Dynamics and interaction of filaments in a computational model of re-entrant ventricular fibrillation

Ventricular fibrillation (VF) is a lethal cardiac arrhythmia. Re-entry, in which action potential wavefronts rotate around filaments, is believed to sustain VF. In this study we used a computational model of multiple wavelet fibrillation in the thin-walled right ventricle (10 mm thick) and the thicker walled left ventricle (16 mm thick) to investigate the effect of tissue thickness and initiation protocol on re-entry, and to examine whether filament dynamics and interaction in the model could explain why re-entry is both rarely observed and short-lived in experimental studies that map electrical activation on the heart surface. We found (i) that the density of filaments, the proportion of transmural filaments and the proportion of filaments visible on the model surface were all higher in the 10 mm simulation, (ii) that the initiation protocol influences the rate of filament breakdown but not the number of filaments present after 1 s, and (iii) that although many filaments are visible on the surface of the model, the majority are visible for less than one rotation. This study shows that tissue thickness, geometry and initiation protocol influence electrical activation during VF, and that the rapid motion and interaction of filaments result in transient appearance of surface re-entry.