Potassium chloride K 43 is a recently introduced radiopharmaceutical for myocardial imaging. Following intravenous injection, it is taken up by the functioning myocardial cell mass, revealing areas of ischemia, infarction, and fibrosis as regional defects on the myocardial scan. Studies following exercise have shown scan defects not present at rest, thus identifying ischemic myocardial regions.
In 12 patients undergoing operation for coronary artery disease, myocardial scans were obtained at rest or after exercise during the preoperative phase, and compared with the results obtained from coronary cineangiography. Postoperative studies were done within one to 26 days after coronary bypass surgery. Those with an abnormal resting preoperative myocardial scan appear to be a high-risk group.
Myocardial scanning with potassium chloride K 43 is a promising method of evaluating coronary bypass patients. It does not require cardiac catheterization, can be performed as an outpatient procedure, and should prove of value in follow-up studies.