Clinical significance of induced atrial tachycardia after termination of longstanding persistent atrial fibrillation using a stepwise approach

Induced Atrial Tachyarrhythmia During Atrial Fibrillation Ablation. Introduction: The utility of inducibility test of atrial tachycardia (AT) in patients with longstanding persistent atrial fibrillation (AF; LPAF) is unclear. This study aimed to evaluate the significance of induced AT and the impact of their ablation on the clinical outcome. Methods: In 194 patients with LPAF (>1 year) who underwent catheter ablation (pulmonary vein isolation with substrate ablation), an inducibility test was performed after AF termination. Results: AT was induced in 108 (56%) patients (induced AT group); neither AT nor AF was inducible in 37 (19%, noninduction group). During 39 ± 21 months, AT recurred in 30 patients (28%), AF in 19 (17%), and no arrhythmia in 56 (52%) among induced AT group, although there was a recurrence of AT in 9 (24%, P = 0.68), AF in 6 (16%, P = 0.85), and no arrhythmia in 22 (60%, P = 0.42) among noninduction group (P = NS). Note that 10 patients with repeated ablation in induced AT group revealed 8 different and 2 similar recurrent ATs compared to the induced ATs at first session. The mean cycle length of induced AT that terminated by ablation (271 ± 64 ms) was longer than that without (249 ± 58 ms, P < 0.05). In induced AT group, AT recurrence rate in patients who achieved AT termination by ablation was lower than those without termination (5% vs 36%, P < 0.05). Conclusions: ATs that are inducible after LPAF termination do not necessarily become clinical AT. However, patients who achieved noninducibility of AT by ablating slower cycle length of AT had better outcomes. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1171-1178, November 2012)