Myocardial Fibrosis Associated With Decline in the Left Ventricular Function in Duchenne Muscular Dystrophy

According to recent study, progressive myocardial fibrosis is associated with a decline in the left ventricular function in patients with Duchenne muscular dystrophy. Longer steroid treatment duration is also associated with a lower age‐related increase in myocardial fibrosis burden, according to the study now published in the journal Pediatric Cardiology.

Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene. Cardiac dysfunction is a leading cause of both morbidity and mortality in DMD patients because of the left ventricular (LV) dilation and the development of depressed LV ejection fraction (LVEF), both of which are common with the disease. The mechanisms of the development of cardiac dysfunction in DMD remain poorly understood, but the presence of myocardial fibrosis may indicate progression of cardiac disease, with the late gadolinium enhancement (LGE) being a marker for myocardial fibrosis,

To address this clinical issue, in the study entitled “Myocardial Fibrosis Burden Predicts Left Ventricular Ejection Fraction and Is Associated With Age and Steroid Treatment Duration in Duchenne Muscular Dystrophy,” Michael D. Taylor, MD, PhD. From the Heart Institute, Cincinnati Children’s Hospital Medical Center in Cincinnati, and his colleagues, examined the relationship between LVEF and myocardial fibrosis burden in patients with DMD and investigated the associations with age and duration of steroid treatment. The researchers also tested the association of LGE to all‐cause death, heart transplant, LV assist device implantation, and arrhythmias.

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The researchers reviewed a total of 465 serial cardiac magnetic resonance studies (98 Duchenne muscular dystrophy patients with ≥4 cardiac magnetic resonance studies) for left ventricular ejection fraction (LVEF) and presence of late gadolinium enhancement (LGE). LVEF was modeled by examining LGE status, myocardial fibrosis burden (as assessed by the number of LGE‐positive left ventricular segments), patient age, and steroid treatment duration.

Results revealed that an age‐only model was related with an LVEF decline, and that the development of LGE is a strong marker for the progression of LV systolic dysfunction in DMD patients and that myocardial fibrosis burden correlates strongly with LVEF.

A longer steroid treatment duration was found to be associated with a lower age‐related increase in myocardial fibrosis burden. According to the researchers, these results support the theory that progressive fibrofatty myocardial replacement is a substrate for myocardial dysfunction in DMD patients. However, more studies are necessary to understand if the use of antifibrotic agents in DMD populations should be performed with myocardial fibrosis imaging and LVEF as therapeutic end points.