[Immediate cardioversion of atrial fibrillation and atrial flutter lasting less than 90 days by ibutilide versus propafenone: a multicenter study]

Abstract

Objective: To compare the efficacy and safety of ibutilide versus propafenone in immediate cardioversion of atrial fibrillation (AF) and atrial flutter (AFL) lasted less than 90 days.

Methods: 212 consecutive patients suffering from AF or AFL all lasting less than 90 days that were diagnosed and treated in 5 medical centers were randomly assigned into two groups: ibutilide group (n = 107, including 75 AF cases and 32 AFL cases, receiving intravenous injection of ibutilide 1mg over 10 minutes) and propafenone group as control group (n = 105, including 76 AF cases and 29 AFL cases, receiving intravenous injection of propafenone 70 mg over 10 minutes). If AF/AFL still persisted 10 minutes after treatment, the above dose was repeated. The conversion rate within 1.5 hours and adverse effects within 4 hours were observed.

Results: (1) The conversion rate on AFL of the ibutilide group was 78.1%, significantly higher than that of the propafenone group (48.3%, P < 0.01), while no significant difference was observed in the conversion rate on AF (54.7% vs. 39.5%, P > 0.05) and the mean conversion time (P > 0.05). However the overall conversion rate on AFL and AF of the ibutilide group was 61.7%, significantly higher than that of the propafenone group (41.9%, P < 0.05). (2) The conversion rate on AF/AFL lasting less than 48 h was 65.9% in the ibutilide group, not significantly different from that of the propafenone group (55.7%), the conversion rate on AF/AFL lasting 3 approximately 30 d in the ibutilide group was 66.7%, significantly higher than that of the propafenone group (26.3%, P < 0.05), and the conversion rate on AF/AFL lasting 31 - 88 d was 50%, significantly higher than that of the propafenone group (0, P < 0.01). (3) There was no difference in the times needed for conversion between these 2 groups. (4) The most severe adverse effect in the ibutilide group was short run of ventricular tachycardia occurring in 5 cases among which 4 cases recovered simultaneously and one case recovered after accepting a bolus dose of 100 mg lidocaine. The most severe adverse effects in propafenone group were RR interval longer than 1.5 s (4 cases) and transient hypotension. An acute coronary event was also seen in propafenone group, however, unrelated to the experimental drug.

Conclusion: Intravenous administration of ibutilide in cardioversion of AF and AFL is safe and effective.