The role of heterogeneities and intercellular coupling in wave propagation in cardiac tissue.
Electrical heterogeneities play a role in the initiation of cardiac arrhythmias. In certain pathological conditions such as ischaemia, current sinks can develop in the diseased cardiac tissue. In this study, we investigate the effects of changing the amount of heterogeneity and intercellular coupling on wavefront stability in a cardiac cell culture system and a mathematical model of excitable media. In both systems, we observe three types of behaviour: plane wave propagation without breakup, plane wave breakup into spiral waves and plane wave block. In the theoretical model, we observe a linear decrease in propagation velocity as the number of heterogeneities is increased, followed by a rapid, nonlinear decrease to zero. The linear decrease results from the heterogeneities acting independently on the wavefront. A general scaling argument that considers the degree of system heterogeneity and the properties of the excitable medium is used to derive a dimensionless parameter that describes the interaction of the wavefront with the heterogeneities.
Steinberg
Benjamin E
BE
Programme in Cell Biology, Hospital for Sick Children and Institute of Medical Science, University of Toronto, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
Glass
Leon
L
Shrier
Alvin
A
Bub
Gil
G
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D016880:Anisotropy; D002450:Cell Communication / Q000502:physiology*; D003198:Computer Simulation; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D008959:Models, Neurological; D032383:Myocytes, Cardiac / Q000502:physiology*