AccuPace Series 4800 Instruction Manual

TABLE OF CONTENTS Specifications - Pacing Tests

iii iv

Panel Controls and Display - Figure 1

v

Key to Analyzer Controls

vi

International Classifications and Certifications

ix

General Description

1

Accessory Cables - Connection and Care 2 Key to Status Indicators - Figure 2

3

Indications, Contraindications, Warnings, and Potential Complications

4

Programmable Modes and Parameters

7

Single Chamber Modes Dual Chamber Modes Basic Rate Pulse Amplitude Pulse Width Sensitivity AV Delay

7 7 8 9 9 9 10

Non-Programmable Parameters

11

PV Delay Refractory Periods Maximum Tracking Rate Blanking Period Ventricular Safety Pacing PVC Response PMT Limit PMT Termination Algorithm

11 11 12 12 12 12 12 13

General Operations

14

Power On/Off Special Features Nominal (Standard) Value Pacing STAT (Emergency) (DDI) Pacing Inhibit A / Inhibit V Temporary Maximum Output Menu Operations

14 14 15 15 15 16 17

Atrial and Ventricular Capture Data Audio Patient ID View Archive Information

i

17 17 17 17

TABLE OF CONTENTS, Continued Date and Time Adjusting Nominal Parameters Display Light

18 18 18

Connection to Pacing Leads

19

Bipolar Configuration Uniploar Configuration

19 19

Programming

20

Changing Mode Changing Parameter Settings Changing Parameters Displayed Rapid Atrial Stimulation

20 20 20 21

Test Functions

22

Measuring Stimulation Threshold Measuring P Wave and R Wave Amplitude and Slew Rate Measuring Lead Impedance and Current Delivered Measuring Retrograde (VA) Conduction Storing and Clearing Data Print-out Format - Figure 3

22 22 22 23 23 25

Safety Features

26

Effects of Defibrillation and Electrosurgical Devices

26

Normal Maintenance - Cleaning and Disinfecting

26

Low Battery Indicator and Replacement

27

Service

27

Storage

28

AccuPace Accessories

28

Warranty

29

Product Disposal

29

Physical Specifications - Analyzer

30

ii

SPECIFICATIONS PACING PARAMETERS AND VALUES Values

Nominal/STAT

Steps/Units

DDD, DDI, DVI, VVI and AAI

---/DDI

N/A

30 - 180ppm 30 - 180ppm 30 - 180ppm

70/--70/--60/60

1 ppm 1 ppm 1 ppm

Rapid Stimulation¹

60 - 990ppm

100/---

10 ppm

Pulse Amplitude² (A&V)

0.1 - 10.0V

3.5/10.0

0.1V

(A&V)

0.05 - 1.0ms 1.0 - 2.0ms

0.40/1.5

0.05ms 0.1ms

(Atrial) (Ventricular)

0.5 - 10.0mV 1.0 - 10.0mV 10.0 - 20.0mV

1.0/1.0 2.0/2.0

0.5mV 0.5mV 1.0mV

Refractory Period¹ (Nominal) (Dual Chamber/High Rates)

250 or 330ms 200 - 330ms

250/250

Auto Pgmd Auto Pgmd

AV Delay¹

15 - 300ms

150/150

1.0ms

PV Delay¹

*AV delay minus 25ms

125/---

Auto Pgmd

Maximum Tracking Rate¹

40ppm > Rate

100/---

Auto Pgmd

Ventr. Blanking Period¹

30ms

30/30

Fixed

Ventricular Safety 1 Pacing

120ms

Enabled

Fixed

1

40bpm > Rate

100/---

Auto Pgmd

PMT Term. Algorithm

10 Beats > PMTR

10/---

Fixed

PVC Response

1 cycle DVI

Enabled/---

Fixed

Parameter Modes:

Demand:

Asynchronous: DOO, VOO, AOO Basic Rates¹

(Atrial) (Ventricular) (Dual)

³3

Pulse Width

Sensitivity

PMT Limit

4

*Gradually reduces below 50ms AV delay to a minimum of 15 ms. Refer to discussion on page 11. ------------------------------------------------------------------------------------------------------------Specifications @ 20°C ± 2°C with 500 Ohm ± 1% load: 1 = ± 1 - 5%

