Cardioversion of persistent atrial fibrillation is associated with a 24‐hour relapse gap: Observations from prolonged postcardioversion rhythm monitoring

Background Many recurrences occur after electrical cardioversion (ECV) of atrial fibrillation (AF). Assessment of extent of remodeling and continuous prolonged rhythm monitoring might reveal actionable recurrence mechanisms. Hypothesis After ECV of AF specific patterns of arrhythmia recurrence can be distinguished. Methods All patients who underwent successful ECV due to persistent AF were included. Tissue velocity echocardiography during AF was performed before ECV to study atrial fibrillatory cycle length and fibrillatory velocity. After ECV, the heart rhythm of all patients was monitored 3 times daily during 4 weeks, and timing of recurrence was noted. Results In total, 50 patients (68% male) were included; mean age was 68 ± 9 years. Median duration of the current AF episode was 102 (range, 74–152) days. Twenty‐one (42%) patients showed recurrence of persistent AF. No recurrences occurred during the first 24 hours. There were no differences in clinical characteristics between patients with or without recurrence of AF. However, patients with early recurrence of AF had significantly higher precardioversion wall‐motion velocity compared with patients who remained in sinus rhythm (2.8 [1.6–3.6] vs 1.4 [0.9–3.3] cm/s; P = 0.017), whereas atrial fibrillatory cycle length did not differ. Conclusions In this study on 50 patients successfully cardioverted for persistent AF, there was a relapse gap of ≥24 hours. This phenomenon has not been well appreciated before and offers an AF‐free window of opportunity for electrocardiographically triggered cardiac imaging or complex electrophysiological procedures. Echocardiographic tissue velocity imaging may visualize atrial remodeling relevant to AF recurrence.