BACKGROUND: It is unclear whether acute conversion of atrial fibrillation (AF) with anti-arrhythmic drugs following cardiac surgery restores and/or maintains sinus rhythm or reduces hospital length of stay (LOS). MATERIAL/METHODS: A randomized prospective pilot study was conducted in 2 teaching hospitals from 3/28/98 to 8/2/99 to study the effect of the early use of ibutilide or propafenone on the duration of AF, rhythm at discharge, and LOS. A total of 42 stable patients with new AF after surgery were randomized to oral propafenone (600mg, single dose; n=20), ibutilide (1 mg up to 2 doses if necessary; n=10), or rate control only (n=12). Agents used for rate control were left to the discretion of the primary physician but beta-blockers were encouraged. RESULTS: Pre-randomization distribution of diabetes, CHF, previous AF, and the use of beta-blockers were similar in all groups. At 24 hours 0%, 65% and 34% of patients in the ibutilide (p=0.01), propafenone (p=ns), and rate control groups respectively remained in AF. Although ibutilide decreased AF duration, recurrence rates were 90%, 41%, and 58% in those groups (p=ns compared to rate control). Of the 3 patients who did not convert, all received propafenone. There was no difference in LOS or rhythm at discharge. CONCLUSIONS: Ibutilide but not propafenone decreases the duration of AF after cardiac surgery and neither appears to affect LOS or rhythm at discharge. This data suggests that post operative AF is transient and routine anti-arrhythmic therapy is not necessary for the majority of patients.

Keywords: Atrial Fibrillation - etiology, Propafenone - therapeutic use