Steven Evans, Beth Israel Medical Center; Elizabeth Cherry and Harold Hastings, Hofstra University;
Isabelle Banville and Richard Gray, University of Alabama.

Scroll waves of electrical activity in mammalian cardiac tissue have become a major focus of research because of their
central role in arrhythmogenesis. We simulate the effects of two electromechanical-uncoupling drugs (DAM and CytoD) on
the dynamics of sprial waves in ventricles using an existing 3D rabbit ventricular anatomical structure along with an
ionic cell model based on experimentally measured mesoscopic electrophysiological properties of rabbit cells. As in
experiments, we found that the use of DAM resulted mostly in stable tachycardia (single scroll waves) with a period of
about 135 ms, while with CytoD more complex fibrillatory states were observed (multiple scroll waves). The difference in
behavior between these two drugs can be explained in terms of the interaction between the ventricular structure and the
electrical cell dynamics.