Myocardial fibrosis burden predicts left ventricular ejection fraction and is associated with age and steroid treatment duration in duchenne muscular dystrophy

Background-Patients with Duchenne muscular dystrophy exhibit progressive cardiac and skeletal muscle dysfunction. Based onprior data, cardiac dysfunction in Duchenne muscular dystrophy patients may be influenced by myocardial fibrosis and steroidtherapy. We examined the longitudinal relationship of myocardial fibrosis and ventricular dysfunction using cardiac magneticresonance in a large Duchenne muscular dystrophy cohort.Methods and Results-We reviewed 465 serial cardiac magnetic resonance studies (98 Duchenne muscular dystrophy patientswith 7≥4 cardiac magnetic resonance studies) for left ventricular ejection fraction (LVEF) and presence of late gadoliniumenhancement (LGE), a marker for myocardial fibrosis. LVEF was modeled by examining LGE status, myocardial fibrosis burden (asassessed by the number of LGE-positive left ventricular segments), patient age, and steroid treatment duration. An age-only modeldemonstrated that LVEF declined 0.58±0.10% per year. In patients with both LGE-negative and LGE-positive studies (n=51), LVEFdid not decline significantly over time if LGE was absent but declined 2.2±0.31% per year when LGE was present. Univariatemodeling showed significant associations between LVEF and steroid treatment duration, presence of LGE, and number of LGEpositiveleft ventricular segments; multivariate modeling showed that LVEF declined by 0.93±0.09% for each LGE-positive leftventricular segment, whereas age and steroid treatment duration were not significant. The number of LGE-positive left ventricularsegments increased with age, and longer steroid treatment duration was associated with lower age-related increases.Conclusion-Progressive myocardial fibrosis, as detected by LGE, was strongly correlated with the LVEF decline in Duchennemuscular dystrophy patients. Longer steroid treatment duration was associated with a lower age-related increase in myocardialfibrosis burden.