EFFECTS OF A NEW ANGIOTENSIN-CONVERTING ENZYME-INHIBITOR (IDRAPRIL) IN RATS WITH LEFT-VENTRICULAR DYSFUNCTION AFTER MYOCARDIAL-INFARCTION

We evaluated the effects of a new angiotensin-converting enzyme (ACE) inhibitor (idrapril) in terms of hemodynamics and ventricular remodeli ng after myocardial infarction in rats, The animals were randomly assi gned to four experimental groups. Myocardial infarction was induced by left coronary artery ligation in the first two groups treated with ei ther idrapril (300 mg kg(-1) day(-1)) or vehicle for 4 weeks after myo cardial infarction. Two groups of sham-operated rats were treated acco rdingly. Hemodynamics were measured, and the diastole-arrested hearts were analyzed morphometrically to quantify left ventricular (LV) remod eling and infarct size. In infarcted rats, idrapril reduced the arteri al systolic blood pressure (SEP) from 128 +/- 10 to 97 +/- 6 mm Kg (p < 0.05) and LV end-diastolic pressure (LVEDP) from 19 +/- 3 to 13 +/- 3 mm Hg (p < 0.01). The decrease in diastolic wall stress conferred by idrapril to infarcted rats (from 499 +/- 99 to 269 +/- 68 dynes mm(-2 ), p < 0.05) was mainly due to a reduction in LVEDP and, to a lesser e xtent, in LV volume. Idrapril also reduced body and heart weights as c ompared with those of vehicle-treated animals. Four-week treatment wit h idrapril initiated immediately after myocardial infarction reduced L VEDP and limited LV wall stress, a major prognostic factor for the pro gression toward chronic ventricular failure.