Noninvasive Real-Time Recording of Cardiac Conduction System Activity. Instrumentation and Method Used in QRS-Triggered Averaging. W. Wajszczuk, T. Palko, M.J. Stopczyk, T. Bauld, M.S. Moskowitz, J. Przybylski, R.J. Zochowski, and M. Rubenfire. Non-invasive Cardiovascular Diagnosis – Current Concepts, Edited by Edward B. Dietrich, Chapter 35, pp. 337-359, Copyright 1978, University Park Press, Baltimore.

His Bundle

Other Publications:

Noninvasive recording of His-Purkinje activity in man by ORS-triggered signal averaging. Wajszczuk WJ,  Stopczyk MJ, Moskowitz MS, Zochowski RJ, Bauld T, Dabos PL, Rubenfire M. Circulation. 1978 Jul; 58(1):95-102.

(http://www.labmeeting.com/papers/author/wajszczuk-w )

Mobile instrumentation and a clinically applicable method have been developed for external His bundle recording. High gain signal amplification 10⁵ filtering (30--300 Hz) and averaging (128 or 256 consecutive cycles) are used. Acquisition of signals arising in the P-R interval is triggered by the patient's QRS signal at the end of that interval. The precordial bipolar electrocardiogram is digitized at 5k HZ with 8 bit resolution and transferred to a 1,024 word, 18 bit signal averager. The averaged signal is then displayed on an oscilloscope and photographed. Good correlations were obtained between direct intracardiac and precordial recordings in experimental animals and in humans. Noise level after averaging was below 0.3 μV and there was good elimination of asynchronous atrial and ectopic ventricular activity. With averaging of 128 or 256 consecutive cycles, the signal attenuation after propagation to the chest wall was in the range 1:2000 to 1:4000 in comparison with the directly recorded His bundle activity deflections. The noninvasive method may be of value in follow-up of acute and chronic disturbances of atrioventricular conduction, as well as in studies of effects of pharmacologic interventions.

Noninvasive external recording of cardiac conduction system (His bundle) activity. Wajszczuk WJ, Moskowitz MS, Bauld T, Dabos P, Weiss R, Rubenfire M. Med Instrum. 1978, Sep-Oct;12(5):282-7.

http://www.labmeeting.com/papers/author/wajszczuk-w

Successful and adequate external recording of the cardiac conduction system from the body's surface can be accomplished in 80 to 90 percent of subjects studied. High-gain amplification, signal averaging, and triggering with a conditioned QRS signal results in good recording reproducibility. Averaging of 128 consecutive cycles is adequate, but on occasion averaging of 256 cycles may yield better results. The patients's QRS signal triggers the transfer of signals, which are digitized and stored during the preceding P-R interval. Comparison of external recordings with direct invasive recordings in animals and patients shows good correlation between the major His bundle deflections. The advantages of the system developed include its mobility, triggering the QRS with pre-trigger data processing, and instantaneous display on Polaroid photograph. Future research should concentrate on further miniaturization and simplification of the instrumentation, detailed experimental comparison between direct and external recordings for identification of deflections and their origin, further study of the recording lead system, and the most appropriate method of information display.

Pre-P (Sinus Node Region)

Sinus node activity in man and animal studies recorded intraatrially by an on-line pre-memorized averaging technique. Mariusz J. Stopczyk, Marian Pieniak, Waldemar J. Wajszczuk and Melvyn Rubenfire. Excerpta Medica International Congress Series No. 395. CARDIAC PACING, Proceedings of the Vth International Symposium, Tokyo, March 14-18, 1976, pp. 13-18. Excerpta Medica, Amsterdam, ISBN 90 219 0326 1.

Summary

A method for precordial His bundle potential recordings recently developed in our labora­tory was adapted for the visualization of sinoatrial (SA) node activity. The method includes high-gain amplification, filtering and averaging of the pre-memorized post-triggered signal. Potentials for averaging were recorded with a unipolar intraatrial lead with distant elec­trode located in a large venous vessel. A bipolar intraatrial recording (A wave deflection) was used as a trigger. Final recordings were obtained from averaging of up to 1,024 sinus beats and photographed from the oscilloscope.

The SA (pre-P) potential recordings obtained simultaneously in dog experiments (5 dogs) from the epicardial electrodes sutured in the area of the SA node and from the averaged unipolar intraatrial recording showed excellent correlation.

