A double-blind, placebo-controlled trial comparing the antiarrhythmic effects of
lidocaine (given intravenously as a bolus injection of 100 mg followed by an infusion of 2 mg min-1) and
propafenone (given as a bolus of 105 mg followed by 300 mg orally every 8 h) was conducted in the first 24 h following acute
myocardial infarction. Analysis of ventricular arrhythmias was carried out by Holter recordings. The three treatment groups,
propafenone (36 patients),
lidocaine (28 patients), and placebo (25 patients), did not differ with respect to age, gender, prevalence of previous
infarction, delay from the onset of
pain to hospitalization, clinical features on entry (the patients with
heart failure or malignant arrhythmias were excluded), site of acute
myocardial infarction, or CPK peak. A decrease in the number of ventricular
premature beats was noted with
lidocaine, but was not statistically significant. The analysis of the first 8 h showed trends suggesting that only
lidocaine could suppress complex arrhythmias, couplets and
ventricular tachycardia. The drugs were well tolerated. Mean plasma concentrations of
propafenone and
lidocaine were 517 +/- 464 ng ml-1 and 3.84 +/- 1.10 mg l-1, respectively. In conclusion, this study does not favour the use of
propafenone as an alternative to
lidocaine therapy during the acute phase of
myocardial infarction.