Conduction recovery after pulmonary vein isolation for atrial fibrillation

Background Although pulmonary vein (PV) isolation is useful for curing atrial fibrillation (AF), its recurrence rate is still high, so the aim of the present study was to investigate the cause of recurrence after PV isolation. Methods and Results Eighty-five patients with paroxysmal AF underwent PV isolation and AF recurred in 48 patients after the first session. Thirty of these 48 patients who underwent a second session were evaluated. In 49 (71%) of 69 PVs ablated in 25 patients (83%), recovery of conduction was observed between the left atrium and PV. In 45 (92%) of 49 PVs, conduction recurrences were seen from the same segment or part of a segment that was ablated in the first session. However, in the other 4 PVs (8%), conduction recurrences occurred in a different segment that had not been ablated before. In the second session, the mean number of segments ablated in the PV ostium was significantly less than in the first session (2.3 +/- 5.0 vs 1.4 +/- 6.0, p<0.01). After the second session, 16 patients (53%) did not show recurrence of AF. Conclusion The major cause of recurrence of PV isolation was recovery of PV conduction from the same segment that had been ablated in the PV ostium. Therefore, an additional session may be necessary to increase the success rate.