Effects of early and late therapy with perindopril on survival and myocardial inotropic state in experimental dilated cardiomyopathy.

We wished to test (a) whether single-drug therapy with a low dose of the angiotensin-converting enzyme (ACE) inhibitor perindopril has the capacity to improve early survival of the cardiomyopathic Syrian hamster (CSH); (b) whether early treatment with perindopril modifies CSH survival to a greater extent than perindopril treatment initiated later in the course of the disease; and (c) the effects of early and late perindopril therapy on the intrinsic contractility of left ventricular (LV) papillary muscle. We studied CSH from the Bio 53.58 dilated strain (n = 76), in which myocardial necrosis is known to develop from age 30 days, whereas congestive heart failure (CHF) is observed only after age 6 months. Animals were randomly assigned to three groups. In early-treated animals, perindopril (1 mg/kg body weight once daily in distilled water) was administered by force-feeding from age 1 month to 9 months (PE1, n = 21). Animals receiving delayed treatment received distilled water from age 1 month to 6 months, followed by 1 mg/kg body weight from age 6 to 9 months (PE2, n = 34). Controls received distilled water from age 1 month to 9 months (C, n = 21). At endpoint (9 months), mechanical properties of LV papillary muscles and serum ACE activity were studied in a subgroup of 32 CSH (C, n = 8; PE1, n = 10; and PE2, n = 14). Maximum unloaded shortening velocity, maximum extent of systolic shortening in twitch with preload only, and normalized peak of isometric active force were measured.(ABSTRACT TRUNCATED AT 250 WORDS)