Recurrence of arrhythmia following short-term oral AMIOdarone after CATheter ablation for atrial fibrillation: a double-blind, randomized, placebo-controlled study (AMIO-CAT trial).

AIMS Patients undergoing catheter ablation for atrial fibrillation (AF) often experience recurrent arrhythmias within the first few months post-ablation. We aimed to investigate whether short-term use of amiodarone to prevent early arrhythmias following radiofrequency ablation for AF could reduce later recurrence. METHODS AND RESULTS In a two-centre, randomized, double-blind, placebo-controlled study, we randomized a total of 212 patients undergoing AF ablation. Patients were stratified according to type of AF (paroxysmal/persistent) and history of previous AF ablation and randomly assigned to 8 weeks of oral amiodarone therapy or matched placebo following catheter ablation. Patients were followed for 6 months. Analyses were performed according to the intention-to-treat principle. Of 212 enrolled patients [median age 61 (inter-quartile range 54-66), 83% male, 50% paroxysmal, 29% with history of previous ablation], 206 patients were available for analysis of the primary end-point which was any documented atrial tachyarrhythmia lasting >30 s following a blanking period of 3 months. This was observed in 42/107 (39%) in the amiodarone group vs. 48/99 (48%) in the placebo group (P = 0.18). Among the secondary end-points, the amiodarone group showed significantly lower rate of atrial tachyarrhythmia-related hospitalizations [rate ratio = 0.43; 95% confidence interval (CI) = 0.23-0.77, P = 0.006] and cardioversions (rate ratio = 0.36; 95% CI = 0.20-0.62, P = 0.0004) within the blanking period. CONCLUSION Short-term oral amiodarone treatment following ablation for paroxysmal or persistent AF did not significantly reduce recurrence of atrial tachyarrhythmias at the 6-month follow-up, but it more than halved atrial arrhythmia related hospitalization and cardioversion rates during the blanking period.