Cardioversion of Post-Ablation Atrial Tachyarrhythmia with Ibutilide and Amiodarone: A Registry-Based Cohort Study.

Patients with recurrence of atrial tachyarrhythmia after catheter ablation for atrial fibrillation or atrial flutter constitute a rapidly growing cohort, but study-driven treatment recommendations are lacking. The present study aimed to compare the cardioversion success of ibutilide and amiodarone in patients with post-ablation atrial tachyarrhythmia. We included all episodes of post-ablation atrial tachyarrhythmia in patients treated with either intravenous ibutilide or amiodarone at an academic emergency department from 2010 to 2018. The primary endpoint was the conversion to sinus rhythm. The conversion rates were stratified by arrhythmia type, and multivariable cluster-adjusted logistic regression was used to estimate the effect of ibutilide and amiodarone on cardioversion success, given as the odds ratio (OR) with 95% confidence intervals (95% CI). In total, 109 episodes of 72 patients were analyzed. The conversion rates were 37/49 (76%) for ibutilide and 16/60 (27%) for amiodarone. Compared to amiodarone, ibutilide was associated with higher odds of conversion (multivariable cluster-adjusted OR 5.6, 95% CI 1.3-24.3). The cardioversion success of ibutilide was the highest in atrial flutter (crude OR 19.5, 95% CI 3.4-112.5) and focal atrial tachycardia (crude OR 8.3, 95% CI 1.5-47.2), but it was less pronounced in atrial fibrillation (crude OR 4.5, 95% CI 1.2-17.2). Randomized trials are warranted to confirm our findings.