Mode Selection

NBG Pacing Codes

Further Information

Mode Pertinency Tables

Indications and Usage

Contraindications

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

Rate response

Introduction to Rate Responsive Pacing

Overview

Sensor-Indicated Rate

Typical Rate Response Settings

Activity Threshold

Overview

How Activity Threshold Influences Rate

Evaluating the Activity Threshold Setting

Typical Rate Performance

Activity Rate Response

Overview

Basic Operation

Determining the Steady-State Pacing Rate

Acceleration and Deceleration Times

Overview

Acceleration Operation

Deceleration Operation

Exercise Deceleration Operation

Rate Response Optimization

Overview

Rate Response Optimization Operation

Programming Considerations

Reporting Rate Response Parameter Changes

Recording Rate Response Optimization Events

Possible Loss of Diagnostic Data

Device timing

Rates

Overview