About 5.3 million people in the United States -suffer from heart failure, the cause of which in many patients is atherosclerotic coronary artery disease. The clinical prognosis in patients with ischemic heart failure is worse than in those with a nonischemic etiology, but the former can potentially be improved with revascularization. Integrated positron emission tomography/computed tomography (PET/CT) scanners provide a unique opportunity for determining the cause of heart failure by integrating anatomic and functional imaging of coronary circulation and heart anatomy in a single study. Several studies have shown that a combined approach of coronary CT angiography and PET-assisted myocardial perfusion imaging can accurately -evaluate coronary artery disease as the underlying cause of chronic and new-onset heart failure. PET viability testing can reveal the amount of functional myocardium and help in selecting a therapeutic strategy in patients with heart failure. Even though properly conducted prospective randomized trials are still lacking, PET/CT may become the method of choice for initial evaluation and management of patients with heart failure.