May 1, 1991

Effects of atrial impulse timing on AV concealed conduction in the rabbit heart

Pacing and Clinical Electrophysiology : PACE
F J ChorroV Valentin


The influence of the timing of a nontransmitted or transmitted atrial impulse on the atrioventricular (AV) conduction time of the subsequent impulse was studied in nine isolated rabbit hearts. AV conduction curves were determined by applying the atrial extrastimulus test. The extrastimulus was delivered preceded or not by an interposed atrial impulse whose coupling interval with respect to the last atrial beat of a basic train was kept constant at 100, 120, 140, 160, 175, 200, 225, 250, and 300 msec. In all experiments, there was a "concealment interval," i.e., the AV effective refractory period was longer than the atrial functional refractory period, and in seven experiments was comprised between 100 and 160 msec. For any given extrastimulus coupling interval in the presence of an interposed nontransmitted atrial impulse, AV conduction time was significantly greater than in its absence; the increase was greater than the longer the nontransmitted atrial impulse coupling interval, i.e., the shorter the subsequent transmitted impulse coupling interval with respect to the previous interposed nontransmitted impulse. The AV conduction curves relating the extrastimulus AV conduction time to its coupling interval with respect to the l...Continue Reading

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Mentioned in this Paper

Log-Linear Models
Refractory Period, Electrophysiological
Refractory Period
Atrial Function
Structure of Atrioventricular Node
Ventricular Function
Heart Atrium
Cardiac Pacing, Artificial
Cardiac Conduction
Cell Transformation

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