Controlling Spiral Turbulence in Simulated Cardiac Tissue by Low-Amplitude Traveling Wave Stimulation

Abstract

Ventricular fibrillation (VF), a class of cardiac arrhythmias that is often fatal, is associated with the breakdown of spatially coherent activity in heart tissue. Modeling studies have linked VF with the onset of spatiotemporal chaos in the electrophysiological activity of the heart, through the creation and subsequent breakup of spiral waves. Conventionally, defibrillation is carried out by applying large electrical shocks to the heart which has harmful effects both in the short and long terms. Using nonlinear dynamics techniques, several low-amplitude control methods for VF have been suggested. However, all of them suffer from the problem of either having to use high power (applied over the entire system) or extremely high frequencies (which are unstable and may spontaneously give rise to further VF episodes). In this paper we propose a spatially extended but non-global scheme for controlling VF in simulated cardiac tissue. The method involves successive activation of electrodes arranged in a square array, such that, a wave of control stimulation is seen to propagate through the system. Our simulations involving both simple and realistic models of ventricular tissue show that spatiotemporal chaotic activity associated with VF can be terminated using low amplitude control.