Electrophysiological determinants of arrhythmic susceptibility upon endocardial and epicardial pacing in guinea-pig heart

Acta Physiologica
O E Osadchii

Abstract

Endocardial pacing instituted to treat symptomatic bradycardia may nevertheless promote tachyarrhythmia in some pacemaker-implanted patients. We sought to determine the contributing electrophysiological mechanisms. Left ventricular (LV) monophasic action potential duration (APD(90)) and effective refractory periods were determined in perfused guinea-pig hearts along with volume-conducted ECG recordings during epicardial and endocardial stimulations. Consistent with electrotonic modulation of repolarization, APD(90) at a given (either epicardial or endocardial) recording site tended to be longer while pacing from the ipsilateral LV site as compared to stimulations applied at the opposite side of ventricular wall. As a result, the intrinsic transmural repolarization gradient was amplified during endocardial pacing while being significantly reduced upon epicardial stimulations. The maximum slope of APD(90) restitution was greater upon endocardial than epicardial pacing. The excitability was found to recur at earlier repolarization time point at endocardium than epicardium, thereby contributing to increased endocardial critical intervals for re-excitation. Premature extrasystolic beats could have been elicited at shorter coupling s...Continue Reading

References

Dec 15, 1978·Pflügers Archiv : European journal of physiology·R Ochi, K Hashimoto
Nov 1, 1990·Circulation Research·R C Tan, R W Joyner
Apr 1, 1986·Journal of Molecular and Cellular Cardiology·M J JanseF Wilms-Schopman
Nov 1, 1986·Journal of Molecular and Cellular Cardiology·M Hiraoka, Y Hirano
Jan 1, 1980·Progress in Biophysics and Molecular Biology·M R Boyett, B R Jewell
Oct 10, 1997·The American Journal of Physiology·K R LauritaD S Rosenbaum
Jun 21, 2003·American Journal of Physiology. Heart and Circulatory Physiology·Stephen ZichaStanley Nattel
Jan 18, 2006·Journal of Molecular and Cellular Cardiology·Barbara RosatiDavid McKinnon
Jan 18, 2006·Journal of the American College of Cardiology·Michael O Sweeney, Frits W Prinzen
Jul 27, 2006·Acta Physiologica·A O VerkerkH L Tan
Nov 24, 2006·American Journal of Physiology. Heart and Circulatory Physiology·Ann M PitruzzelloSalim F Idriss
Feb 14, 2007·Pflügers Archiv : European journal of physiology·Ian N SabirChristopher L-H Huang
May 5, 2007·The Journal of Physiology·Nathalie GaboritSophie Demolombe
Sep 22, 2009·Pflügers Archiv : European journal of physiology·Ewa SoltysinskaThomas Jespersen
Jan 23, 2010·Circulation Research·Alexey V GlukhovIgor R Efimov
Oct 5, 2010·American Journal of Physiology. Heart and Circulatory Physiology·Rachel C MylesGodfrey L Smith
Dec 28, 2010·American Journal of Physiology. Heart and Circulatory Physiology·Oleg E OsadchiiSoren Peter Olesen

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