Myocardial viability and imaging in the failing heart

Patients with ischemic cardiomyopathy experience impaired left ventricular function, a major contributor to the morbidity and mortality related to heart failure. Yet left ventricular dysfunction in many patients with myocardial stunning or hibernation may be reversible. When viable myocardium is present, coronary revascularization can lead to functional recovery, improvement in symptoms, and prognosis. Knowing which patients will benefit from revascularization is, obviously, clinically important. Clinicians have a range of diagnostic testing options that identify the presence or absence of viable myocardium. This chapter describes the available viability testing options in detail, including their benefits and limitations. These testing options include echocardiography, dobutamine stress echocardiography, single-photon emission computed tomography (SPECT), positron emission tomography (PET), cardiac computed tomography (CCT) imaging, and the current gold standard of delayed-enhancement cardiac magnetic resonance imaging (DE-CMR). The value of myocardial viability testing in predicting outcomes after revascularization has also been evaluated in many small single-center studies-and looks promising-but needs continued research.