A Correlative Study of Postmortem, Electrocardiographic, and Spatial Vectorcardiographic Data in Myocardial Infarction

Abstract

The spatial vectorcardiograms (sVCG) and electrocardiogramns were studied with respect to the gross and microscopic data in 59 instances of myocardial infarction. Besides the early abnormalities in the QRS sf-loop frequently associated with the electrocardiographic Q of infarction, there were recognizable alterations in the sVCG associated with the anatomic location of the infaretion: lateral wall infarets shortened vectors in iiid-QRS sfi-loop, and posterior lateral basal infarction altered the terminal portion distinctively. The myocardial lesions included fresh infarets, solid scars, scattered fibrosis, and scar with interwoven intact muscle fibers. Where many normal-appearing fibers were present in the lesion, the previously recorded ECG or sVCG frequently failed to show the diagnostic signs of infaretion. However, by presenting the depolarization complex in greater detail, the sVCG supplemented the ECG, improving the accuracy of diagnosis of infarction, especially among the smaller, less solid lesions.F OR several years it has been postulated1' and suggested by clinical studies3-that the spatial configuration of the vectoreardiogram would be altered in a predictable fashion by myocardial infarction and that these alterations would have some diagnostic significance. As theoretic considerations of electrocardiographic studies had suggested, the early portions of the QRS sE-loop may be visualized as spatially oriented away from the centroid of the infareted area and toward the centroid of the heart. Previous reports6' 9 have been based almost entirely upon clinical data; only 3 or 4 hearts7' were ever examined at necropsy, usually several weeks to years after recording of the spatial vectoreardiogram. The present investigation was undertaken 2 years ago to study the relation of the electrocardiogram (ECG) and the spatial vectorcardiogram (sVCG) to the clinical

Characteristics of the Frequency Spectrum in the Normal Electrocardiogram and in Subjects Following Myocardial Infarction

“…There is evidence that the mechanism for the production of notching and other high frequency deformities following myocardial infarction is the result of patchy myocardial necrosis with subsequent fibrosis. 9 " 11 We found notching more common in angina pectoris a disease in which Zoll, Wessler, and Blumgart frequently found multiple infarctions. 10 These cause interspersed patches of living and dead myocardium.…”

“…It has been shown that there is additional information to be gained from high-frequency characteristics as revealed by the cathode ray oscillograph and an expanded time scale. 5 Such high frequency characteristics can also be seen in vectorcaridographic loops, 11 provided the amplifiers have adequate high frequency response; however, nondipole components may be sup-*Sec footnote, p. 577. pressed in vectoreardiographic systems.…”

Impulse cardiogram in early diagnosis of left ventricular dysfunction in hypertension.

“…Whereas Scott (1960) reports over-all accuracy to be 85 per cent, Selzer et al (1958) report 70 to 80 per cent, and Rosenfeld et al (1962) 60 to 70 per cent, Burch et al (1958) thought that the electrocardiogram could not be relied upon to indicate chamber enlargement. In the particular context of hypertensive patients, the electrocardiogram as the main test of left ventricular hypertrophy has been found even less satisfactory.…”

Value of vectorcardiogram in diagnosis of posterior and inferior myocardial infarctions.

“…It is well established that the classical pattern of infarction may be absent after myocardial infarction; this is particularly true for the absence of a pathological Q wave (in the inferior leads) after inferior infarction (Burch et al, 1958;Johnson et al, 1959). The electrocardiographic changes may not yet have developed in the early stages after infarction (Short, 1968); subsequently they may diminish so that eventually the electrocardiogram may return completely to normal (Cox, 1967).…”