Efficacy of intravenous disopyramide in acute cardiac arrhythmias.

The efficacy of intravenous disopyramide was studied during 200 episodes of supraventricular and ventricular arrhythmias in 160 patients, mainly presenting with acute myocardial infarction or cardiac failure. Disopyramide 50 mg was administered in a few seconds and any remaining dose within 2 to 5 min. The overall success rate was 80.5%. Intravenous disopyramide was more effective in patients with ventricular arrhythmias (85%) than in those with supraventricular arrhythmias (76%). Dose dependent prolongation of the PR interval, QRS time and the QT interval occurred in 16.32 and 20% of the cases, respectively. The adverse effects were aggravation of the arrhythmias, decrease of blood pressure and anticholinergic activity.