ABSTRACT

Despite significant advances in cardiological diagnosis and treatment, heart failure is still an important cause of mortality and morbidity throughout the world. Noninvasive imaging techniques (echocardiography, magnetic resonance imaging, nuclear imaging, etc.) provide information about the cardiovascular anatomy and function underlying the pathophysiology of heart failure. Viable myocardium is defined by the continuity of cellular metabolic and contractile functions. There are two main reasons for left ventricular systolic dysfunction due to coronary artery disease. The first one is the death of myocytes and the replacement of myocardial muscle tissue by fibrosis tissue after myocardial infarction; this is a process that is irreversible even if revascularization is performed. Secondly-despite the chronic contraction disorder in myocardium, the viability of myocytes is maintained. Myocardial hibernation is the condition in which the myocardium survives, but the function of contraction is impaired. As myocardial viability is preserved in hibernation, the contraction function returns after revascularization. Coronary revascularization can improve left ventricular function, heart failure symptoms, and cardiovascular outcomes in patients with myocardial viability. For this reason, it is important to determine the presence of viable myocardium and functional recovery after revascularization. A lot of imaging modalities are used to characterize the different parameters of cardiac function. This review is intended to reflect the physiological basis of the myocardial viability, to discuss imaging tests that characterize myocardial viability, and to summarize current status of use of these tests in clinical practice.