A Study of Atrioventricular Conduction in Man Using Premature Atrial Stimulation and His Bundle Recordings

Abstract

SUMMARYIn 20 subjects the effects of controlled premature atrial stimulation on atrioventricular conduction was studied using an electrode catheter technic for recording electrical activity of specialized conducting fibers. recording the electrical activity of the specialized conduction system.10' 1 Methods Right heart catheterization was performed on 20 subjects in the post-absorptive, nonsedated state. All subjects were in normal sinus rhythm at the time of study. Using local anesthesia, a tripolar electrode catheter* was percutaneously introduced into the right femoral vein and fluoroscopically positioned across the tricuspid valve. This catheter was used to record A-V nodal, His bundle, and right bundle-branch potentials as described in previous communications.10' 11 The proximal terminals of the electrode catheter were plugged into a multichannel distribution switch boxt which permitted the selection of any two electrodes for bipolar recordings, Each channel of the distribution switch box was led into the AC input of an ECG preamplifier. The filter frequencies of the ECG preamplifier were set at 40

Asynchrony of Conduction within the Canine Specialized Purkinje Fiber System

“…Conduction depression due to prematurity may be severe enough to induce complete (16) or localized block within the specialized conducting system below the AV junction. This localized block may be attributed to the fact that the premature impulse falls on a less negative take-off potential than in the fiber with the better propagated response.…”