Predicting unpinning success rates for a pinned spiral in an excitable medium

Today, the only robust technique for terminating ventricular fibrillation is an electrical shock of up to 400 joules. A reliable more gentle alternative to this procedure is desirable, as the strong currents of the shock may result in cardiac lesions and therefore may increase the risk of further abnormal heart rhythms. Reentrant arrhythmias are associated with the existence of spiral waves in the tissue. Their termination by local control is substantially limited by anchoring of these waves at natural heterogeneities. Far-field pacing (FFP) is a control strategy that has been shown to be capable of unpinning waves from obstacles. The success of unpinning is both frequency-dependent and sensitive to the initial position of the spiral. Therefore, in this article, we systematically analyze the response of a single pinned wave to FFP. By quantifying the response of the wave for a single pulse in a generic model of excitable media and incorporating the results into an iterative map, we predict the response of the wave to multiple pulses.