Duchenne Muscular Dystrophy: Cardiac Management

1. Duchenne Muscular Dystrophy:Cardiac Management

2. Introduction • Aim: early detection and treatment of deterioration in heart muscle function • Cardiac disease most often manifests as • Cardiomyopathy and/or • Cardiac arrhythmia • Progressive cardiomyopathy a major source of DMD/BMD morbidity – warrants further study • Clear onset of disease in myocardium before clinical symptoms • Surveillance and proactive management are key: a cardiologist must be in the care team • Family should have a copy of the latest assessments to show attending doctors

3. Surveillance: Baselines • Baseline evaluation of cardiac function at diagnosis or by 6 years at the latest, especially if possible without sedation • Clinical judgement should be used for patients under 6 requiring sedation • Incidence of echocardiograph abnormalities is low in children under 8-10 years, but where they do exist can affect clinical decision-making • Baseline echocardiogram also allows for screening for anatomical abnormalities(e.g. atrial/ventricular septal defects, patent ductus arteriosis) which may affect long-term cardiovascular function • Minimal evaluation should include, but is not limited to, and electrocardiogram (ECG) and echocardiogram

4. Surveillance: Annual Evaluation • Evaluation at least once every 2 years to the age of 10. • Annual complete cardiac assessments should begin at 10, or at onset of cardiac signs or symptoms if these occur earlier • Increased surveillance (at least every 6 months) required if non-invasive cardiac tests show abnormalities of ventricular function. • Drug treatment should be initiated, irrespective of the age at which they are detected

5. Treatment • First-line therapy: angiotension converting enzyme (ACE) inhibitors • Beta-blockers and diuretics also appropriate, and should follow published guidelines for management of heart failure • Recent clinical trial evidence supports the prophylactic treatment of cardiomyopathy with ACE inhibitors prior to signs of abnormal functioning: further studies awaited to allow firm recommendations.

6. Abnormalities (1) • Abnormalities of cardiac rhythm should be promptly investigated with Holder or event monitor recording, and should be treated • Sinus tachycardia is common in DMD, but also noted in systolic dysfunction. • New onset in absence of clear cause should prompt assessment including that of left-ventricular function • Those on steroids need additional cardiovascular attention, especially for hypertension which may necessitate an adjustment of steroid dose [TLN table 2 part 1]

7. Abnormalities (2) • Systemic arterial hypertension should be treated • Prevention of systemic thromboembolic events by anticoagulation therapy can be considered in severe cardiac dysfunction, but inappropriate in earlier cardiac dysfunction • Usefulness of internal cardiac defibrillator not established • With generally improved fitness of DMD patients, cardiac transplants may require consideration in future

8. References & Resources • The Diagnosis and Management of Duchenne Muscular Dystrophy, Bushby K et al, Lancet Neurology 2010 9 (1) 77-93 & Lancet Neurology 2010 9 (2) 177-189 • Particularly references, p186-188 • The Diagnosis and Management of Duchenne Muscular Dystrophy: A Guide for Families • TREAT-NMD website: www.treat-nmd.eu • CARE-NMD website: www.care-nmd.eu