Higuchi S, et al. - In this retrospective analysis of 113 patients who had circumferential pulmonary vein isolation (CPVI) without an empirical substrate modification of persistent atrial fibrillation (PerAF), researchers determined the prognostic value of prolonged interatrial conduction time (IACT) for predicting AF recurrences following CPVI of PerAF They define IACT as the interval from the earliest P-wave onset on the ECG to the latest activation in the coronary sinus. They measured IACT after achieving the CPVI and conversion to sinus rhythm. They concluded that, for the prediction of AF recurrences after both initial and multiple CPVI procedures for PerAF, a prolonged IACT of ≥ 123 ms may have utility as a marker.