[The changes in renin-angiotensin-aldosterone system in acute myocardial infarction and the effects of converting enzyme inhibitor-captopril].

A serial measurements of plasma renin activity (PRA), serum angiotensin converting enzyme activity (ACE), concentrations of plasma angiotensin II (AII) and plasma aldosterone (Ald) in 38 consecutive patients with acute myocardial infarction (AMI) or suspected AMI showed that PRA, AII and Ald levels increased in patients with AMI, especially within first week after onset, and were significantly higher in those cases with severe complications. ACE kept in normal range in all subjects. After small dose captopril therapy, ACE and Ald decreased significantly, PRA and AII increased in 6 patients with AMI. Small dose captopril could cause remarkable blood pressure reduction, but no effect on heart rate. The results suggested that renin-angiotensin-aldosterone system was activated during AMI, especially in cases with severe complications. Captopril could inhibit this system partially.