Pre-memorized averaged intraatrial recordings were obtained in humans (5 patients) during right heart catheterization using a multipolar electrode catheter. The recordings in both experi­mental animals and humans revealed double spiked, preatrial potentials of 40-50 μV and 1.0-1.5 μV amplitude, respectively, usually located 30-60 msec before the right atrial spike (or beginning of atrial activity). These potentials are assumed to represent the activity of the SA node. Electrophysiological as well as clinical applications of this method for recording of SA node activity require further study, but appear promising in evaluation of sinoatrial node function abnormalities.

Other publications:

Pre-P (Sino-Atrial Node Region) Activity Recording from the Right Atrial Cavity by Signal Averaging*. MARIUSZ J. STOPCZYK, WALDEMAR J. WAJSZCZUK, RYSZARD J. ZOCHOWSKI, MELVYN RUBENFIRE.  Pacing Clin Electrophysiol. 1979 Mar;2 (2):156-61.

*Presented in part at the Vth International Symposium on Cardiac Pacing. Tokyo, Japan. March 14–18, 1976. Copyright 1979 Official journal of the International Cardiac Pacing and Electrophysiology Society

 (http://www.labmeeting.com/papers/author/wajszczuk-w)

http://www3.interscience.wiley.com/journal/120057221/abstract?CRETRY=1&SRETRY=0

 http://onlinelibrary.wiley.com/doi/10.1111/j.1540-8159.1979.tb05195.x/abstract

A mobile instrumentation and noninvasive method developed recently for external His bundle recording and employing the signal averaging technique was applied for intra-atrial recording of the pre-P (sino-atrial node region) activity. Recordings were obtained in ten anesthetized dogs and five patients at the time of right heart catheterization. A bipolar intra-atrial lead was used for triggering of the averaging process and a unipolar intra-atrial lead was used for signal recording. Direct bipolar epicardial recordings were obtained for comparison from the sino-atrial (S-A) node area in experimental animals. In animals studies, the averaged intra-atrial recording showed 30 μV amplitude deflections beginning 40-45 ms prior to the onset of P wave and were preceded by a slow rise and lower frequency and amplitude deflections arising 60-70 ms earlier. There was good correlation between the pre-P activity recorded intra-atrially and from the epicardium. Deflections of similar configuration but smaller amplitude (1 μV) were recorded in human studies. They preceded the onset of large atrial activity deflections (P wave) in the reference electrocardiogram by 40-80 ms. The exact source of these pre-P activity potentials has not been definitely established, but they appear to originate from the S-A node region, based on their similarity to the direct epicardial recordings and time relationship to the preceding T and following P wave.

Experimental Correlations

Summary

The purpose of this communication is to review the experimental models and techniques, which have been utilized in our laboratory to identify the individual deflections in external (pre-triggered and signal averaged) recordings from the cardiac conduction system.

1. Electrode catheter recordings from the right ventricular cavity – 5 dogs. (Figure 1).

A multi-electrode catheter was introduced through a small incision in the right atrial appendage and advanced to the apex of the right ventricle. The catheter was gradually withdrawn towards the tricuspid valve. The signals from the distal pair of electrodes (10 mm apart) were observed on the oscilloscope. Bipolar recordings were obtained when His bundle deflections were noted and the position of the electrodes was verified by external palpation. Direct recordings were correlated with the external averaged recordings obtained prior to thoracotomy and after temporary closure of the chest after completion of the direct recording.

2. Endocardial recordings with multi-electrode patch – 10 dogs. (Figure 2).

A multi-electrode patch (15 x 30 mm) with 12 silver electrodes (0.5 mm in diameter) mounted in dacron mesh in three rows of four electrodes (4 – 5 mm apart) was used. Implantation of the electrode patch required temporary cardiopulmonary bypass. The electrode wires were brought outside the chest, which was then closed with loose sutures. The dogs were observed for 30-45 minutes to allow stabilization. Bipolar leads from various combinations of electrodes were examined on the oscilloscope and recordings were obtained from the pairs of electrodes, which displayed the cardiac conduction system potentials. They were then correlated with the external recordings.

