Abnormalities of the electrocardiogram in female carriers of Duchenne muscular dystrophy.

The algebraic sum of the R and S waves (R-S) in the V(1) lead of the electrocardiogram has been found to be significantly greater in female carriers of X-linked Duchenne muscular dystrophy (but not in women with limb-girdle muscular dystrophy) compared with normal women of comparable age. A similar E.C.G. abnormality is found in affected boys, and possibly certain carriers have a latent cardiomyopathy and may even be predisposed to cardiac failure.