Response of atrial fibrillation to pulmonary vein antrum isolation is directly related to resumption and delay of pulmonary vein conduction

Background - The role of pulmonary vein ( PV) isolation in ablative treatment of atrial fibrillation ( AF) has been debated in conflicting reports. We sought to compare PV conduction in patients who had no AF recurrence ( group I), patients who could maintain sinus rhythm on antiarrhythmic medication ( group II), and patients who had recurrent AF despite antiarrhythmic medication ( group III) after PV antrum isolation ( PVAI). Methods and Results - PV conduction was examined in consecutive patients undergoing second PVAI for AF recurrence. We also recruited some patients cured of AF to undergo a repeat, limited electrophysiological study at > 3 months after PVAI. All patients underwent PVAI with an intracardiac echocardiography ( ICE) - guided approach with complete isolation of all 4 PV antra ( PVA). The number of PVs with recurrent conduction and the shortest atrial to PV ( A-PV) conduction delay was measured with the use of consistent Lasso positions defined by ICE. Late AF recurrence was defined as AF > 2 months after PVAI with the patient off medications. Patients in groups I ( n = 26), II ( n = 37), and III ( n = 44) did not differ at baseline ( 38% permanent AF; ejection fraction 53 +/- 6%). Recurrence of PV - left atrial ( LA) conduction was seen in 1.7 +/- 0.8 and 2.2 +/- 0.8 PVAs for groups II and III but only in 0.2 +/- 0.4 for group I ( P +/- 0.02). In patients with recurrent PV-LA conduction, the A-PV delay increased from the first to second procedure by 69 +/- 47% for group III, 267 +/- 110% for group II, and 473 +/- 71% for group I ( P < 0.001). When pacing was at a faster rate, A-PV block developed in all 5 of the group I patients with recurrent PV-LA conduction. Conclusions - The majority of patients with drug-free cure show no PV-LA conduction recurrence. Substantial A-PV delay is seen in patients able to maintain sinus rhythm on antiarrhythmic medication or cured of AF compared with patients who fail PVAI.