A computer model of propagated excitation and recovery in anisotropic cardiac tissue has been described in the first two reports of this series. The model consists of a large number of excitable elements whose subthreshold interactions are governed by the anisotropic bidomain theory but whose suprathreshold behavior (action potential) is largely preassigned. As described in the previous two reports, the model's performance was tested in rectangular and cubic arrays of excitable elements and in the "normal" three-dimensional simplified left ventricle with anisotropy. The present report deals with arrhythmogenic conditions in the simplified left ventricle with anisotropy and ventricular-gradient properties; specifically, we studied activation and recovery in the presence of an ischemic region and under various stimulation protocols. The aim of these simulations was to elucidate the role of reentry in the genesis of ventricular tachycardia. Our simulations produced reentrant activation as a result of appropriate endocardial stimulation.
Action Potentials Computer Simulation