Comprehensive Assessment of Cardiac Involvement in Muscular Dystrophies by Cardiac MR Imaging.

Muscular dystrophy is a group of genetically inherited diseases with irreversible and progressive muscle loss and is associated with cardiac involvement. Particularly in Duchenne and Becker dystrophies, cardiac disorders are the leading causes of mortality. Cardiovascular magnetic resonance imaging (CMR) can detect even incipient myocardial fibrosis (late gadolinium enhancement), which has prognostic significance in patients with preserved left ventricular function by echocardiogram and before the onset of symptoms. Early detection of cardiac abnormalities by CMR enables early cardioprotective treatment, leading to a better prognosis.

Myocardial Fibrosis Progression in Duchenne and Becker Muscular Dystrophy: A Randomized Clinical Trial.

Importance: In Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), interventions reducing the progression of myocardial disease could affect survival. Objective: To assess the effect of early angiotensin-converting enzyme (ACE) inhibitor therapy in patients with normal left ventricular function on the progression of myocardial fibrosis (MF) identified on cardiovascular magnetic resonance (CMR). Design, Setting, and Participants: A randomized clinical trial conducted in 2 centers included 76 male patients with DMD or BMD undergoing 2 CMR studies with a 2-year interval for ventricular function and MF assessment. In a non-intent-to-treat trial, 42 patients with MF and normal left ventricular ejection fraction (LVEF) were randomized (1:1) to receive or not receive ACE inhibitor therapy. The study was conducted from June 26, 2009, to June 30, 2012. Data analysis was performed from June 30, 2013, to October 3, 2016. Interventions: Randomization (1:1) to receive or not receive ACE inhibitor therapy. Main Outcomes and Measures: Primary outcome was MF progression from baseline to the 2-year CMR study. Results: Of the 76 male patients included in the study, 70 had DMD (92%) and 6 had BMD (8%); mean (SD) age at baseline was 13.1 (4.4) years. Myocardial fibrosis was present in 55 patients (72%) and LV systolic dysfunction was identified in 13 patients (24%). Myocardial fibrosis at baseline was an independent indicator of lower LVEF at follow-up (coefficient [SE], -0.16 [0.07]; P = .03). Among patients with MF and preserved LVEF (42 [55%]), those randomized (21 patients in each arm) to receive ACE inhibitors demonstrated slower MF progression compared with the untreated group (mean [SD] increase of 3.1% [7.4%] vs 10.0% [6.2%] as a percentage of LV mass; P = .001). In multivariate analysis, ACE inhibitor therapy was an independent indicator of decreased MF progression (coefficient [SE], -4.51 [2.11]; P = .04). Patients with MF noted on CMR had a higher probability of cardiovascular events (event rate, 10 of 55 [18.2%] vs 0 of 21 [0%]; log-rank P = .04). Conclusions and Relevance: In this 2-year, follow-up, randomized clinical trial of patients with Duchenne or Becker muscular dystrophy whose LVEF was preserved and MF was present as determined on CMR, ACE inhibitor therapy was associated with significantly slower progression of MF. The presence of MF was associated with worse patient prognosis. Trial Registration: clinicaltrials.org Identifier: NCT02432885.

Myocardial delayed enhancement by magnetic resonance imaging in patients with muscular dystrophy.

OBJECTIVES: This study sought to analyze whether cardiovascular magnetic resonance (CMR) can detect and quantify myocardial damage in the early stages of cardiomyopathy in muscular dystrophies (MD). BACKGROUND: Muscular dystrophy is a genetic disease that involves skeletal and cardiac tissues of humans. Cardiomyopathy is common, and death secondary to cardiac or respiratory diseases occurs early in life. Cardiovascular magnetic resonance is a reliable method for assessing global and regional cardiac function, allowing also for the detection of myocardial fibrosis (MF). METHODS: Ten patients with Duchenne or Becker dystrophies were studied by CMR. Physical examination, Chagas disease serological tests, electrocardiogram, chest radiograph, total creatine kinase, and Doppler echocardiogram were also obtained in all patients. RESULTS: Patients with MF had a lower ejection fraction than those without. Myocardial fibrosis (midwall and/or subepicardial) was observed in 7 of the 10 patients, and the lateral wall was the most commonly involved segment. There was moderate correlation between segmental MF and dysfunction. CONCLUSIONS: Cardiovascular magnetic resonance can identify MF and may be useful for detecting the early stages of cardiomyopathy in MD. Future work will be needed to evaluate whether CMR can influence cardiomyopathy and outcomes.