Elsevier

Journal of Electrocardiology

Volume 45, Issue 6, November–December 2012, Pages 663-669
Journal of Electrocardiology

Implanted cardiac pacemaker pulses as recorded from the body surface

https://doi.org/10.1016/j.jelectrocard.2012.08.008Get rights and content

Abstract

This study investigates the characteristics of contemporary pacemaker pulses as recorded from the body surface. Twelve-lead paced ECGs from 140 patients (68 ± 12 years, 71% males) were collected at 32,000 samples per second. Pacer pulses were manually annotated based on the high-sampling rate data stream. The results show that durations of the various pulses are stable, while amplitudes exhibit large variations. Also, more than 50% of pulses have either durations < 0.5 ms or amplitudes < 2 mV, which are the AAMI/IEC thresholds for detection and marking of pacemaker pulses on an ECG report. Therefore the current standards for pacemaker pulse detection are not fit for purpose and require to be updated. Further, this study suggests that a high-sampling rate database should be used as a standard test for pacemaker annotation and detection from body surface ECGs.

Introduction

There is an increasing trend for patients to be treated by implantation of cardiac pacemakers. The number of inpatients treated within the United States has increased from 170,000 in 2004 to 397,000 in 2009, based on two reports by the American Heart Association (AHA) in 20071 and 2012.2 Also, there were 68,000 implantable cardioverter-defibrillator (ICD) procedures carried out in 20041 and 116,000 in 2009.2 Furthermore, the 2012 AHA report stated that many more procedures were being performed on an outpatient basis.

In 1999, the first author managed a team at Burdick Inc. to handle customer issues. One of the biggest complaints from the field was faulty artificial pacemaker detection by an ECG device. A classical front-end data acquisition module of an ECG device contains an analog edge detector, and may also include software to measure spike durations and check for interference (Fig. 1A). The Burdick team put a lot of energy into improving this system, but the performance was still below expectations of high pacemaker pulse detection accuracy. The front-end module was developed and tested to meet the then current AAMI/IEC specifications[4], [5] that are taken from a 1991 version of AAMI EC-11 which was based on a single studied pacer case.4 To us, the key problem was that nobody had well-specified details of what a pacemaker pulse looked like at the body surface (how wide, how tall, etc.). Nobody knew how to develop and evaluate a pacemaker detection system to reliably meet clinical requirements. It was therefore very important to investigate the characteristics of contemporary pacemaker pulses from body surface ECGs in order to detect pacing pulses correctly. Moreover, the analog design approach has significant limits in relation to making prompt hardware improvements required on account of the constant advance of complex contemporary pacemaker functionality.

In 2003, the Burdick team developed an 8000-samples-per-second (8-ksps) digital pacer detection system (Fig. 1B). It had improved sensitivity, but its specificity was not high enough, especially for handling static electricity and other pacer-like interference. Its lower bandwidth (not greater than 1000 Hz) limits any improvement.

After years of research and study, in 2006, the Burdick team (at Cardiac Science Corporation) released a 12-lead ECG machine, the Atria 6100 (with FDA 510(k) clearance), with an innovative design.6 The analog detector or 8-ksps digital detector of earlier machines was replaced by a 64-ksps digital detection system, also in Burdick E8300 and E8500 devices (Fig. 1C). There are two functions built into this pacer module. A high-speed pacer detection algorithm identifies pacer pulses. Also, the data sampled at high-speed can be collected at a decimated rate of 32 ksps by dumping it to a separate medium for further analysis. One of the big advantages of this digital solution is that the algorithm can be updated in a straightforward way without changing the hardware. To the best of our knowledge, this was the first commercial ECG device with software-based pacer detection using digital data acquired at a very high-sampling rate in the US and international markets. This new technology can significantly improve the body surface pacemaker detection accuracy.[7], [8] Recently, this solution has become a standard form of design for a contemporary high-end ECG device and a similar high-sampling rate schema for pacer detection from the body surface is now employed by other ECG manufacturers (e.g., Reference9).

