The acute haemodynamic effects of intravenous enalaprilic acid (MK422) in patients with left ventricular dysfunction.

Intravenous enalaprilic acid (2.5 mg) was given to 11 patients with stable cardiac failure (NYHA functional class II-IV). Reductions in mean right atrial, pulmonary artery and pulmonary capillary wedge pressure of 25%, 18% and 30% respectively (P less than 0.01), were observed. Cardiac output rose by 13% (NS) and mean blood pressure fell by 20% (P less than 0.01) with a decrease in systemic vascular resistance of 24% (P less than 0.01). Heart rate was unaltered. The haemodynamic effects correlated with control plasma renin activity (r = 0.78, P less than 0.01). Marked hypotension occurred in several subjects but no other side-effects were noted. The rapid onset of action and mixed venous and arteriolar dilating activity of intravenous enalaprilic acid may be an advantage in some clinical situations where parenteral vasodilating therapy is required.