Competitive interactions between ectopic foci and reentry in virtual human atrium

Atrial arrhythmias (flutter and fibrillation) are characterised by rapid and irregular activation of atrium. There are two possible mechanisms: abnormal spontaneous electrical activity of ectopic foci and multiple reentrant wavelets. In this study, we developed a biophysically detailed computer model of virtual human atrium to study the interaction between the two major arrhythmic origins. Depending on their frequencies, phases and distance, the interaction is competitive with either ectopic focus or reentry dominating atrial electrical excitation. Collisions between the two lead to further wave-breaks and the formation of multiple reentrant wavelets, providing a source for persistent atrial fibrillation. Focal activity acting as an organising centre, or mother motor which drives and controls the rhythm of reentry was observed