[The evolution of cardiac impairment in Duchenne's muscular dystrophy. Electrovector-cardiographic, polycardiographic and echocardiographic aspects (author's transl)].

The Authors have submitted to an electrocardiographic, vectorcardiographic, mechanocardiographic and echocardiographic investigation 4 cases with Duchenne's disease, which had already been studied by the Authors several years before. The longitudinal study has demonstrated, above all, the striking capacity of the electrocardiographic aspects of the disease to evolve from a normal to a "pseudo-necrotic" pattern. Such evolution, among other things, provides an important argument against the interpretation that attributes the electrocardiographic and vectorcardiographic changes in the initial stages of the disease to a persistence of a QRS loop of infantile type on a genetic basis. But for rare exceptions, the systolic time intervals and kinetocardiogram, which showed early indicative changes on the first examination, have successively shown easily predictable behavior considering the poor cardiovascular conditions of the patients on the second examination. The echocardiogram has proved useful in demonstrating the morphological and functional changes of the ventricular walls and of the interventricular septum, besides the eventual associated mitral valve prolapse. The echocardiographic evaluation of the left ventricular performance in quantitative terms, however, seems somewhat unreliable owing to the difficulty of obtaining technically good images, due to the thoracic deformity. The dystrophic changes recently observed in the myocardium even at ultrastructural level can probably explain not only the electrocardiographic and vectorcardiographic abnormalities but also the kinetocardiographic and echocardiographic changes. Among the above mentioned theoretical and practical considerations the possibility should be underlined that some cases of cardiomyopathy labelled as "primary" are in fact unrecognized dystrophic cardiomyopathies.