Early Postoperative Assessment of Coronary Artery Bypass Surgery Using Nuclear Left Ventriculography and Atrial Pacing*

Summary

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 > 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 < 0.0001; 70 % for chest pain, p < 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 farreaching and important practical application in selecting patients for early recatheterlzation, possible fibrinolysis and/or possible cardiac reoperation.

Key words

Myocardial revascularization - Angina pectoris - Nuclear angiography - Stress testing