3. Epicardial recordings from the S-A node region – 5 dogs. (Figure 3).

A multi-electrode patch (described above) was sutured in the area of the S-A node over the posterior aspect of the right atrium. Bipolar leads were examined in various combinations for the presence of earliest activity preceding the atrial activity in the reference leads and recordings were obtained from the pairs of electrodes showing this early activity. The appearance of these early deflections coincided with the position of the electrodes in the anatomic area suspected to contain the S-A node. Similar early activity deflections were seen in all experimental animals. (Figure 3A).

4. Intra-atrial recordings from the S-A node region – 10 dogs. (Figure 3).

A multipolar electrode catheter was advanced in anesthetized dogs via the femoral vein to the right atrium and positioned under gentle palpation along the junction of the superior vena cava and the right atrium. The catheter tip containing the terminal pair of electrodes was located in the vicinity of the presumed site of the S-A node. A unipolar lead from one of the electrodes of the pair was used for signal recording and a bipolar lead from the same pair of electrodes was used for triggering.

For comparison, direct bipolar epicardial recordings were obtained from the region of the S-A node utilizing the electrode patch (described above) or electrode strips containing silver electrodes with an interelectrode distance of 2-3 mm. The early low voltage deflections of averaged intra-atrial recordings corresponded closely to the earliest activity deflections recorded with the epicardial electrodes. It is assumed that both these deflections represent activation originating from the region of the S-A node. 

Examples of the recordings are shown below:

Publications listed below summarize our investigative work on this subject and are reproduced in their entirety:


1/ Non-invasive studies of cardiac conduction system. W.J.Wajszczuk, M.S. Moskowitz, T. Bauld, T. Palko, J. Przybylski, P. Dabos, R. Weiss, M. Stopczyk, R. Żochowski, M. Rubenfire. Proceedings of “BIOSIGMA 78”, International Conference on Signals and Images in Medicine and Biology, Paris, April 24-28, 1978. Session C.IV: Non-aggressive methods for data acquisition, Communication C.IV.2 - see


2/ NEW DEVELOPMENTS AND EXPERIMENTAL OBSERVATIONS ON EXTERNAL (NON-INVASIVE) RECORDING FROM THE CARDIAC CONDUCTION SYSTEM * W.J. WAJSZCZUK, J. PRZYBYLSKI, T. PAŁKO, M. WORPELL, TH. BAULD AND M. RUBENFIRE. Electrocardiology '81, Budapest, Hungary, 1981. Z. Antaloczy, and I. Preda (eds.)., pp. 89-94. - see

Presentations

PAPERS SUMMARIZED OR REPRODUCED ABOVE WERE PRESENTED AT THE NATIONAL AND INTERNATIONAL MEETINGS HELD IN:


1. TOKYO, JAPAN – 1976. Vth International Symposium on Cardiac Pacing, March 14–18, 1976.

2. SAN FRANCISCO, CA – 1977. AAMI, 12TH Annual Meeting, March 13-17, 1977.

3. PARIS, FRANCE – 1978. “BIOSIGMA 78” – International Conference on Signals and Images in Cardiology, April 24-28, 1978.

4. GLASGOW, SCOTLAND – 1978. 5th International Congress on Electrocardiology, September 5-8, 1978.

5. COLOGNE, GERMANY – 1981. International Symposium on the Signal Averaging Technique in Clinical Cardiology, May 7-9, 1981.

6. BUDAPEST, HUNGARY – 1981. 8TH International Congress on Electrocardiology, September 1-4, 1981.

At this point the research project was terminated because of the exhaustion of funds and inability to obtain further financial support!

Suggestions (and plans) for further continuation of research on this topic:

1/ further development of a method for three-dimentional (vectorial) representation of the activation of the cardiac physiological pacemaker and conduction system;
2/ experimental re-creation and study of various forms of the conduction system abnormalities;
3/ collection of clinical material representing various conduction abnormalities and development of the diagnostic criteria;
4/ can the A-V node activation potentials be identified (separated) in the external recordings?

His bundle cardiography - US Patent 4261369

US Patent Issued on April 14, 1981
Estimated Patent Expiration Date: February 14, 1999
http://www.patentstorm.us/patents/4261369/fulltext.html

Abstract
A non-invasive technique for monitoring the atrioventricular His bundle electrocardiogram and recording the same on a strip chart recorder in parallel real time with a conventional surface ECG signal. The preferred embodiment of the His bundle circuitry includes separately adjustable highpass and lowpass filters in the frequency range of 30 to 600 Hz, and a variable gain amplifier for in situ empirical adjustment to patient and environmental conditions.