Supernormal Excitability Causes Alternans, Block, Wavebreak and Reentry in Cardiac Tissue
نویسندگان
چکیده
منابع مشابه
Supernormal conduction in cardiac tissue promotes concordant alternans and action potential bunching.
Supernormal conduction (SNC) in excitable cardiac tissue refers to an increase of pulse (or action potential) velocity with decreasing distance to the preceding pulse. Here we employ a simple ionic model to study the effect of SNC on the propagation of action potentials (APs) and the phenomenology of alternans in excitable cardiac tissue. We use bifurcation analysis and simulations to study att...
متن کاملMechanisms of discordant alternans and induction of reentry in simulated cardiac tissue.
BACKGROUND T-wave alternans, which is associated with the genesis of cardiac fibrillation, has recently been related to discordant action potential duration (APD) alternans. However, the cellular electrophysiological mechanisms responsible for discordant alternans are poorly understood. METHODS AND RESULTS We simulated a 2D sheet of cardiac tissue using phase 1 of the Luo-Rudy cardiac action ...
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A computer model of a ring-shaped, one-dimensional cardiac fiber was used for examination of responses of propagation to premature stimuli applied under different degrees of both cell-to-cell coupling and membrane excitability. Results demonstrated the importance of cellular uncoupling in the genesis of unidirectional block and reentry. Propagation of excitation itself created a certain degree ...
متن کاملSupernormal Conduction and Suppression of Spatially Discordant Alternans of Cardiac Action Potentials
Spatially discordant alternans (DA) of action potential durations (APD) is thought to be more pro-arrhythmic than concordant alternans. Super normal conduction (SNC) has been reported to suppress formation of DA. An increase in conduction velocity (CV) as activation rate increases, i.e., a negative CV restitution, is widely considered as hallmark of SNC. Our aim in this study is to show that it...
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In this paper we use a simplified model of cardiac excitation-contraction coupling to study the effect of tissue deformation on the dynamics of alternans, i.e., alternations in the duration of the cardiac action potential, that occur at fast pacing rates and are known to be proarrhythmic. We show that small stretch-activated currents can produce large effects and cause a transition from in-phas...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2011
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2010.12.2565