Achievement of successful pulmonary vein isolation: methods of adenosine testing and incremental benefit of exit block

Purpose Several approaches were tried to achieve complete pulmonary vein isolation (PVI). The aims of this study were to (1) compare adenosine-induced PV conduction and exit conduction, (2) determine the adequate adenosine dose, and (3) investigate the correlation of dormant conduction and recurrence of atrial fibrillation (AF). Methods A total of 378 consecutive patients who underwent PVI from June 2012 to April 2015 were prospectively included (the de novo procedure in 318 (84.1 %) and a redo procedure in 60 (15.9 %)). After the exit block was assessed, 20 mg adenosine was injected into the left atrium. If dormant conduction was observed, 12 and 6 mg of adenosine were injected sequentially. Results Exit conduction during PV pacing was observed in 34 patients (9 %), and dormant conduction was observed in 92 patients (24.3 %). Among them, 74 (80.4 %, 74/92) demonstrated dormant conduction without exit conduction and 16 (47.1 %, 16/34) showed exit conduction without dormant conduction. The 20-mg dose of adenosine had an additive yield in patients with dormant conduction, compared to that of 12 mg (93 %, 86/92) or 6 mg (80 %, 74/92). There was no significant difference in the recurrence rate regarding dormant conduction. The pattern of prevalence of reconnected origin during the redo procedure was similar to that of dormant conduction during the index procedure. Conclusions There was a discrepancy between adenosine-induced PVI and exit block. Therefore, exit block test has additional value to verify latent incomplete PVI in conjunction with adenosine test. Furthermore, high-dose adenosine had an additive yield.