Safety in purkinje to ventricular conduction and reentrant activity under simulated 1B ischemia

During the subacute phase of ischemia, electrophysiological alterations and cellular uncoupling set the stage for reentry. In the present work, we have developed a computational model of a fiber and a ring composed by Purkinje cells coupled to a ventricular fiber, which includes a 1B ischemic zone, a border zone and a normal zone. Simulations have been conducted to analyze the effects of cellular uncoupling and hyperkalemia on AP propagation. The results have shown that propagation block (safety factor SF < 1) occurred for low and high ventricular coupling (R_endo 5 Omegamiddotcm² and 40 Omegamiddotcm² respectively) as long as hyperkalemia was severe. Additionally, intermediate cellular coupling favored propagation. In the ring model, reentry was obtained for low values of R_endo. In conclusion, cellular uncoupling during 1B ischemia and hyperkalemia are crucial factors in the generation of propagation block, and reentry.