To elucidate the changes in oxidative metabolism in hibernating myocardium after coronary revascularization, we performed myocardial single-photon emission computed tomography with a free fatty acid analog, I-123 beta-methyliodophenylpentadecanoic acid (BMIPP), and thallium-201 before and 1 month after percutaneous transluminal coronary angioplasty (PTCA) in 11 patients with angina pectoris caused by single artery stenosis. All patients had improvement in wall motion after PTCA at the region with coronary stenosis; the wall motion abnormality score evaluated by left ventriculography decreased from 5.5+/-0.8 (mean +/- SE) to 2.1+/-0.9, p <0.01) after PTCA. The defect score of I-123 BMIPP images was significantly larger than that of thallium-201 images either before (14+/-1.3 vs 8.9+/-1.1, p <0.01) or 1 month after (7.4+/-1.5 vs 3.7+/-0.8, p <0.01) PTCA. The decrease in the defect score of both images was significant (p <0.01). Changes in the wall motion abnormality score showed a significant correlation with both the change in the defect score of thallium-201 images (r = 0.58, p < 0.01) and that of I-123 BMIPP images (r = 0.75, p <0.01). These results indicate that the metabolism of free fatty acid is impaired in hibernating myocardium, and that improvement in left ventricular function after successful PTCA is strongly associated with the recovery of oxidative metabolism.