Noninvasive recording of His-Purkinje activity in man by ORS-triggered signal averaging.

Abstract

Mobile instrumentation and a clinically applicable method have been developed for external His bundle recording. High gain signal amplification (10)(5) 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 electrodiogram 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 microV, 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 recording of His bundle activity with an analog delay device in normal subjects and patients with atrioventricular block

“…Subsequently, a noninvasive or virtually noninvasive method of recording His bundle activity was developed to overcome the limitations and complications involved in the use of the catheter technique as a routine examination [6]. The previous investigations on the noninvasive recording of His bundle activity were generally performed by the computer average response technique [7,8,[10][11][12][15][16][17][18], or by using exclusive averaging hardware [6,9,13,14,20]. For the averaging method to significantly improve the signal-to-noise ratio, the process of averaging must be driven by the trigger pulse with very accurate timing during the repeated processing.…”

“…A pretrigger recording method, in which a digital computer is employed, converts the analog signal to a digital signal that is stored in the digital memory. The P-QRS segment in the memory is then processed for averaging by QRS trigger pulse [12,13]. VandenAkker et al [11], however, introduced the post-trigger recording method.…”

Noninvasive recording of the His bundle electrogram in neonates

“…High-resolution, signal-processed electrocardiography has previously been shown to be practical in adults [4,7,11,13,17,20,23] for both the detection of His bundle potentials [7,11,13,17,20,23] and in some patients for the identification of ventricular late potentials [4,11,19] . Its use in infants has not been previously described .…”

The applicability of noninvasive his bundle electrogram to assessing the effect of digitalis on atrioventricular conduction

“…More recently, the feasibility of recording His-Purkinje electrograms from the body surface by signal averaging technique has been established (Berbari et af., , 1976Flowers and Horan, 1973;Flowers et al, 1974;Furness et af., 1975;Hishimoto and Sawayama, 1975;Hombach et al, 1982;; Mehra ef af., 1982; Nojima et af., 1985; Rozanski and Castellanos, 1980;Vincent et af. , 1978;Wajszczuk et al, 1978;Yanaga et al 1976). It may be possible using this noninvasive technique to disclose more accurate effects of digitalis on A-V conduction, since this technique could be applied repeatedly and for a longer time.…”