The T loop in normal children

The Frank vectorcardiogram and the electrocardiogram in Duchenne progressive muscular dystrophy

Electrocardiograms and Frank vectorcardiograms from 44 patients with classical childhood progressive muscular dystrophy (Duchenne type) were analyzed. Seventy-seven per cent had definite electrocardiographic abnormalities. All had one and usually several vectorcardiographic abnormalities. Abnormalities in orientation, magnitude, or both, of the planar and spatial ventricular gradients were the most consistent of the vectorcardiographic abnormalities and were observed in 95% of the patients. This finding is of significance if this vector theoretically reflects diffuse myocardial disease at the cellular level. QRS changes, in general, reflected the relatively greater loss of posterior ventricular force with consequent exaggeration of anterior ventricular force. There was no demonstrable relationship between the electrocardiographic and vectorcardiographic abnormalities with the age of the patient and the severity and rapidity of clinical progression of the disease in patients less than 16 years of age. This study suggests that the vectorcardiogram may be a useful diagnostic adjunct to the standard electrocardiogram in the study of the cardiomyopathy of progressive muscular dystrophy in childhood.