Background: Recent clinical trials have shown increased, rather than decreased, mortality in patients treated with antiarrhythmic drugs after acute myocardial infarction.
Objective: To determine whether these findings had an impact on prescription of antiarrhythmic drugs after acute myocardial infarction.
Methods: We retrospectively analyzed the class I and III antiarrhythmic prescription data of 38,072 patients with acute myocardial infarction enrolled in three large randomized clinical trials endorsed by a highly representative sample (about 75%) of Italian coronary care units during the last 10 years. The first study was conducted in 1984 to 1985; the second, in 1988 to 1989; the pilot for the third, in 1991; and the third, in 1991 to 1994.
Results: Total class I and III antiarrhythmic prescriptions after acute myocardial infarction was halved during the last decade, from 11.9% at discharge and 14.4% at follow-up in 1984 to 1985 to 5.8% and 5.8%, respectively, in 1991 to 1994. The trend was independent of the different distributions in the three studies of the patients' characteristics associated with antiarrhythmic use (ie, age > or = 70 years, anterior acute myocardial infarction, ventricular fibrillation during hospitalization, and Killip class > or = 2 at randomization). The same decreasing trend was observed for each antiarrhythmic drug. The drug most widely used was amiodarone, accounting for about half of the antiarrhythmic prescriptions, followed by mexiletine hydrochloride and propafenone hydrochloride; flecainide acetate was dropped from the prescription list after the publication of the Cardiac Arrhythmia Suppression Trial results.
Conclusion: The negative results of the recent clinical trials on class I antiarrhythmic drug use after acute myocardial infarction have been rapidly transferred into routine clinical practice in Italy, since the proportion of patients who received class I and III antiarrhythmic drugs after acute myocardial infarction was halved from the early 1980s to the early 1990s.