The precordial electrocardiogram in high lateral myocardial infarction

Abstract

Six cases of suspected infarction of the basal parts of the lateral wall of the left ventricle are reported. The usual unipolar limb leads and the six standard precordial leads failed to furnish unequivocal evidence of myocardial infarction in these cases. Unipolar leads from points on the anterolateral, lateral, and posterolateral aspects of the upper left thorax supplied electrocardiographic data of greater diagnostic value.The types of lesions differentiated have been classified as high anterolateral, high lateral, and high posterolateral infarcts on the basis of the vertical lines in which the most significant electrocardiographic changes were recorded.The opinion is expressed that in these instances the electrocardiographic changes typical of infarction were most pronounced in leads from the upper left thorax because the infarcted region was more basal and more lateral than is usually the case. It is, however, admitted that rotation of the heart or some other change in the relations of its surfaces to the usual leads may have been responsible for some of the electrocardiographic peculiarities encountered.It is recommended that unipolar leads from the higher levels of the left thorax be taken when the clinical history and Lead I, or Lead VL, both suggest that myocardial infarction has occurred and the standard leads from the left side of the precordium fail to display changes of the kind and magnitude expected.