Lack of effect of amiodarone on survival after extensive infarction. Polish Amiodarone Trial.

Background: The purpose of this study was to elucidate whether the reduction of mortality with amiodarone after myocardial infarction depended on ejection fraction.

Methods: The data from the Polish Amiodarone Trial were analysed retrospectively. Patients with acute myocardial infarction and contraindications to beta-blockers were randomized on days 5-7 after admission to receive amiodarone (n = 305) or placebo (n = 308). Short and long-term (46 months) mortality were analysed comparing the groups with impaired (ejection fraction < 40%) and preserved (ejection fraction > or = 40%) left ventricular function. A subset of patients (n = 523) with available echocardiograms were subjected to this analysis.

Results: Long-term and sudden cardiac mortality were significantly reduced with amiodarone in the group of patients with ejection fraction > or = 40% (amiodarone versus placebo, respectively: 9.1 versus 16.5%, P < 0.05; 3.4 versus 8.2, P < 0.05). No beneficial effect of amiodarone was observed in the group with low ejection fraction (cardiac and sudden cardiac mortality: amiodarone versus placebo, 20.8 versus 19.3% and 7.8 versus 5.7% respectively). One-year mortality also revealed a favourable trend only in amiodarone-allocated patients with ejection fraction > or = 40%.

Conclusion: Amiodarone decreased long-term and sudden cardiac mortality after myocardial infarction only in patients with preserved left ventricular function. No benefit was observed in patients with decreased ejection fraction.