Localization of the site of myocardial scarring in man by high-frequency components.

The increased incidence of high-frequency components (notching) in electrocardiographic (ECG) recordings previously has been related to coronary artery disease, primary myocardial disease, and biventricular enlargement. This study included 130 subjects on whom autopsy permission was obtained, who had one or more sets of high-frequency, orthogonal ECG (XYZ) leads and directwriting standard ECG leads recorded ante mortem. In each instance careful dissection of the heart was performed by two or more of the authors according to fixed protocol. Correlations were made between the site of infarction and the occurrence of notching in specific high-frequency ECG leads. Postero-inferior infarctions tended to express themselves with a predominance of increased notching in the Y lead, while anterior infarction manifested dominantly in the X lead. This was true in intramural as well as transmural lesions. The greatest value of notch recognition in diagnosing and localizing infarction appeared to be in subjects with normal sized hearts, with none of the classic ECG criteria for infarction, but who ultimately proved to have intramural scarring. In these subjects the increased incidence of notching clearly could not be attributed to biventricular enlargement, nor could the ECG diagnosis of infarction be arrived at by conventional criteria.