M-cell heterogeneity influence in arrhythmic pattern formation in sub-epicardial regional ischemia: A simulation study

Ventricular arrhythmias are often triggered by acute myocardial ischemia. The occurrence of lethal arrhythmias is normally related with myocardial injury, alterations of ionic conductances and metabolite concentrations. Ischemia alters the myocardium heterogeneously, differently affecting epicardium, M-cells and endocardium. In this computational study, we calculate the vulnerability to reentry during different stages of regional sub-epicardial ischemia in dissimilar island configurations of M cells in the myocardial wall (Antzelevitch's hypothesis). The main components of ischemia (hypoxia, acidosis and hyperkalemia) were considered in the model. The tissue comprises 150×300 cells, which include different islands of M cells up to 55% tissue area, 20% for epicardial cells and the rest of endocardial zone. The results of the model predict that the vulnerable window for re-entry has a logistic behaviour during sub-epicardial ischemia, with re-entry paths comprising midmyocardial islands of tissue.