Identification of Ischemic Area of Left Ventricle by Visualization of 43 K Myocardial Deposition

Abstract

A new method to determine myocardial blood distribution was used to study a patient with a recent large transmural anterior myocardial infarct. The method consisted of injecting ⁴³ potassium into a peripheral arm vein and recording the radioactivity over the chest with a scintillation (Anger) camera. Elimination of noncardiac radioactivity in the analysis of data was accomplished by recording the rapid passage of injected ^99m technetium through the heart. The cardiac deposition of the potassium was visualized by identifying the contour of the heart from the technetium scan. In this patient deposition of ⁴³ potassium was markedly reduced in the septal region of the myocardium. This correlated well with the ischemic area suggested by coronary angiography, which demonstrated proximal occlusion of the left anterior descending coronary artery and absence of obstructive disease in the other coronary arteries. Intracoronary artery injection of ⁴³ K gave confirmation of decreased deposition in the same area. This method should prove helpful in the study of certain clinical problems, such as the evaluation of the patency of coronary artery bypass grafts.