DYNAMICS OF SCROLL WAVES IN INHOMOGENEOUS EXCITABLE MEDIA

Nonlinear waves in excitable media often organize themselves into vortex-like patterns of activity, called 'scroll waves' in three dimensions. In this paper we review recent results concerning the effects of inhomogeneities on scroll wave dynamics. We concentrate on the dynamics of scroll waves with initially rectilinear filaments evolving in the presence of linear parameter gradients with different orientations relative to the filament. We describe how this evolution is affected by the presence of localized defects. The effects described here are important in the study of cardiac arrhythmias, and may lead to an understanding of the mechanism of termination and stabilization of these arrhythmias.