[Observations on varions electrovectocardiographic aspects of the W-P-W syndrome].

The purpose of this study was to clarify certain electrovectorcardiographic aspects suggestive of heart disease associated with W-P-W syndrome. Seventy-six vectorcardiograms with W-P-W features were analyzed. The curves were obtained by Grishman's cube system and in 8 cases by Frank's method, as well. In addition, the conventional electrocardiograms corresponding to 55 vectorcardiograms, were studied. Not all the electrocardiographic and vectorcardiographic tracings were recorded simultaneously. The W-P-W syndrome was classified as type A when the electrical records suggested a pre-excitation phenomenon in the left postero-superior septal mass, probably with a partial "wave jumping" toward the right anterior septal mass. The W-P-W syndrome was judged to be of type B when the electrical tracings showed a pre-excitation in the right anterior septal mass, probably with a partial "wave jumping" toward the left posterior septal mass. The results of this study permit the following conclusions: 1. It seems justified to assert that the calssification of the W-P-W syndrome must be realized deductively on the basis of the sequence of the ventricular activation and of the heart position. 2. An interval of 30 msec. or more between the end of initial slurring and the vertex or middle point of the R loop permits inferring the coexistence of left ventricle hypertrophy. 3. The presence of an inactivable zone due to myocardial infarction should be suspected on the basis of segmentary irregularities or distortions of the electrical curves, while extensive deformations are more suggestive of myocardiopathy. 4. The duration of terminal slurrings does not depend on that of the initial ones. However, when the initial slurrings are very prolonged, the terminal ones are relatively short. 5. In the presence of W-P-W syndrome, the primary ventricular repolarization changes cannot be considered as pathognomonic of any associated cardiopathy because they are often provoked by drugs.