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Duchenne Muscular Dystrophy: Cardiomyopathy

Cardiac abnormalities are a significant cause of death and morbidity in patients with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), especially as boys with DMD are now living through their twenties. The clinical course of cardiomyopathy is usually prolonged (progressive decline in left ventricular function resulting in cardiac failure) although sudden death from an arrhthymia also occurs. Many patients do not show symptoms of cardiomyopathy due to their lack of physical activity, but early changes in cardiac function are apparent on cardiac imaging studies, e.g. echocardiogram or cardiac magnetic resonance imaging (MRI) study. Because changes in cardiac function are uncommon before the second decade of life, the Treat-NMD standards recommend a cardiology evaluation with an echocardiogram and electrocardiogram (ECG) at the time of diagnosis, then biannually until age 10 years, and annually thereafter unless progressive problems suggest the need for more frequent exams. A cardiology referral is also recommended before any major surgery. Clinical symptoms, when present, may include those associated with symptoms of congestive heart failure (edema, shortness of breath, orthopnea), reduced cardiac output (especially fatigue) and/or arrhythmias. Conversely, symptoms might not be present due to decreased skeletal muscle strength and decreased physical activity until very late in the course of the disease. With severe cardiomyopathy, thromboembolic events have been observed.
Of note, the mothers of boys with DMD/BMD may also be at risk for cardiac problems and should be evaluated by genetic testing to confirm carrier status. An ECG and echocardiogram should be performed by an adult cardiologist as well.
In addition to an ECG and an echocardiogram, some cardiologists may order a cardiac MRI instead of or in addition to those tests for better anatomical visualization. Cardiac MRI may show evidence of heart muscle scarring, which cannot be seen via echocardiogram. Decreased left ventricular ejection fraction on echocardiogram is the most common early finding of dilated cardiomyopathy.
Early diagnosis of dilated cardiomyopathy, based on echocardiographic findings and not clinical deterioration, and treatment are advised. Initial medication options include angiotensin converting enzyme (ACE) inhibitors, such as enalapril or lisinopril, and angiotensin receptor blockers (ARBs), such as losartan. These medications are also commonly used to treat high blood pressure, which that may be related to prolonged steroid exposure in boys with DMD. Other agents, such as beta-blockers, may be added in the setting of advanced dilated cardiomyopathy depending on cardiology preference and disease manifestations. Other medications, such as diuretics, may be added when a patient has signs or symptoms of congestive heart failure. Anti-arrhythmic therapy is sometimes needed as well. Left ventricular assist devices (LVADs) may increasingly be offered to boys in heart failure and in some cases, cardiac transplantation may be a possibility. There is also recent evidence suggesting that prolonged steroid therapy may be helpful in delaying the onset of cardiomyopathy. [Schram: 2013]

Resources

Practice Guidelines

TREAT-NMD, a neuromuscular network, has published a list of expert guidelines, including cardiology recommendations. See Standards of Care for Duchenne Muscular Dystrophy (TREAT-NMD)

Helpful Articles

McNally EM, Kaltman JR, Benson DW, Canter CE, Cripe LH, Duan D, Finder JD, Groh WJ, Hoffman EP, Judge DP, Kertesz N, Kinnett K, Kirsch R, Metzger JM, Pearson GD, Rafael-Fortney JA, Raman SV, Spurney CF, Targum SL, Wagner KR, Markham LW.
Contemporary cardiac issues in Duchenne muscular dystrophy. Working Group of the National Heart, Lung, and Blood Institute in collaboration with Parent Project Muscular Dystrophy.
Circulation. 2015;131(18):1590-8. PubMed abstract / Full Text

Angelini C.
Prevention of cardiomyopathy in Duchenne muscular dystrophy.
Lancet Neurol. 2015;14(2):127-8. PubMed abstract

Thrush PT, Flanigan KM, Mendell JR, Raman SV, Daniels CJ, Allen HD.
Visual diagnosis: chest pain in a boy with duchenne muscular dystrophy and cardiomyopathy.
Pediatr Rev. 2014;35(12):e64-7. PubMed abstract

Raman SV, Hor KN, Mazur W, Halnon NJ, Kissel JT, He X, Tran T, Smart S, McCarthy B, Taylor MD, Jefferies JL, Rafael-Fortney JA, Lowe J, Roble SL, Cripe LH.
Eplerenone for early cardiomyopathy in Duchenne muscular dystrophy: a randomised, double-blind, placebo-controlled trial.
Lancet Neurol. 2015;14(2):153-61. PubMed abstract / Full Text

Leung DG, Herzka DA, Thompson WR, He B, Bibat G, Tennekoon G, Russell SD, Schuleri KH, Lardo AC, Kass DA, Thompson RE, Judge DP, Wagner KR.
Sildenafil does not improve cardiomyopathy in Duchenne/Becker muscular dystrophy.
Ann Neurol. 2014;76(4):541-9. PubMed abstract / Full Text

Iodice F, Testa G, Averardi M, Brancaccio G, Amodeo A, Cogo P.
Implantation of a left ventricular assist device as a destination therapy in Duchenne muscular dystrophy patients with end stage cardiac failure: management and lessons learned.
Neuromuscul Disord. 2015;25(1):19-23. PubMed abstract

Authors

Authors: Richard Williams, MD - 9/2013
Lynne M Kerr, MD, Ph.D. - 9/2013
Reviewing Author: Meghan Candee, MD - 1/2017
Content Last Updated: 1/2017

Page Bibliography

Schram G, Fournier A, Leduc H, Dahdah N, Therien J, Vanasse M, Khairy P.
All-cause mortality and cardiovascular outcomes with prophylactic steroid therapy in Duchenne muscular dystrophy.
J Am Coll Cardiol. 2013;61(9):948-54. PubMed abstract