In a 27-year-old man with Bland-White-Garland syndrome (anomalous origin of the left coronary artery from the pulmonary artery), comparison was made between conventional diagnostic techniques and radionuclide imaging for selection of surgical procedure and evaluating the outcome. Dynamic 99mTc imaging exactly located the left coronary artery orifice, which was not seen on angiography, thereby determining the surgical approach, and 123I study revealed that, despite absence of symptoms, the adrenergic activity of the heart was globally diminished, with limited response to revascularization.