2 = ±10%

3 = the greater of ± 10% or 0.05V

iii

4 = ± 20%

TEST SPECIFICATIONS

Range

Patient/Lead System Tests

Increment

50 - 2000 Ohms * Stimulation Impedances1 w/ Outputs < 1.0 Volts and/or PW < 0.10ms

1 Ohm

50 - 4000 Ohms * Stimulation Impedances1 w/ Outputs > 1.0 Volts and PW >= 0.10ms

1 Ohm

P Wave Amplitude 2

0.01mV 0.1mV

R Wave Amplitude 2

0.5 - 9.99mV 10.0 - 20.0mV 1.0 - 9.99mV 0.01mV 10.0 - 20.0mV

0.1mV

** Capture Thresholds Pulse Amplitude *

0.10 - 10.0V

0.1V

Pulse Width *

0.05 - 0.95ms 1.0 - 2.0ms

0.05ms 0.1ms

Retrograde Conduction³

180 - 600ms

1.0ms

Slew Rates ²²

0.05 - 5.00V/S

0.01V/S

Resultant Current (atrial or ventricular)

0.1 - >100.0mA

0.1/1.0mA

Accuracy: ¹ = > 0.1 ms ± 20% ² = ± 15% ²² = ± 20% ³= ± 5% ³³ = ± 10% < 0.1 ms ± 30% *Current programmed values are recorded into memory as the Capture Thresholds when the STORE CAPTURE key is pressed.

CAUTION: Variations in test methodology exist between manufacturers of implantable pacing systems as well as analyzers. It is recommended that the user of an AccuPace maintain a record of the values measured by both devices at implant, initially, so that an assessment of repeatability and acceptability may be made.

* Stimulation impedances are reported at the programmed pulse amplitude and pulse width. **Capture thresholds are performed and reported at user selected pulse amplitude and pulse width.

Note: Nominal factory rate settings when turned on are 70 ppm for single chamber modes and 60 ppm for dual chamber modes. When initially energized rate settings are 30 ppm, or if using the RESUME ON key, the device will operate in the last operating condition.

iv

AccuPace™ PACING ANALYZER DETAIL

Output Terminal(s) Atrial Ventricular Infrared Window

Parameter Control Keys

Special Function Keys

Test Control Keys

LCD Display

Mode Control Keys

Figure 1

v

Change Wheel

Print Control Key

KEY TO ANALYZER CONTROLS Pacing Parameter Controls:

CHANGE VALUE

Changes the value of the selected parameter; selected parameter is indicated on the display by the cursor.

RAT E

Selects Rate parameter for change.

A-V DELAY

Selects AV Delay parameter for change; dual-chamber modes only.

OUT PUT AM PL

Selects Output Amplitude parameter for change; selects A or V output depending on the lead currently displayed.

PULSE WIDT H

Selects Pulse Width parameter for change; selects A or V pulse width depending on the lead currently displayed.

SENSE

Selects Sensitivity parameter for change; selects A or V sensitivity depending on the lead currently displayed.

Pacing Mode Controls: ASYNCH DEM AND

Changes pacing mode between asynchronous and demand (inhibited) operation: Asynch Demand AAI AOO VVI VOO DVI DOO DDD DOO DDI DOO

AAI ON

Turns unit on in AAI (atrial inhibited) mode at nominal settings, except rate, which will be 30 ppm. If unit is on, changes mode to AAI at current settings.

VVI ON

Turns unit on in VVI (ventricular inhibited) mode at nominal settings, except rate, which will be 30 ppm. If unit is on, changes mode to VVI at current settings.

DVI ON

Turns unit on in DVI (AV sequential inhibited) mode at nominal settings, except rate which will be 300ppm. If unit is on, changes mode to DVI at current settings.

DDD ON

Turns unit on in DDD (AV universal) mode at nominal settings, except rate which will be 30 ppm. If unit is on, changes mode to DDD at current settings.

ST AT (DDI)

Turns unit on in DDI (atrial and ventricular inhibited) mode at maximum output. If unit is on, changes mode to DDI at maximum output. Emergency mode to re-establish capture, if possible, without repositioning lead.

KEY TO ANALYZER CONTROLS, Continued vi

Special Pacing Controls: M AX OUT PUT

INHIBIT A-OUT INHIBIT V-OUT

Temporarily changes pacing output to maximum (10V @ 2ms) on lead currently displayed, as long as key is held. Turns off atrial output if present in current pacing mode. Pressing this key again will restore atrial output. Turns off ventricular output if present in current pacing mode. Pressing this key again will restore ventricular output.

