Effects of patchy dispersion of the coupling resistance and refractoriness on cardiac reentries

This study aimed at finding preponderant factors able to provoke cardiac reentries linked to ischemia. Numerical simulations of a sheet of ventricular wall were based on the van Capelle and Durrer model and performed on a 128/spl times/128 array. They showed that alteration of (1) action potential duration and (2) action potential duration and coupling resistance did not lead to pathological patterns with a cell by cell dispersion. In the contrary, when a patchy dispersion was envisaged, double-limb reentries could occur under peculiar conditions. To do so, a sufficient patch size was necessary (critical size) for both (1) and (2). Moreover, the probability of reentry was an increasing function of the number of ischemic patches. Some of these functionally reentrant patterns can be related to polymorphic tachycardia.