Relation of myocardial disease to abnormalities of the ventricular complex of the electrocardiogram

Abstract

Sixty cases have been studied in attempting to determine a relation between the character of the ventricular complex of the electrocardiogram and the pathological findings in the ventricular myocardium. Of 13 cases with a normal ventricular complex, a normal myocardium was found in 7. In the other six there were slight morphological changes. Of 47 cases with abnormal ventricular complexes a normal myocardium was found in 9 (19 per cent). The abnormal features of the electrocardiograms in these 9 cases were similar to those found in other cases which revealed slight or moderate pathological changes in the myocardium. In the other 81 per cent of cases with abnormal ventricular complexes there were definite myocardial changes. When the electrocardiographic abnormality involved only the QRS group, the T-wave being normal, there were found only slight or moderate myocardial changes. Although there was, in general, an association of increased duration of QRS with cardiac enlargement, yet there were notable exceptions. When the T-wave was abnormal, with or without QRS abnormality, there was a great range in the extent and the degree of the myocardial changes discovered. A frequent but not constant association was seen between the coronary T-wave and focal myocardial lesions. There was a constant association between an elevated or depressed S-T interval and the finding of areas of acute myocardial degeneration, though not always with areas of infarction. The ventricular complex attributed to marked left ventricular hypertrophy affords an exception to this statement regarding the S-T interval. Right bundle-branch block occurred twice without morphological myocardial changes being discovered and three times with such changes. Left bundle-branch block occurred twice, each time associated with myocardial changes. A review of the literature showed a few comparable studies, all of which were in general agreement with these findings.