Radionuclide angiography has been increasingly utilized to evaluate left ventricular function in a wide variety of disease states. Comparison with contrast ventriculography has shown that radionuclide angiography is an accurate means of determining global ejection fraction. Moreover, studies have shown that this technique is of particular value in detecting the presence and severity of regional asynergy as, for example, in the delineation of a discrete aneurysm versus global asynergy as the cause of congestive heart failure. The relative ease of repetitive examinations permits evaluation of left ventricular function under different conditions. Thus, radionuclide angiography is being increasingly used as a prognostic and therapeutic guide. In addition, it can be used during an acute intervention--for example, with administration of nitroglycerin to detect reversible asynergy or, as recently demonstrated by several groups, during exercise as a relatively sensitive and specific means to detect coronary heart disease.