Global and regional myocardial metabolism before and after successful aortocoronary artery bypass surgery
Disabling angina remains the major indication for direct myocardial revascularization by aortocoronary artery bypass surgery in patients with obstructive coronary artery disease. Symptomatic relief of angina following surgery occurs in a vast majority of patients. However, evaluation of the efficacy of any therapy for angina, medical or surgical, based on subjective improvement alone is not only difficult, but may also be deceptive. Angina threshold may be reliably determined by atrial pacing stress which has been employed for the objective assessment of the results of therapy of angina. In order to evaluate changes in angina threshold and global myocardial metabolism, atrial pacing stress was applied before and after surgery in a group of patients with obstructive coronary artery disease. Eighteen patients were studied in an identical fashion before and 2 weeks to 6 months after their successful aortocoronary bypass surgery. All 18 patients developed typical angina during preoperative atrial pacing stress. All patients were men and their ages ranged from 44 to 62 years. The duration of angina varied from 1 week to 14 months before surgery. Six patients had historical and electrocardiographic evidence of old myocardial infarction (three anterior, two inferior, one combined anterior and inferior). Preoperative selective coronary arteriography demonstrated significant obstructive lesions involving left anterior descending coronary artery, left circumflex, and right coronary arteries in the remaining three patients. Six patients had triple, eight had double, two had quadruple, and two had single aorto-LAD saphenous vein grafts. No patient had isolated right coronary artery graft. Forty-three of the . . .