Late re-conduction sites in the second session after pulmonary vein isolation using adenosine provocation for atrial fibrillation

Intravenous adenosine triphosphate (ATP) administration could reveal dormant conduction (DC) gaps on the ablation line of a pulmonary vein isolation (PVI). We compared the ATP-provoked DC sites in the initial PVI with the PV re-conduction sites in the second session in patients with paroxysmal atrial fibrillation (AF). We conducted a multicenter, observational study from a prospective registry undergoing AF ablation. A total of 110 consecutive drug-refractory paroxysmal AF patients were enroled in this study. Dormant conduction was detected by an ATP provocation of up to 40 mg during a continuous isoproterenol infusion (0.52 g/min). The DC sites at each of the right and left PVs were precisely determined by using double spiral catheters under the guidance of a three-dimensional constructed anatomical mapping system. In the initial session, DC was observed in 35 patients (31.8, 1.3 gaps/patient), and the sites of the DC were commonly observed in the carina region (43.5). Atrial fibrillation recurrence was confirmed in 33 patients (30.0) during follow-up (27.1 months), and a second session was performed in 24 of 33 patients (70.6). In the second session, the re-conduction sites were also commonly observed in the carina region (59.5). The carina region was still a dominant re-conduction site even after the elimination of any ATP-provoked DC in the index procedure.