Identification of post acute myocardial infarction patients with potential benefit from prophylactic treatment with amiodarone. A substudy of EMIAT (The European Myocardial Infarct Amiodarone Trial)

Abstract

Aims. To perform a retrospective analysis of subgroups of patients enrolled into the European Myocardial Infarct Amiodarone Trial (EMIAT) in order to identify patients who might benefit from prophylactic amiodarone treatment and patients in whom amiodarone might be harmful. Methods. Baseline characteristics of the 1486 patients enrolled in EMIAT were used to investigate the all-cause mortality effect of amiodarone (intention-to-treat) in patients with a left ventricular ejection fraction 30-40% and < 30%, in patients with and without arrhythmia signs on Holter recordings, in patients with high and low baseline resting heart rate, in patients on and off beta-blocker treatment, and in a combination of these groups. Results. A univariate analysis suggested that all-cause mortality is reduced on amiodarone in patients with an ejection fraction < 30%, with arrhythmia on the initial Holter, on beta-blocker treatment, and with an increased initial heart rate. A trend towards an increase of all-cause mortality was noted in patients with an ejection fraction 30-40%, without arrhythmia on Holter, off beta-blockers, and with a low baseline heart rate. A multivariate analysis suggested that the univariate observations are mutually additive. Conclusions. The study might serve as a basis for future prospective trials where amiodarone could be tested in patients with a recent myocardial infarction, having a reduced left ventricular ejection fraction, a high initial heart rate, and taking beta-blockers.