ORIGINAL ARTICLE: PDF OnlySweet Charles S.; Emmert, Scott E.; Stabilito, Inez I.; Ribeiro, Lair G. T.Journal of Cardiovascular Pharmacology: December 1987 - p 636-642 Free Abstract Summary: Vasodilating drugs such as angiotensin converting enzyme (ACE) inhibitors may extend life expectancy in patients with congestive heart failure (CHF). The purpose of this study was to evaluate whether long-term therapy (365 days) with enalapril (ENAL, an ACE inhibitor), would prolong life in rats with a healed myocardial infarction (MI), an experimental model with hemodynamic characteristics of CHF. Seven days after sham or coronary ligation, when the healing phase of MI was well underway. 132 rats (75 sham. 57 Ml) were randomized to receive either enalapril in the drinking water (17–25 mg/L, approximately 1.0 mg/kg/day) or tap water. The date of spontaneous death was recorded, and heart weight and MI size (by planimetry) were determined. Serum ENAL. total ACE concentration, and angiotensin and methoxamine pressor responses were quantified in 12 survivors. Long-term enalapril prolonged survival (p = 0.014) with a median 50% survival of 164 (164–165) days, compared to 84 (64–104) days in rats receiving tap water. There were twice as many MI rats alive at the end of one year on angiotensin converting enzyme inhibition (ACEI) therapy as compared to the untreated group. The average MI size (39–40%) was not different between groups, and there was a significant inverse correlation between date of death and MI size (r = 0.7–0.8) in both treatment groups. Cardiac hypertrophy was evident in all MI rats. Serum ENAL levels, after one year, were at the clinically relevant concentration (2.3 ng/ml) and total serum ACE (inhibitor removed) doubled to 4,300 nmol/h/ ml. The depressor response to bradykinin was enhanced, and the ratio of the pressor responses to angiotensin I/an-giotensin II were reduced, reflecting chronic ACE inhibition. This study demonstrates that long-term ACEI therapy prolongs survival in rats with chronic congestive heart failure © Lippincott-Raven Publishers.