Intravenous amiodarone decreases the duration of atrial fibrillation associated with acute myocardial infarction.

PURPOSE: Atrial fibrillation (AF) is a fairly common complication of acute myocardial infarction (AMI). The aim of this study was to examine the safety and efficacy of intravenous amiodarone in converting AF associated with AMI.

METHODS: Seventy patients with AMI complicated with AF were prospectively divided into 3 groups: a) In group D (n = 26), 0.75 mg digoxin was administered intravenously and thereafter as needed, b) In group AM (n = 16), 300 mg of amiodarone was infused over 2 hours followed by 44 mg/hour for up to 60 hours or until sinus rhythm was restored, c) In group D + AM (n = 28), 0.75 mg of digoxin was administered (as in group D) for the initial 2 hours followed by amiodarone infusion as in group AM.

RESULTS: Sinus rhythm was restored: a) by the end of the 2nd hour in 9/26 patients from group D, 4/16 from group AM, and 10/28 from group D + AM (p = NS), b) by the end of the 96th hour, in 18/26 patients from group D, and in all patients from group AM and groupd D + AM. The corresponding duration of AF was 51 +/- 34 hours, 17 +/- 15 hours and 9 +/- 13 hours, respectively (F = 15.4, p < 0.001). AF recurred in 9/26, 5/16 and 1/28 patients of groups D, AM and D + AM, respectively (p = 0.026). The required dosage of amiodarone was lower in the D + AM group than in the AM group (603 +/- 563 mg versus 1058 +/- 680 mg, p = 0.037).

CONCLUSIONS: Intravenous amiodarone was well tolerated in patients with AMI complicated by AF and was effective in decreasing the duration of AF. However, the combination of amiodarone and digoxin was superior to amiodarone alone in restoring sinus rhythm faster, maintaining sinus rhythm longer, and allowing the use of a lower cumulative amount of amiodarone.