Temporal and Spatial Indices of AF Regularization Predict Intraprocedural AF Termination and Outcome.

Ablation has become a cornerstone of therapy for atrial fibrillation (AF), the most common arrhythmia in the Western world and an important cause of morbidity and mortality.1 However, the optimal approach for ablation remains hotly debated, and this is particularly true for the selection of procedural endpoints. Since seminal studies by Haïssaguerre et al.2 showed that ectopy from the pulmonary veins (PVs) may trigger paroxysms of AF, PV isolation has become central to most ablation approaches. However, PV isolation often fails to terminate AF, particularly in patients with persistent AF,3 indicating AF sustaining mechanisms that lie outside the PVs. For this reason or to eliminate additional triggers, many approaches to ablate extra-PV tissue have been devised whose AF termination rates range from 58% 4 to 87%.5 However, some constants remain. First, the event of AF termination is currently extremely difficult if not impossible to predict a priori. Second, AF termination by current ablative approaches is typically to atrial tachycardia, rather than to the sinus rhythm from which AF usually initiates. Finally, third, despite the intuitive advantages of AF termination, it remains disputed whether AF termination by current approaches is a desirable endpoint that improves long-term outcome. This brief review focuses on these facets of intra-procedural AF termination. Temporal and Spatial Indices of AF Regularization Predict Intraprocedural AF Termination and Outcome