Dystrophinopathies may be associated with dilated cardiomyopathy, characterized by an impairment of left ventricular ejection fraction and potentially complicated by clinical heart failure. Conduction system disease and supraventricular or ventricular arrhythmias may also be present. The prevalence of cardiomyopathy is extremely high in Duchenne muscular dystrophy, intermediate in Becker dystrophy, and lower in female carriers. Cardiac follow-up is indicated in any patient with a mutation in the dystrophin gene, based on electrocardiogram and echocardiography, and must be closer, at least on a yearly basis, in patients with the highest cardiac risk. Systematic cardiac workups allow an earlier diagnosis of cardiac involvement and a prompt treatment. First-line treatments are angiotensin-converting-enzyme inhibitors and other heart failure treatments, which must be systematically initiated at the age of 10 years or earlier in Duchenne muscular dystrophy and regarding the identification of cardiac abnormalities in any patient with other dystrophinopathies.