Pathophysiology and Therapy of Cardiac Dysfunction in Duchenne Muscular Dystrophy

Daniel P. Judge; David A. Kass; W. Reid Thompson; Kathryn R. Wagner

Disclosures

Am J Cardiovasc Drugs. 2011;11(5):287-294. 

In This Article

4. β-Adrenoceptor Blockers

The use of β-adrenoceptor blockers (β-blockers) for non-syndromic asymptomatic cardiac dysfunction is less well established than the use ofACEinhibitors, though it has been shown to be useful. The REVERT (Reversal of Ventricular Remodeling with Toprol-XL) trial randomized 149 participants with EF <40%, mild left ventricular dilation, and no symptoms of heart failure (NYHA class I) to extended-release metoprolol succinate 200 mg daily (n = 48) versus 50 mg daily (n = 48) versus placebo (n = 53).[24] After 12 months, in the 200mg group, there was a 14±3mL/m2 decrease in end-systolic volume and a 6±1% increase in left ventricular ejection fraction (p < 0.05 vs baseline and placebo for both). In the 50 mg group, end-systolic and end-diastolic volumes decreased relative to baseline but were no different from volumes seen with placebo, whereas EF increased by 4±1% (p < 0.05 vs baseline and placebo).[24] This study was not designed or powered to detect differences in morbidity or mortality in asymptomatic DCM.

The use of carvedilol in people with DMD and cardiac dysfunction was recently reported.[25] In this study, 54 patients were included in an open-label analysis of carvedilol versus no β-blocker. The cohort included 41 patients who received carvedilol (mean age 23.2 years) and 13 who did not receive β-blockers (mean age 19.3 years, p = 0.041 for ages). Rates of survival and heart failure-free survival were higher in the cohort that received β-blockers. However, the average daily dose of carvedilol was low (7.85 mg/day), the participants were not randomized, and the groups compared were remarkably heterogeneous, all of which likely limit the conclusions regarding safety and efficacy of carvedilol in these patients.[25] A trial currently enrolling in Italy is comparing the efficacy of carvedilol versus ramipril in the prevention of cardiomyopathy in DMD (clinicaltrials.gov identifier: NCT00819845).

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