Rest and Exercise Myocardial Imaging in the Assessment of the Postoperative Cardiac Patient

Abstract

An obvious application of the rest-and-exercise myocardial-imaging approach would be the study of patients having undergone aortocoronary bypass surgery. The recent introduction of this surgical modality has significantly altered the therapeutic approach toward patients with coronary heart disease. Coronary revascularization procedures are now being performed in patients representing the entire spectrum of coronary disease, ranging from the situation of minimally symptomatic angina pectoris to cardiogenic shock. However, postoperative subjective improvement may not, in all cases, be due to increased myocardial perfusion. Reduction or elimination of symptoms in the individual patient may also result from perioperative infarction of ischemic muscle, partial denervation, or placebo effect. On the other hand, symptoms may persist in the presence of entirely patent bypass grafts. Dispute currently rages as to whether the procedure, even in the face of symptomatic improvement, will have a long-term effect on patient survival and prognosis. Definitive objective evaluation of the postoperative patient has required cardiac catheterization and contrast angiography, which by their very nature are limited in terms of sequential study. For this reason, a noninvasive means of evaluating graft patency and myocardial viability would have definite clinical and investigative value. To this end, we have applied rest and exercise ⁴³K and ⁸¹Rb myocardial imaging to the study of the postoperative patient.