Computer modelization of myocardial depolarization: application to fibrillation

A physiological application of a previously described computer simulation of the ventricular activation wave front is presented. The model of the depolarizing wave inside the ventricular wall is based on Huyghen´s construction method and has, in a first step, been developed to reproduce normal conduction conditions. The study reported simulates the effects of a severe ischemia, when cellular depolarization occurs, leading to progressive inactivation of sodium channels and resulting in conduction velocity decrease and dispersion of refractory periods. The model shows that reducing conduction velocity has an effect on myocardium contraction but does not seem sufficient to induce reentry. On the contrary, dispersion of refractory periods, even in a small range (17%), can induce percolation reentries, resulting in anarchic contractions and ventricular fibrillation