Intravenous disopyramide in myocardial infarction: a haemodynamic study.

Disopyramide (2 mg/kg intravenously in 10 minutes) was administered to 14 patients with myocardial infarction within 36 hours of their infarct. Heart rate (HR) increased significantly five minutes after completion of the injection, but profound tachycardia was not seen. Mean wedge pressure (WP) rose and stroke volume (SV) fell. Disopyramide therefore showed a negative inotropic effect on the heart. Systemic vascular resistance (SVR) increased but blood pressure was not significantly altered. Diastolic and mean pulmonary arterial (PA) pressure was also increased by disopyramide. Peak plasma disopyramide level was reached five minutes after injection. The implications of the haemodynamic effects of disopyramide are discussed.