Sustained haemodynamic effects of enalapril in left ventricular failure

Enalapril, a novel angiotensin converting enzyme inhibitor, was given orally to 12 patients with chronic heart failure (NYHA functional class III and VI) and cardiomegaly. Heart rate, systemic arterial blood pressure, pulmonary arterial pressure, right and left ventricular filling pressures and cardiac index were monitored during dose efficacy titration. The optimal dose averaged 17 mg given once-daily. All patients were recatheterized three months later. After stabilization of cardiac filling pressures, all patients had left ventricular filling pressures in excess of 18 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 three months. Heart rate, systemic arterial and right atrial pressures and plasma concentrations of aldosterone were reduced during the observation period. Renin was markedly elevated. These changes were accompanied by marked and sustained clinical improvement and subjective well-being.