Modeling defibrillation: effects of fiber curvature.

The goal of this modeling study is to demonstrate extinguishing of a spiral wave reentry in a sheet of myocardium that incorporates curved fibers. The tissue is represented as a homogeneous bidomain with unequal anisotropy ratios. The spiral wave is initiated via cross-field stimulation of the bidomain sheet. The defibrillation shock is delivered via two line electrodes that occupy opposite tissue boundaries. Simulation results demonstrate that large-scale regions of depolarization are induced under the cathode as well as at locations in the vicinity of the anode. For high shock strengths, the new wavefronts generated from the regions of induced depolarization restrict the spiral wave pathway and render the tissue too refractory to further maintain the reentry. Weak shocks leave large portions of the sheet unaffected allowing the spiral wave to find recovered tissue and thus survive.