HeartMattersPH
UP-PGH Division of
Cardiovascular Medicine
By Stephanie Palacios and Aisen Cabujat-Bumanglag
chief complaint: dyspnea
A 19-year-old male with an 8-year history of progressive lower limb weakness, later involving the upper extremities, presented with exertional dyspnea, orthopnea and paroxysmal nocturnal dyspnea . Family history was significant for Becker muscular dystrophy in two maternal cousins and a brother who died from cardiomyopathy. He was referred for cardiac evaluation after echocardiography showed reduced systolic function.
CRACK THE CASE
Early institution of guideline-directed medical therapy (GDMT)—ACE inhibitors or ARBs, beta-blockers, MRAs, and SGLT2 inhibitors—has been shown to delay fibrosis progression and improve survival (Marci et al., 2024; Keselman et al., 2025). Arrhythmia surveillance and family genetic counseling are essential components of management. Emerging therapies, including TRPV2 inhibition (tranilast) and gene-based strategies, are under investigation (Matsumura et al., 2025).
Discussion
Becker muscular dystrophy (BMD) is an X-linked recessive dystrophinopathy caused by in-frame deletions or duplications in the DMD gene, leading to partially functional dystrophin. Unlike Duchenne muscular dystrophy, BMD presents later and progresses more slowly. However, cardiac involvement is frequent and may determine prognosis. Up to 80% of patients develop cardiomyopathy by age 40, and cardiac death remains the leading cause of mortality (Gishto et al., 2024; Straub et al., 2023).
Cardiac manifestations include progressive LV dysfunction, fibrosis (often inferolateral), arrhythmias, and heart failure symptoms. Cardiac MRI with late gadolinium enhancement (LGE) is the most sensitive test for early detection, often showing subepicardial fibrosis even before a decline in EF. In this patient, LGE in the anterolateral and inferolateral walls confirmed non-ischemic myocardial injury typical of BMD cardiomyopathy.
Clinical Pearls
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Q: What is the earliest marker of cardiac involvement in BMD?
A: Subepicardial fibrosis on cardiac MRI, particularly in the inferolateral wall, often precedes systolic dysfunction.
Reference :
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Marci, M., D’Amario, D., Castiglione, V., et al. (2024). Cardiomyopathy in non-ambulatory muscular dystrophy patients: clinical course and outcomes. Cardiology and Therapy, 13(1), 1–17. https://doi.org/10.1007/s40119-023-00315-7
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Braunwald, E. (2022). Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine (12th ed.). Elsevier.
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Q: How does BMD cardiomyopathy differ from dilated cardiomyopathy?
A: In early disease, LV dimensions are normal despite global hypokinesia or regional fibrosis.
2023 ESC Guidelines for the Management of Cardiomyopathies. European Heart Journal, 44(35), 3217–3335. https://doi.org/10.1093/eurheartj/ehad393
Straub, V., Murphy, A., Vissing, J., et al. (2023). An update on Becker muscular dystrophy. The Lancet Neurology, 22(8), 730–743.
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Q: When should cardiac screening begin in BMD?
A: Echocardiography at diagnosis or by age 6, every 2 years until 10, then annually
2023 ESC Guidelines for the Management of Cardiomyopathies. European Heart Journal, 44(35), 3217–3335. https://doi.org/10.1093/eurheartj/ehad393
Straub, V., Murphy, A., Vissing, J., et al. (2023). An update on Becker muscular dystrophy. The Lancet Neurology, 22(8), 730–743.
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Q: What is the cornerstone of management for BMD-related cardiomyopathy?
A: Early initiation of GDMT—ACEi/ARB, beta-blocker, MRA, and SGLT2 inhibitor—to delay progression of fibrosis and HF.
Reference :
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Q: What are the prognostic implications of late gadolinium enhancement (LGE)?
A: Presence of LGE predicts EF decline, arrhythmias, and higher risk of adverse cardiac outcomes.