Systemic and renal effects of enalapril and its effects on cardiac mass.

Enalapril is a new angiotensin converting enzyme (ACE) inhibitor and has been shown to be of benefit in the treatment of both renovascular and essential hypertension. We have studied the systemic and renal haemodynamic, biochemical and cardiac adaptive changes induced by this agent in eight patients with essential hypertension before and after 12 weeks of therapy. Mean arterial pressure fell from 110 to 90 mmHg (P less than 0.01) and this was mediated through a fall in total peripheral resistance, cardiac index and heart rate remaining unchanged. Renal plasma flow rose in six patients. Renal vascular resistance fell in all patients (P less than 0.01). Left ventricular mass index was reduced from a mean of 166 +/- 29 to 117 +/- 8 g/m2 (P less than 0.05) and systolic ventricular function remained unchanged. Thus, enalapril lowers arterial pressure by reducing total peripheral resistance, has favourable haemodynamic effects on the kidney, and produces a reduction in left ventricular mass within three months of the start of therapy.