PURPOSE: To determine the prevalence of viable myocardium in patients with ischemic cardiomyopathy and, to evaluate the value of three-dimensional (3-D) fusion imaging of myocardial scintigraphic and angiographic data to assign coronary artery lesions to the corresponding viable and nonviable myocardial territory. PROCEDURES: In 105 patients, the combination of perfusion and metabolic imaging with (201)thallium ((201)TI) single-photon emission computed tomography (SPECT) and 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) determined viability in dysfunctional myocardium. In addition, the value of 3-D scintigraphic fusion imaging was assessed in these patients. RESULTS: Based on the presence of viable dysfunctional myocardium, 54% of patients with ischemic cardiomyopathy may be considered for coronary revascularization. In 31 of 105 patients, the 3-D fusion imaging was estimated to be helpful in the diagnostic and interpretative process. CONCLUSION: In patients with end-stage coronary artery disease scintigraphic imaging is most important in the decision-making process. Three-dimensional fusion imaging may add important information in approximately 30% of these patients.