Modeling induction of reentry with a realistic S2 stimulus

Reentry in cardiac tissue has been attained experimentally in a canine model using cross-field extracellular stimulation (D.W. Frazier et al., 1989). However, the mechanisms by which large areas of activation away from the shock electrode occur and initiate reentry remain unclear. This computational study attempts to explain such activation by realistically modeling an extracellular shock and incorporating the contributions of local areas of hyperpolarization and depolarization (“sawtooth potential”) that arise in cardiac tissue under an electric field due to the discrete nature of cardiac cells. A model incorporating local polarizations was found to result in reentry initiation in agreement with experimental results