Cardiac impairment in Duchenne Muscular Dystrophy: A single-center retrospective experience

Objectives: Cardiomyopathy is the most common cause of mortality in boys with Duchenne Muscular Dystrophy (DMD) and early diagnosis is critical for timely initiation of cardioprotective therapies. In this study, we aimed to evaluate cardiac functions in patients with DMD and to determine the association between motor functions and the degree of cardiac impairment. Methods: A total of 51 boys with DMD evaluated between 2019 and 2022 were included. Clinical variables, including demographic features, family history of DMD, ambulatory status, genetic mutations, corticosteroid therapy, cardiac assessments (transthoracic echocardiography (TTE), 12-leads electrocardiogram (ECG), and cardiac magnetic resonance imaging (CMRI) if available) were retrospectively analyzed. Results: The mean age at DMD diagnosis and mean age at last cardiac evaluation were 39 months (1-88 months) and 91 months (12-213 months), respectively. Fourteen patients had a family history of DMD. At the last clinical assessment, 75% of the patients were ambulant. In the TTE, mean ejection fraction, shortening fraction, and left ventricular end-diastolic diameter were 67% (48-74), 36% (24-42), and 32mm (20-50), respectively. Prolonged QTC interval was observed in four patients. Cardiac MRI-derived EF was ≤55% in 38% and CMRI showed the presence of left ventricular wall hypokinesia in 25% and late-gadolinium enhancement in 25% of boys. Conclusion: Despite having normal baseline systolic function in TTE, variable degrees of systolic/diastolic dysfunction and focal myocardial fibrosis were detected by CMRI in our patients with DMD. Early detection of cardiac dysfunction with sensitive imaging modalities in DMD is critical for both disease monitoring and early interventions.
Keywords: DMD, cardiac magnetic resonance imaging, echocardiography, cardiomyopathy