[Evolution of ventricular depolarization in the acute phase of inferior and posteroinferior myocardial infarction (author's transl)].

Twenty-five patients, hospitalized within 24 hours from the beginning of the precordiaglia due to acute diaphragmatic infarction, with or without a posterior extension, underwent the ECG and VCG recordings for the first consecutive twenty days and on the fortieth day, in order to study the development of ventricular depolarization. To diagnose an infarction of the diaphragmatic and posterior walls the usual ECG and VCG paramaters were used; the ECG was found to be less useful above all for the difficulty of measuring the variations, in the loss of the electrical forces. The electrodes were always placed in the same points suitably signed. Several evolutive modalities of the diaphragmatic infarction were observed; in 52% of the cases the loss of the inferior electrical forces reaches its maximum expression quickly, then it remains almost constant. In 12% of the cases the necrosis increases very clearly, tardily, between the ninth and fourteenth day. In 24% a precocious reduction of the electrical extension of the infarction on the eighth-twelfth day is observed. In 12% of the cases there are irregular oscillations during the whole acute phase. In all cases more or less stressed daily or cyclic oscillations were present. In nine cases an extension of the infarction to the posterior wall was evident; among these in five, two peaks are present; in two an initial increase, in the other two an initial decrease of the electrical extension of the necrosis; then, more or less stressed daily or cyclic oscillations. In another nine cases a single reading of the tracings do not let us diagnose a posterior extension; this is possible only through an "in series" reading. The clinical course and the humoral data do not give any contribution to the interpretation of the founded evolutive variabilities. The necrosis, therefore, must not be considered a zone of homogeneous and global stuffing, but composed of cellular groups in several and variable anatomo-metabolic situations conditioning the observed electrical instabilities.