Comparative investigation of the antiarrhythmic effect of propafenone (Rytmonorm) and lidocaine in patients with ventricular arrhythmias during acute myocardial infarction.

Propafenone, a new class I antiarrhythmic drug, given as a bolus injection followed by oral medication, or lidocaine were given to 20 consecutive patients admitted with chest pain suggesting acute myocardial infarction and showing high grades, i.e. multiform, pairs or R-on-T premature ventricular complexes or short runs of ventricular tachycardia. Before institution of therapy the mean number (+/- 1 SD) of premature ventricular contractions (PVCs) per hour was 169 +/- 123 in the lidocaine group and 324 +/- 440 in the propafenone group. During the next 24 hours lidocaine reduced the numbers of PVCs by 73% and propafenone by 75%. The mean number (+/- 1 SD) of 5-minute periods with high grade PVCs was 4.3 +/- 2.9 in the lidocaine group and 5.8 +/- 4.5 in the propafenone group. During therapy this number was equally reduced in both groups to 2.4. One patient in the lidocaine group developed ventricular fibrillation and three patients in the propafenone group were excluded because of increasing numbers of PVCs. One patient in the propafenone group showed a torsade-de-pointes ventricular tachycardia.