ANGIOTENSIN-CONVERTING ENZYME-INHIBITION AND SALT IN EXPERIMENTAL MYOCARDIAL-INFARCTION

It is well known that angiotensin-converting enzyme inhibitors attenua te progressive ventricular enlargement or hypertrophy after myocardial infarction and that cardiac angiotensin-converting enzyme activity is increased in the rat model of myocardial infarction. Tn this study, t o determine whether the beneficial effects of angiotensin-converting e nzyme inhibition on cardiac hypertrophy after myocardial infarction ar e due to a reduction in ventricular afterload or to inhibition of card iac angiotensin-converting enzyme, we used sodium loading during angio tensin-converting enzyme inhibition. The rat model of myocardial infar ction was treated with a vehicle, 1% saline, as drinking fluid, perind opril (2 mg/kg/day), or 1% saline as drinking fluid plus perindopril ( 2 mg/kg/day) for 6 weeks. Perindopril reduced blood pressure, prevente d cardiac hypertrophy, and inhibited cardiac angiotensin-converting en zyme. The effects of perindopril on blood pressure and cardiac hypertr ophy were abolished by sodium loading, which did not alter the degree of cardiac angiotensin-converting enzyme inhibition. Thus the actions of perindopril on cardiac hypertrophy depend more on blood pressure re duction than on cardiac angiotensin-converting enzyme inhibition in th e rat model of myocardial infarction.