Clinical studies of enalapril treatment for patients with severe congestive heart failure.

The clinical efficacy of enalapril was investigated in 21 patients with severe heart failure. For each subject, the following parameters were compared before and one month after enalapril maintenance treatment. NYHA functional class, Killip's class, cardiothoracic ratio (CTR), left ventricular (LV) function estimated by echocardiography and gated equilibrium radionuclide angiography, Holter ECG recordings, serum digoxin concentration (SDC), plasma remin activity, plasma aldosterone concentration, plasma norepinephrine concentration (PNE), etc. Short- and long-term hemodynamic responses to enalapril were also studied, with simultaneous measurement of enalapril concentration by radioimmunoassay. After maintenance therapy, patients showed a significant improvement as judged by NYHA functional class, Killip's class, and CTR. The LV fractional shortening and the ejection fraction significantly increased. The frequency of ventricular tachycardia showed a significant tendency to decrease after the therapy. The SDCs were unchanged, which indicates no pharmacokinetic drug interaction between digoxin and enalapril. Hemodynamic assessment showed a reduction in systemic vascular resistance, a reduction in mean blood pressure, and an increase in the cardiac index. No major side effects were observed during the study period. According to a multivariate analysis, the coefficient of determination of PNE was the highest for the final global improvement rating. This may reflect the neurohormonal improvement of congestive heart failure by enalapril therapy. In conclusion, enalapril is recommended for treating patients with severe CHF.