RAPID AT RIAL

Selects Rapid Atrial Rate parameter for change. key.

PACE RAPID

Initiates rapid atrial pacing as long as key is held. The Rapid Atrial key must be pressed first to enable Pace Rapid.

Enables the Pace Rapid

Immediately changes all pacing parameters in the current mode to nominal NOM INAL settings.

RESUM E Turns unit on in the same pacing mode, same settings, and the same patient ON data as when it was last turned off.

Lead Test Controls: LEAD Press and hold to measure impedance and current for lead currently MEASURE displayed. Updates measurement on each pacing output. Release to save last measurement taken.

RETRO (VDI) Press and hold to test for retrograde conduction; unit will change to VDI mode (VVI with atrial sensing) at a rate of 100 ppm or programmed rate if MEASURE greater. Hold key until test results appear on the display. Normal operation will resume when test ends or the key is released. CAPTURE Press to store the currently displayed output settings as the capture Amplitude and pulse width settings will be saved on display and in memory. Pacing output for the lead under test will return to nominal settings.

ST ORE threshold.

P / R WAVE Press and hold to measure amplitude and slew rate of the sensed signal on the lead currently displayed. Temporarily changes sensitivity to maximum. MEASURE Updates measurement on each sensed event. Release to save last measurement taken.

vii

KEY TO ANALYZER CONTROLS, Continued

System Controls: AT RIAL VENT R

M ENU

Selects which lead parameters are to be displayed. A legend appears on the display to denote the selected lead. Output amplitude, pulse width, sensitivity, and all measured lead parameters are displayed for the selected lead. Selects and deselects menu mode. In menu mode, special functions menu appears on the bottom line of the display. Change value wheel scrolls through available functions (refer to other sections of this manual).

In menu mode, accepts currently displayed option and advances the function CONFIRM to the next level (refer to other sections of this manual).

PRINT DAT A

Initiates the Print Data sequence to download data to remote printer. Allows selection of current or archive data.

CLEAR DAT A

Clears out any current lead data (both leads) and patient ID data is not lost, but is moved to archive and may still be printed.

OFF

Turns unit off and saves all pacing settings, patient ID, and lead data. Data will not be lost thereafter, even if batteries are removed.

viii

INTERNATIONAL CLASSIFICATION AND CERTIFICATIONS

The AccuPace Pacing Analyzer has been tested to ensure compliance with the intent of Directive 89/336/EEC for Electromagnetic Compatibility. Compliance was demonstrated to the following specifications as listed in the Official Journal of the European Communities: EMC Directive 89/336/EEC: EN 55011 EN 61000-4-3 EN 61000-4-2

Class B Radiated Emissions RF Electromagnetic Field Immunity Electrostatic Discharge Immunity

_____________________________________________________________________ The AccuPace is classified as a Type CF defibrillation-proof applied part and bears the international symbol identifying it as such shown below:

_____________________________________________________________________

The AccuPace bears the CE Mark to indicate its compliance with the requirements of Annex I of Council Directive 93/42/EEC, known as the "Medical Device Directive".

