In the information transmission mechanism of excitable cells such as neurons and cardiac cells, electrophysiological phenomena play an important role. To analyze the action potential propagation, many numerical simulations have been reported for modeling excitable cells and tissues into a complex of conductive and dielectric media. In this paper, the numerical simulation of action potential propagation in a two-dimensional model of anisotropic cardiac muscle is presented. We considered the three types of the transmembrane ionic current. Hodgkin-Huxley (HH) model, fast sodium current (FS) model and the Beeler-Reuter (BR) model. In the case of the BR model, intracellular calcium-ion density is also calculated, which is an important parameter for muscle contraction in cardiac tissue. For the two-dimensional model of cardiac tissue, we assumed that 1) muscle fibers are parallel to the
x-direction and the conductivity differs in
x- and
y-direction, 2) the tissue is so thin that intra- and extracellular currents are parallel to the membrane surface while transmembrane current is normal to it, and 3) the extracellular-to-intracellular conductivity ratio is constant in both
x and
y directions. As a result, the propagation velocities in the
x and
y directions,
vx and
vy respectively, are found to be
vx=43.9cm/sec and
vy=31.3cm/sec in HH model, while
vx=30.1cm/sec and
vy=20.8cm/sec in BR model, which are in good agreement with experimental data. Total computation times for FS and BR models are found to be, respectively, 2 and 109 times longer than that for the HH model.
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