Abnormalities of the electrocardiogram in hereditary myopathies.

Cardiac as well as skeletal muscle is affected in the severe X-linked recessive form of Duchenne muscular dystrophy. Clinically this is evidenced by persistent tachycardia, arrhythmias; non- specific murmurs and sudden death from cardiac failure is common in this disorder. Histological evidence of cardiac muscle involvement includes variation in fibre size, hyalinization, fatty infiltra- tion, and connective-tissue proliferation. Such histological changes in cardiac muscle have been observed in patients who did not necessarily have any symptoms of heart disease during life (Globus,