0086

ix

GENERAL DESCRIPTION The AccuPace Pacing Analyzer is an internally powered, softwareprogrammable device designed for continuous operation in the acute cardiac-care environment as both a temporary cardiac pacemaker and a Pacing Analyzer. Extensive multi-parameter, multi-mode programmability is particularly desirable during the primary implantation of a permanent pulse generator where the ability to mimic the implantable device as closely as possible can have great short-term and long-term significance. The AccuPace Pacing Analyzer is a constant voltage output device, capable of operating in all of the commonly utilized pacing modes from ventricular or atrial asynchronous (VOO or AOO) to AV Universal (DDD) pacing. In addition, those pacing parameters that may need to be adjusted to suit the specific needs of a patient, may be varied over a broad range, yet in increments, fine or coarse, which are more physiologically or diagnostically appropriate to that portion of the range of values. Programmable parameters include: rate, sensitivity, pulse amplitude, pulse width, and AV delay. Additional non-programmable parameters of interest include: maximum tracking rate which varies with rate, blanking period, ventricular safety pacing, PVC response, and a pacemaker-mediated tachycardia (PMT) termination algorithm. Also, the AccuPace Pacing Analyzer incorporates several additional features to simplify and broaden application. These include, among others: 1) a memory function to allow the storage and subsequent retrieval and printing of previously programmed data and measured information via an infrared (IR) link, 2) instant ON in any desired inhibited mode, 3) immediate output inhibition and recovery with the press of a key, 4) continuous display of pacing status and test data, 5) a backlit liquid crystal display (LCD), 6) non-volatile memory, and 7) a temporary maximum output key. The display of the AccuPace is configured to provide the user with all the information that may be required to perform the operations necessary to use the device either as a stimulator or a Pacing Analyzer. Legends, mode, parameter values, and test results are all displayed in a clear and concise manner. The AccuPace keypad and display format are shown in Figure 1. The case of the device is fabricated of durable ABS plastic. A sealed keypad and a Control Wheel are used to access and perform all functions of the analyzer, largely eliminating the potential for failure of mechanical switches. Additionally, the keypad provides a higher degree of resistance to fluid intrusion than is customarily found in conventional electronic devices. The AccuPace, along with batteries and cables (Pace Line cables are provided with the Models 4800 and 4802 only), is supplied in a rugged, soft pack carrying case. When not in use, it is recommended that the AccuPace always be stored in its carrying case to protect it from accidental damage with batteries removed. Finally, the AccuPace is fully electrically isolated. The circuit is protected from damage due to normal cardioversion and defibrillatory discharges, and the risk of output inhibition caused by detection of environmental EMI is limited by special shielding and signal filtering. WARNING: As with any critical medical device, it is of the utmost importance that an AccuPace be maintained in excellent operating condition. Any device that shows evidence of damage, defect or failure to operate in accord with any of its specifications should be promptly removed from service and returned to the company for repair and retesting. Serious adverse effects may be associated with the use of an impaired medical device. Damaged extension cables should be promptly replaced.

1

ACCESSORY CABLES - CONNECTION AND CARE The Model 4800 is supplied with two Pace Line™ extension cables, Model 4280 Series. The series of Pace Line autoclavable cables has a molded fixed pin connector with protected boots at the proximal end (device end) that fit directly into the output terminals of the device. For Model 4801, please refer to the cable manufacturer’s guide for connecting the cables to the adapter. The adapter and cables are not supplied by Pace Medical or APC Medical. The AccuPace 4801, is designed to accept a unique 6 pin male Redel® connector adapter which connects directly to the single 6 pin female Redel output connector on the AccuPace. The Atrial and Ventricular channels are marked on the distal end of the adapter for connection to patient cables. The Model 4802 is supplied with two Pace Line extension cables, Model 5280 Series. This series of Pace Line autoclavable cables have a unique 2 pin male Redel connector at the proximal end (device end) that fit directly into the output terminals of the device. Attention: For Pace Line cables only. One of the cables is labeled “Atrium”, the other cable is labeled “Ventricle”. This aids in the identification of the cables during dual-chamber procedures. The proximal end of each cable has a molded fixed pin connector or a unique 2 pin male Redel connector which will fit directly into the output connector of the AccuPace. The insulated alligator clips on the distal end provide a secure means of attachment to the temporary or permanent pacing leads. Instructions for Use With the Model 4800 off, connect the cables by unscrewing the terminal caps completely and inserting the connector pins of each extension cable into the terminals until fully seated. Observe polarity and ensure that the appropriate (atrial or ventricular) cable is in each terminal pair. Tighten terminal caps finger-tight only. Do Not Over-Tighten. At the distal end, the terminating alligator clips are also labeled as to channel and polarity. With the Model 4801 off, connect adapter by inserting the unique 6 pin Redel connector of the adapter into the terminal on top of the AccuPace until fully seated. Attach Atrial and Ventricular patient cables to the adapter. Ensure that the appropriate (atrial or ventricular) cable is in the properly labeled position on the adapter terminal. With the Model 4802 off, connect the Pace Line cables by inserting the unique 2 pin Redel connector, of each extension cable into the terminals until fully seated. Ensure that the appropriate (atrial or ventricular) cable is in each terminal. At the distal end the terminating alligator clips are also labeled as to channel and polarity. Sterilization Before use, the Pace Line cables may be cleaned with mild detergent and water, rinsed and sterilized by autoclaving using a standard U.S. Pharmacopoeia cycle of 15 minutes at a temperature of 121oC or the British Pharmacopoeia cycle of 30 minutes at 115°C. CAUTION: Extension cables which are repeatedly autoclaved should be periodically examined to ensure that there is no diminishment of the integrity of the cable with respect to its outer insulation and the resistance of the conductors (< 2 ohms). A cable showing any signs of physical deterioration should be promptly replaced.

