Early postoperative assessment of coronary artery bypass surgery using nuclear left ventriculography and atrial pacing.

Nuclear ventriculography (MUGA) was performed in 22 patients at rest and during the stress of right atrial pacing 6 to 8 days after coronary artery bypass surgery. In 7 patients the MUGA-atrial pacing test was positive for ischemia with chest pain, electrocardiographic ST depression and/or a decrease in global left ventricular ejection fraction of greater than 10%. All 7 patients subsequently developed angina pectoris with a positive treadmill test (performed at a median time of 14 months after operation). In 15 patients, the early postoperative MUGA-atrial pacing test was negative. In this group, 3 patients subsequently developed angina pectoris with a positive treadmill test in one. The sensitivity of the 'one week' early postoperative MUGA-atrial pacing in the identification of patients with residual myocardial ischemia was high (88% for positive GXT, p less than 0.0001; 70% for chest pain, p less than 0.005) with 100% specificity. The early postoperative MUGA scan was also useful in predicting later shortness of breath on exertion and there was a significant correlation between the early resting ejection fraction and the exercise capacity of the patient subsequently. The information obtained from an early postoperative MUGA-atrial pacing study may have far-reaching and important practical application in selecting patients for early recatheterization, possible fibrinolysis and/or possible cardiac reoperation.