Cardiac care in Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) encompasses early skeletal muscle involvement with myocardial disease characterized by progressive fibrosis and the gradual development of dilated cardiomyopathy, which become almost universal in adulthood and may lead to heart failure. These symptoms, together with respiratory failure, represent a major cause of morbidity and mortality. A structured management pathway is therefore essential: electrocardiography (ECG) and echocardiography at diagnosis and annually thereafter, with increasing use of cardiac magnetic resonance imaging (CMR) to detect early fibrosis (late gadolinium enhancement) and blood biomarkers of heart failure such as B-type natriuretic peptide (BNP) or NT-proBNP. Clinical recognition of heart failure is often delayed and tends to occur at advanced stages; similarly, atrial and ventricular arrhythmias can arise, generally later in the course of the disease. Treatment is based primarily on prevention by the early initiation of heart failure medications: an angiotensin-converting enzyme (ACE) inhibitor no later than age 10 years; a mineralocorticoid receptor antagonist when CMR shows fibrosis; and a beta-blocker in cases of symptomatic tachycardia. Corticosteroids started early for skeletal and respiratory muscles also appear to delay cardiomyopathy in a preventive setting. Curative treatment, for patients with a left ventricular ejection fraction of <50%, should follow international heart failure guidelines with quadruple therapy and the fastest feasible up-titration. Mechanical circulatory support may be discussed on a case-by-case basis. Innovative therapies, notably microdystrophin gene therapy, can be complicated by myocarditis or early direct myocardial injury, necessitating specific cardio-immunology follow-up.