Blocking the Pulmonary Vein to Left Atrium Conduction in Addition to the Entrance Block Enhances Clinical Efficacy in Atrial Fibrillation Ablation

Background: The unidirectional pulmonary vein (PV) to left atrium (LA) conduction after achieving PV entrance block has not been evaluated. Methods: Circumferential PV isolation was performed in 573 consecutive patients with atrial fibrillation (AF). The unidirectional PV to LA conduction and its influence on clinical outcomes were evaluated. Results: A total of 341 ipsilateral PVs (29.7%) with spontaneous activities (SAs) were documented in 231 patients (40.3%). The unidirectional PV to LA conduction was confirmed in 11 ipsilateral PVs (3.2%) of 11 patients (4.8%). Patients were classified to three groups: Group A (had unidirectional PV to LA conduction during SAs), Group B (with SAs but without PV to LA conduction), and Group C (without SAs). During a 30-minute observation, the reconnection incidence was higher in Group A (45.4%) than in Group B (13.9%, P = 0.042) and Group C (11.5%, P = 0.018). The reconnection time was shorter in Group A (10.8 +/- 9.8 minutes) than that in Group B (20.7 +/- 8.0 minutes, P = 0.037) and Group C (21.2 +/- 8.2 minutes, P = 0.022). All 11 PVs were successfully isolated and bidirectional block was achieved. Conclusion: Unidirectional entrance block with SAs in PVs may not be a good indication of complete PV isolation. Bidirectional block of the PV-LA junction can reduce the acute PV reconnection and may reduce the chronic AF recurrence in patients undergoing circumferential PV isolation.(PACE 2012; 18)