Acute and long-term response to enalapril in congestive failure.

Enalapril, a novel long acting angiotensin converting enzyme (ACE) inhibitor, was given orally to 12 patients with chronic heart failure (NYHA functional class III and IV) and cardiomegaly. The optimal dose averaged 17 mg given once-daily. Heart rate, systemic arterial blood pressure, pulmonary arterial pressure, right and left ventricular filling pressures and cardiac index were monitored during dose efficacy titration. Eleven patients were recatheterised 3 months later. After stabilisation of cardiac filling pressures, all patients had left ventricular filling pressures in excess of 20 mmHg. Enalapril increased cardiac index acutely by 34% but at 12 weeks follow-up, cardiac index was not different from control levels. Left ventricular filling pressure was reduced acutely by 36% and by 41% at 3 months. Heart rate, systemic arterial and right atrial pressures and plasma concentrations of aldosterone were reduced during the observation period. ACE activity was inhibited at the time of peak haemodynamic effect from 25.3 +/- 9.8 to 4.9 +/- 3.4 U/ml (P less than 0.01). Renin was markedly elevated. These changes were accompanied by marked and sustained clinical improvement and subjective well-being.