Dynamics and cardiac arrhythmias.

Cardiac arrhythmias, characterized by single or multiple reentrant circuits, represent a dynamic phenomenon in an excitable medium. In this review, we provide a brief overview of how cardiac action potential duration restitution, conduction velocity restitution, and intracellular calcium cycling regulate the dynamics of action potential excitation and wave propagation in relation to the genesis and maintenance of cardiac arrhythmias.