The goal of myocardial viability assessment is to differentiate, prospectively, patients with potentially reversible from irreversible left ventricular dysfunction. Ideally, this information should be used to guide therapeutic decisions for revascularization. Therapeutic interventions that improve non functioning but viable myocardial regions may improve significantly global left ventricular function as well as impact left ventricular dysfunction, in which revascularization entails high perioperative morbidity and mortality. Accurate assessment of myocardial viability may result in more appropriate utilization of resources and enhance efficiency in health care delivery. Myocardial viability can be valorated with perfusion images using dual method or tallium reinjection, isotopic ventriculography, Gated SPECT with dobutamine stress or cardiac metabolism with PET.