Computer simulation of cardiac arrhythmias by incorporating phase response curve to a three-dimensional heart model

Cardiac arrhythmias were simulated using a three-dimensional heart model. Elements of a 3-D model were classified into limited types and each type was assigned with a set of electrophysiologic parameters. During simulation, the property for an individual element was determined according to its type, its location in the model, and its coupling interval of activation. In this way, cell dynamics were incorporated in the model. In addition to a sinus pacemaker, a parasystolic focus was set at the left ventricle of the model. The intrinsic cycle length of the ectopic focus was modulated by electrotonic effects of surrounding stimuli using a predefined phase response curve. The excitation process of the model and resultant torso electrocardiograms were computed. Clinically comparable results were obtained including bigeminy, trigeminy, quadrigeminy, and other types. This study demonstrated the usefulness of the three-dimensional model in investigating the mechanism of cardiac arrhythmias