HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/6/H2803    most recent 00299.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Qu, Z. Search for Related Content PubMed PubMed Citation Articles by Qu, Z.

Dynamical effects of diffusive cell coupling on cardiac excitation and propagation: a simulation study

Cardiovascular Research Laboratories, Department of Medicine (Cardiology), David Geffen School of Medicine at the University of California, Los Angeles, California 90095

Submitted 25 March 2004 ; accepted in final form 20 July 2004

Cell coupling is considered to be important for cardiac action potential propagation and arrhythmogenesis. We carried out computer simulations to investigate the effects of stimulation strength and cell-to-cell coupling on action potential duration (APD) restitution, APD alternans, and stability of reentry in models of isolated cell, one-dimensional cable, and two-dimensional tissue. Phase I formulation of the Luo and Rudy action potential model was used. We found that stronger stimulation resulted in a shallower APD restitution curve and onset of APD alternans at a faster pacing rate. Reducing diffusive coupling between cells prolonged APD. Weaker diffusive currents along the direction of propagation steepened APD restitution and caused APD alternans to occur at a slower pacing rate in tissue. Diffusive current due to curvature changed APD but had little effect on APD restitution slope and onset of instability. Heterogeneous cell coupling caused APD inhomogeneities in space. Reduction in coupling strength either uniformly or randomly had little effect on the rotation period and stability of a reentry, but random cell decoupling slowed the rotation period and, thus, stabilized the reentry, preventing it from breaking up into multiple waves. Therefore, in addition to its effects on action potential conduction velocity, diffusive cell coupling also affects APD in a rate-dependent manner, causes electrophysiological heterogeneities, and thus modulates the dynamics of cardiac excitation. These effects are brought about by the modulation of ionic current activation and inactivation.

electrical restitution; alternans; reentry; heterogeneity

This article has been cited by other articles:

				V. Jacquemet and C. S. Henriquez Loading effect of fibroblast-myocyte coupling on resting potential, impulse propagation, and repolarization: insights from a microstructure model Am J Physiol Heart Circ Physiol, May 1, 2008; 294(5): H2040 - H2052. [Abstract] [Full Text] [PDF]

				P. Colli Franzone, L. F. Pavarino, S. Scacchi, and B. Taccardi Monophasic action potentials generated by bidomain modeling as a tool for detecting cardiac repolarization times Am J Physiol Heart Circ Physiol, November 1, 2007; 293(5): H2771 - H2785. [Abstract] [Full Text] [PDF]

				Z. Qu, A. Garfinkel, and J. N. Weiss Vulnerable Window for Conduction Block in a One-Dimensional Cable of Cardiac Cells, 2: Multiple Extrasystoles Biophys. J., August 1, 2006; 91(3): 805 - 815. [Abstract] [Full Text] [PDF]