In a computational model of cardiac excitation, spatiotemporal complexity in atrial fibrillation is maintained by a dynamical balance between wave coalescence and wave collapse.
Computational modeling reveals that sustained atrial fibrillation is maintained by a balance of wave coalescence and collapse rather than continuous wave breakup.
While spiral wave breakup has been implicated in the emergence of atrial fibrillation, its role in maintaining this complex type of cardiac arrhythmia is less clear. We used the Karma model of cardiac excitation to investigate the dynamical mechanisms that sustain atrial fibrillation once it has been established. The results of our numerical study show that spatiotemporally chaotic dynamics in this regime can be described as a dynamical equilibrium between topologically distinct types of transitions that increase or decrease the number of wavelets, in general agreement with the multiple wavelets' hypothesis. Surprisingly, we found that the process of continuous excitation waves breaking up into discontinuous pieces plays no role whatsoever in maintaining spatiotemporal complexity. Instead, this complexity is maintained as a dynamical balance between wave coalescence-a unique, previously unidentified, topological process that increases the number of wavelets-and wave collapse-a different topological process that decreases their number.
Marcotte et al. (Fri,) conducted a other in Atrial fibrillation. Karma model of cardiac excitation was evaluated. In a computational model of cardiac excitation, spatiotemporal complexity in atrial fibrillation is maintained by a dynamical balance between wave coalescence and wave collapse.