Complex-periodic cardiac spiral waves and their multi-stability in populations of rat ventricle cells

Dynamics and instabilities of reentrant spiral waves in excitable cardiac tissues are important in understanding various forms of cardiac arrhythmias such as ventricular tachycardia and fibrillations. However, they are still a subject far from being well understood. Here, we present complex-periodic cardiac spiral waves arising in a cultured monolayer tissue of rat ventricle cells. An interesting sequence of spontaneous transitions is observed. We demonstrate that this unusual phenomenon is driven by an intricate interplay between the spiral core and neighboring localized (absolute and partial) conduction blocks, to which the spiral core is entrained.