Plasma renin activity in infants with congenital heart disease.

Plasma renin activity was estimated in 11 infants with severe congestive heart failure. The infants had congenital heart disease with left to right shunts and were receiving diuretic treatment. Plasma renin activity was measured by radioimmunoassay of generated concentrations of angiotensin I. The mean (SD) plasma renin activity was 84 (21) ng angiotensin I/ml/hour, which is considerably above normal infant values. A hyperactive renin-angiotensin system may be detrimental in these patients. Angiotensin converting enzyme inhibitors may be of value in treating infants with severe congestive heart failure.