Effects of the quaternary ammonium compound OX-572 on ventricular tachyarrhythmias complicating acute myocardial infarction.

Patients with acute myocardial infarction who developed defined ventricular tachyarrhythmias were randomly allocated to two groups. The patients (n=34) in one of the groups received the quaternary ammonium compound N,N-bis (phenylcarbamoylmethyl) dimethylammoniumchloride (QX-572) intravenously as an infusion of 8 mg/kg body weight over 30 minutes. The patients in the other group (n=33) received saline and acted as controls. The analysis of arrhythmias was based on a continuous electrocardiogram recorded in parallel to routine monitoring during the 24 hours after the start of infusion. Only the detection of ventricular tachycardia or the development of ventricular fibrillation on routine monitoring could induce a change in antiarrhythmic treatment. The incidence of patients with ventricular tachycardia recorded was significantly lower in the QX-572 group (38%) than in the control group (73%). About half the number of patients with ventricular tachycardia recorded on the continuous electrocardiogram were also detected by means of routine monitoring. The number of patients with various types of ventricular premature contractions (1-5/min, greater than 5/min, paired, multifocal, R on T), ventricular tachycardia, and rapid idioventricular rhythm were compared within successive one-hour periods. For all types of ventricular tachyarrhythmias except rapid idioventricular rhythm there was a lower incidence of arrhythmias in the QX-572 group...