Substantial progress has been made in understanding the pathophysiology of regional and global left ventricular (LV) dysfunction and the states of hibernation and stunning in patients with heart failure. The clinical literature on the use of noninvasive imaging to assess myocardial viability has evolved from predicting improvement in regional LV function to predicting patient-related outcomes, including heart failure symptom improvement and survival after revascularization. A substantial body of observational cohort data demonstrates that mortality risk is high in patients with coronary artery disease and LV dysfunction who have substantial viable myocardium, and that risk is reduced by revascularization. Thus, noninvasive imaging of myocardial ischemia and viability can provide important prognostic information in patients with heart failure and LV dysfunction, and provide a signal of the potential benefit of revascularization.