Intrinsic alterations of diaphragm muscle in experimental cardiomyopathy.

Abstract Diaphragmatic function was investigated in the cardiomyopathic Syrian hamster (CSH) from the dilated Bio 53:58 strain, after long-term therapy with the angiotensin-converting enzyme inhibitor perindopril. Twenty-two 1-month old CSHs were treated during a 5-month period by either oral gavage with perindopril (1 mg/kg/day) ( n = 11) or placebo ( n = 11). Control hamsters from the F1B strain received placebo ( n = 7). Mechanical properties were studied in isolated diaphragm strips electrically stimulated in both twitch and tetanic conditions. Compared with F1B control hamsters, peak active tension and positive (dPdtmax) and negative (−dPdtmax) peaks of isometric tension derivative were significantly depressed in placebo treated CSHs. Compared with placebo-treated CSHs, peak active tension was significantly higher in perindopril-treated CSHs in both twitch (25 ± 4 vs 16 ± 1 mN/mm 2 ; p 2 ; p p p p p