Echocardiographic assessment of left ventricular function in Duchenne's muscular dystrophy.

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Abstract
Left ventricular function was assessed echocardiographically in 13 children with Duchenne''s muscular dystrophy. Ejection fraction, mean velocity of circumferential fiber shortening, normalized left ventricular posterior wall velocity, maximal systolic endocardial velocity, and maximal diastolic endocardial velocity were determined manually by measuring directly from the echocardiographic tracings. The echocardiograms were then digitized and results computed in order to study the peak rates of change of dimension, the peak lengthening rates, the peak shortening rates, and the time relation between the mitral valve and left ventricular posterior wall movement in early diastole. All the systolic phase indices were within normal limits. Though maximal diastolic endocardial velocity (11.1 .+-. 3.2 cm/s = mean .+-. SD) was reduced in patients with Duchenne''s muscular dystrophy compared with normal controls (15.3 .+-. 3.2 cm/s), the peak rates of change of dimension and the peak lengthening rates were identical with normal subjects. The time relation between the mitral valve and left ventricular posterior wall movement was not significantly different from normal. The maintenance of this close time relation and the fact that the ventricle is filling normally, as evidenced by normal peak filling rates, suggest that the myocardial function is well preserved in children with Duchenne''s muscular dystrophy. The reduced maximal diastolic endocardial velocity may be the result of reduced overall movement of the heart within the thorax.