Response to ibutilide and the long-term outcome after catheter ablation for non-paroxysmal atrial fibrillation.

PURPOSE This study aimed to assess the relationship between the cardiac rhythm response to ibutilide infusion after pulmonary vein isolation and the recurrence of long-term atrial arrhythmias. METHODS One hundred and thirty-eight patients with non-paroxysmal atrial fibrillation who had had their first catheter ablation were retrospectively included. All patients whose atrial fibrillation did not terminate after pulmonary vein isolation were administered intravenous ibutilide (1.0 mg). Those with termination of atrial fibrillation after ibutilide administration were defined as responders (n = 86); those without termination of atrial fibrillation, as non-responders ( n = 52). The primary endpoint was any documented recurrence of atrial arrhythmia lasting more than 30 seconds after the initial catheter ablation. RESULTS Conversion of atrial fibrillation to sinus rhythm, directly or via atrial flutter, with ibutilide administration was achieved in 62.3% of patients. A longer duration of atrial fibrillation was associated with failed termination of atrial fibrillation (odds ratio 1.009, 95% confidence interval 1.002-1.017, p = 0.011). During a median follow-up period of 610 days (interquartile range 475-1 106) post ablation, non-responders (n = 24, 46.2%) had a higher recurrence rate of atrial arrhythmia than the responders (n = 26, 30.2%; log-rank, p = 0.011) after the initial catheter ablation. Multivariate Cox regression analysis revealed that non-responders (hazard ratio 1.994, 95% confidence interval 1.117-3.561, p = 0.020) was significantly correlated with recurrence of atrial arrhythmias. CONCLUSIONS In patients whose atrial fibrillation persisted after pulmonary vein isolation, the response to ibutilide administration could predict the recurrence of atrial arrhythmias after catheter ablation, which may be useful for risk stratification for recurrence of atrial fibrillation and individualised management of atrial fibrillation.