2

KEY TO STATUS INDICATORS A = Issuance of Atrial Output Pulse

V = Issuance of Ventricular Output Pulse

P = Atrial Channel Sensing Event

R = Ventricular Channel Sensing Event

N = Electromagnetic Interference (EMI)

S = Device is Performing Ventricular Safety Pacing

W= Electronic Wenckebach is Being Performed in the Presence of a High Atrial Rate

B = 2:1 or Higher AV Block is Being Performed in the Presence of a High Atrial Rate

• = Signal Detected in the Refractory Alert Period; See Discussion on Page 8. Figure 2.

L = Low Batteries; Prompt Replacement Recommended.

3

INDICATIONS, CONTRAINDICATIONS, WARNINGS AND POTENTIAL COMPLICATIONS

NOTE: If an AccuPace has been exposed to very warm or very cold temperatures during transport, it should be allowed to come to room temperature prior to use.

Indications The AccuPace Pacing Analyzer is intended for use in the following circumstances: 1. To provide multi-modal and multi-parameter stimulation capability during Implant or revision of a permanent cardiac pacing system. 2. To provide a means for assessing the characteristics of implanted lead systems. 3. To provide a means for the printing out of data, including measured data, stored in memory. 4. To provide a means for delivering rapid atrial stimulation should it be needed during the course of implant or permanent pacing system revision. 5. To provide a means for assessing whether retrograde (VA) conduction is present in a patient and a measurement of the VP interval. Contraindications There are no known contraindications to the use of a normally functioning pacing analyzer when properly applied for the indications listed above. Warnings: A patient should be continuously monitored and attended while a pacing analyzer is pacing a patient. Cardiac pacing leads or heart wires provide a direct electrical pathway to the heart. Strict attention to electrical safety practices must always be observed when performing cardiac pacing procedures in the presence of line-powered monitoring or other support equipment as even minute alternating leakage currents flowing through the heart may induce ventricular fibrillation. The means for prompt resuscitation of a patient should always be close at hand. This Pacing Analyzer is intended for use with bipolar lead systems. Use with unipolar configurations may require the use of independent indifferents. See "Connection to Pacing Leads", page 19. The AccuPace Pacing Analyzer is a sophisticated electronic instrument, designed and manufactured to the highest standards. Nevertheless, as is typical of any such device, random component failure, damage due to mishandling, and battery depletion may limit its ability to perform in accord with its specifications. See also Potential Complications, below, and the warning on page 1.

4

INDICATIONS, CONTRAINDICATIONS, WARNINGS AND POTENTIAL COMPLICATIONS, Continued

Warnings, Continued: The AccuPace Pacing Analyzer must NOT be subjected to sterilization processes: EtO, gamma, or steam. The AccuPace is NOT designed to be immersed in cleaning or disinfecting solutions. Environmental electromagnetic interference, particularly that due to the proximate use of electrocautery / electrocoagulation devices, is known to interfere with the operation of pulse generators operating in a sensing mode. If the AccuPace detects electromagnetic interference, one or more of the following responses may be seen: output inhibition, interference rate operation, and / or tracking operation, if the AccuPace is programmed to DDD mode. Refer to page 24 for further discussion. When handling indwelling leads, the terminal pins or exposed metal conductive elements must not be touched or allowed to come into contact with electrically conductive or wet surfaces. Before handling an external pulse generator, patient cable(s), or indwelling lead(s), steps should be taken to equalize the electrostatic potential between the user and the patient; e.g. by touching the patient at a site remote to the pacing lead. Potential Complications The AccuPace Pacing Analyzer, in good operating condition, and used in accord with its instructions, will provide effective service as a means of evaluating important pacing parameters at the time of primary implant of a permanent pacing system or at subsequent revision, while at the same time providing pacing support to the patient as may be required. Nevertheless, certain environmental influences, ex. detected EMI, random component failure, and malfunctions associated with misuse or inadvertent damage to any device intended for use in maintaining an adequate, regular heart rhythm, may produce a limited number of potential complications. Among these are: 1.

Failure to provide adequate support for the patient due to the loss of a properly timed output pulse and attendant bradycardia or asystole.

2.

