Investigating Calcium-Mediated Arrhythmias via a Computational Model of a Rabbit Atrial Myocyte

The system of transverse and longitudinal sarcolemmal tubules (T-system) is observed to remodel in atrial fibrillation (AF) and heart failure (HF). The resulting calcium dysregulation has been suggested to underlie disruptions in excitation-contraction coupling, and increase the frequency of arrhythmic events at the cellular scale; however, these mechanisms and their importance are yet to be fully described. A stochastic, 3D, spatiotemporal model of the rabbit atrial myocyte was developed in order to study calcium-mediated arrhythmic phenomena at the cellular scale. Preliminary findings suggest a relationship between the severity of detubulation, and the promotion of spontaneous activity, and provides insight into the conditions required for the emergence of spontaneous activity within atrial myocytes in HF.