In brief, with newly developed high-sampling rate technology, it was feasible to visualize and analyze the characteristics of pacemaker pulses as recorded by an electrocardiograph, as shown in Fig. 2. In our previous study,10 measured amplitudes, durations, polarities, and intervals of pacemaker pulses as viewed from 12-lead ECGs collected by the high-sampling rate data acquisition system were reported. In this study, the results are updated on the basis of a larger database.

Section snippets

Equipment

By using Cardiac Science Atria 6100 units through the standard 12-lead ECG hookup, digital data were collected simultaneously from 8 independent leads (I, II, V1, V2, V3, V4, V5, and V6) at both 500 sps and 32 ksps. The data streams were dumped onto memory media and later transmitted to a PC system for this study.

Recording

All patients had an implanted pacemaker. Patients were invited to participate in the study either during routine follow-up appointments at outpatient clinics or when in hospital

Patient population

ECGs from 150 patients with implanted pacemakers were collected in two hospitals during three different periods. Ten records were excluded from this study due to technical and other issues. Therefore, 140-patients' ventricular-paced ECGs (mean age 68 ± 12 years, 71% males) were assessed.

Set 1 collected at Glasgow Royal Infirmary in 2007, included 37 patients (11 BiV and 26 RV pacing) with a mean age of 66 ± 11 years, of whom 73% were male.6

Set 2 obtained from the University Medical Center of Tucson

Sampling rate

Why 32 ksps? 32-ksps has a 31.25-μs interval between two adjacent sample points. If the duration of an implanted pacemaker is 0.5 ms at a typical clinical setting, there will be approximately 16-sample points to represent this 0.5 ms duration (Fig. 5). Then, there will be a sufficient number of sample points to plot the fast rising and falling edges of pacer pulses, so that pattern recognition techniques can be employed to differentiate pacer pulses from interference. As mentioned in the

Conclusions

Although durations of the various pacemaker pulses are stable, pulse amplitudes exhibit large variations. Over half of all pulses studied, atrial or ventricular, had an amplitude or duration below the detection thresholds that manufacturers can use to claim that their equipment meets current standards. These important results show that the current (2007) AAMI/IEC standards for pacemaker pulse detection are not fit for the purpose and require to be updated. Further, this study suggests that a

Acknowledgments

The authors wish to thank Drs. Jack Fairweather and Martin Jennings, together with Elaine Clark and Brian Devine at the University of Glasgow, as well as Kathy Gear, RN, and Dr. Frank Marcus at the University of Arizona for their help in collecting body surface ECGs from patients with implanted cardiac pacemakers at Glasgow Royal Infirmary, Scotland, and University Medical Center in Tucson, Arizona. The authors also thank Wei Hong, for his contribution to the study.

References (15)

  • S. Luo et al.

    A review of electrocardiogram filtering

    J Electrocardiol

    (2010)
  • S. Luo et al.

    Modern pacemaker stimuli as viewed from a 12-lead ECG

    J Electrocardiol

    (2009)
  • W. Rosamond et al.

    Heart Disease and Stroke Statistics 2007 update: a report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee

    Circulation

    (2007)
  • V.L. Roger et al.

    Heart Disease and Stroke Statistics 2012 update: a report from the American Heart Association

    Circulation

    (2012)
  • American National Standard ANSI/AAMI EC11

    Diagnostic electrocardiographic devices

    (2007)
  • International Standard IEC 60601-2-51. Medical electrical equipment—part 2–51: particular requirements for safety, including essential performance, of recording and analyzing single channel and multichannel electrocardiographs

    (2003)
  • J.A.A. Fairweather et al.

    Computer analysis of implanted cardiac pacemaker rhythm

    Comput Cardiol IEEE

    (2007)
There are more references available in the full text version of this article.

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