Failure of proper detection of the patient's intrinsic depolarization signal, resulting in pacemaker competition and arrhythmias, or intermittent output inhibition and bradycardia or asystole.

3.

Failure to provide a minimum necessary heart rate due to an inability to produce a stimulus of sufficient strength or duration, resulting in loss of capture and bradycardia or asystole.

4.

Failure of proper timing of output pulses resulting in an unanticipated, high rate or low rate of pacing which the patient may be unable to tolerate.

5

INDICATIONS, CONTRAINDICATIONS, WARNINGS AND POTENTIAL COMPLICATIONS, Continued

In the clinical setting, some of the above may additionally be attributable to user error in setting or adjusting the devices, to pacing lead displacement or breakage, and to faulty connections between pacing system components, ex. extension cables. CAUTION: When clinically indicated, supplemental monitoring of a patient should be considered during temporary pacing.

6

PROGRAMMABLE MODES AND PARAMETERS Single Chamber Modes AOO - Atrial Asynchronous Pacing Atrial pacing is provided at the programmed rate regardless of the intrinsic rhythm. AAI - Atrial Inhibited Pacing Atrial pacing at the programmed rate is provided in the absence of intrinsic activity. Intrinsic activity occurring in the alert period will reset timing to the beginning of the refractory period with inhibition of the output pulse. VOO - Ventricular Asynchronous Pacing Ventricular pacing is provided at the programmed rate regardless of intrinsic rhythm. VVI - Ventricular Inhibited Pacing Ventricular pacing at the programmed rate is provided in the absence of intrinsic activity. Intrinsic activity occurring in the alert period will reset timing to the beginning of the refractory period with inhibition of the output pulse. Dual Chamber Modes DOO - Dual Chamber Asynchronous Pacing Both chambers will be paced regardless of the underlying rhythm. DVI - AV Sequential Pacing The capability for pacing is available in both chambers with sensing only in the ventricle. In the absence of ventricular activity, both chambers will be paced at the programmed rate and AV delay. Ventricular activity occurring during the ventricular alert period and before the atrial output pulse will inhibit both output pulses and reset timing to the end of the AV delay. In the absence of ventricular activity during this period, an atrial output pulse will be provided at the end of the atrial escape interval and the timing for the AV delay will be initiated. Intrinsic ventricular activity during the AV delay will inhibit the ventricular output pulse and reset timing to the end of the AV delay. If intrinsic ventricular activity does not occur during the AV delay, a ventricular output pulse will be provided at the end of this interval, and a new atrial escape interval will be initiated. A ventricular blanking period occurs coincident with any atrial output pulse. This blanking period is intended to prevent detection of the atrial output pulse by the ventricular channel. DDI - Improved AV Sequential Pacing (With Intact Atrial Sensing) The capability for pacing and sensing is present in both chambers. However, sensed atrial activity will inhibit the atrial output pulse, but will not trigger a ventricular output pulse following the AV delay. DDI is a refinement of the DVI mode and will prevent competitive atrial pacing by maintaining atrial sensing. As with the DVI mode, AV sequential pacing at the programmed rate will be provided in the absence of intrinsic activity.

7

PROGRAMMABLE MODES AND PARAMETERS, Continued Additionally, intrinsic ventricular activity occurring during the atrial escape interval or AV delay will inhibit the output and reset the timing as previously described. However, unlike the DVI mode, intrinsic atrial activity during the atrial alert period will inhibit the atrial output pulse and prevent competitive atrial pacing. This sensing will not affect base rate timing and, in the absence of intrinsic ventricular activity, a ventricular output pulse will be provided at the basic rate. As with the DVI mode, a ventricular blanking period occurs coincident with any atrial output pulse. DDD - Dual Chamber Atrial Tracking - Pacing and Sensing In Both Chambers. In the absence of intrinsic activity, both chambers will be paced at the programmed rate. Intrinsic atrial activity during the atrial alert period will inhibit the atrial output pulse, terminate the atrial escape interval and begin the AV (PV) delay. Ventricular activity during the programmed AV delay will inhibit the ventricular output pulse, reset timing to the end of the AV delay and initiate a new atrial escape interval. The absence of atrial activity during the atrial alert period will result in an atrial output pulse at the end of the atrial escape interval and AV delay timing will begin. Intrinsic ventricular activity occurring during the ventricular alert period will always recycle both channels and inhibit both output pulses. It will also begin a new atrial escape interval. As with the DDI mode, a ventricular blanking period occurs coincident with any atrial output pulse. DDD Timing Scheme ↓ Atrial Escape Interval ↓ Ø | Atrial Channel Ø | | Ventricular Channel × ↑

Programmed Rate Interval ×Ø

Blanking Period Pacemaker Refractory

| | × ↑ Pacemaker Output AV Delay

↑↓

Pacemaker Alert

Limits of Intervals

Parameters Basic Pacing Rate The AccuPace may be programmed from 30 ppm to 180 ppm in increments of 1 ppm in both single-chamber and dual-chamber modes. The programming of rates is unimpeded from 30 ppm to 180 ppm. To accomplish this with high rates, automatic adjustments are made in the refractory period(s) and / or AV delay. Each is shortened in sequence as the rate is increased and restored as the rate is slowed. In DDD, at a programmed rate of 180 ppm and a tracking limit of 220 bpm, the maximum AV delay will be 87 milliseconds. Any setting higher than 87 milliseconds will slowly drop to this value as the programmed rate reaches 180 ppm. The pacing rate is independent of battery voltage, providing a constant pacing rate as the battery voltage gradually declines to and beyond the point at which the voltage drop triggers the low battery indicator, "L", on the status display.

8

PROGRAMMABLE MODES AND PARAMETERS, Continued NOTE: All Modes, when first turned On, start at 30 ppm. Rate can be changed, for all models, by using the Control Value, knob. If turned on by using the RESUME ON key the device will operate in the last operating condition.

Timing functions of an AccuPace are precisely determined by a crystal-controlled oscillator. As a consequence, there will be little difference between the rate of the AccuPace as programmed and displayed and that as determined by independent measurement of the pacing interval. An AccuPace is rate limited to 250 ppm in all modes except the Rapid Atrial Pacing Mode. For all models, the nominal rate for single-chamber modes is 70 ppm and dual-chamber modes is 60 ppm. These nominal values may be changed by the user following the instructions on page 18. Pulse Amplitude The pulse amplitude of the AccuPace pacing analyzer is programmable in steps of 0.1 volt from 0.1 to 10 volts. The standard value for output amplitude is 3.5 volts. This nominal value may be changed by the user following the instructions on page 18. The pulse amplitude is independent of battery voltage, providing a constant output as the battery voltage gradually declines to and beyond the point at which the voltage drop triggers the low battery indicator, "L", on the status display. Pulse Width Pulse width for the AccuPace analyzer is programmable from 0.05 millisecond to 1.0 millisecond in steps of 0.05 millisecond, and from 1.0 millisecond to 2.0 milliseconds in steps of 0.10 millisecond. The standard value is 0.40 millisecond. This nominal value may be changed by the user following the instructions on page 18. The pulse width is independent of battery voltage, providing a constant output as the battery voltage gradually declines to and beyond the point at which the voltage drop triggers the low battery indicator, "L", on the status display. Sensitivity Sensitivity may be programmed from a high of 0.5 millivolt on the atrial channel (1.0 millivolt on the ventricular channel) to 20 millivolts. From 0.5 to 10 millivolts, the value may be changed in steps of 0.5 millivolt. Above 10 millivolts, the step is 1.0 millivolt. The nominal value is 1.0 millivolt for the atrial channel and 3.5 millivolts for the ventricular channel. These nominal values may be changed by the user following the instructions on page 18. The sensitivity is independent of battery voltage, providing a constant sensitivity as the battery voltage gradually declines to and beyond the point at which the voltage drop triggers the low battery indicator, "L", on the status display.

9

PROGRAMMABLE MODES AND PARAMETERS, Continued AV Delay The AV delay defines the time interval between an atrial output pulse and a ventricular output pulse. The range of AV delays that is available makes it possible to significantly shorten the time between atrial and ventricular events, if it is hemodynamically or electrophysiologically advantageous in a particular instance. The time may also be lengthened to allow for inhibition of the ventricular output pulse in those individuals without significant AV conduction defect. The AV delay is programmable from 15 - 300 milliseconds in 1 millisecond steps. The standard value is 150 milliseconds. This nominal value may be changed by the user following the instructions on page 18. As previously stated, the AV delay will automatically shorten as the rate is raised toward its maximum value. The maximum value at a pacing rate of 180 ppm is 87 milliseconds.

10