Is there a need to assess myocardial viability in patients presenting with heart failure?

Abstract

Cardiac MRI is unique amongst the cardiac imaging modalities in its ability to directly image myocardial fibrosis using late gadolinium enhancement techniques. The ability to identify not only the presence of fibrosis but also its pattern of distribution within the myocardium can aid in distinguishing between ischemic and nonischemic causes of left ventricular dysfunction, as well as provide valuable prognostic information for patients with various etiologies of heart failure. Amongst patients with ischemic cardiomyopathy, the Surgical Treatment for Ischemic Heart Failure (STICH) trial was attempted to assess the value of coronary artery bypass surgery. Although the early results were disappointing as to the overall utility of surgical revascularization, the recently published 10-year follow-up now demonstrates improved survival amongst patients undergoing surgical revascularization when compared with medical therapy alone. Although a substudy of STICH failed to demonstrate utility of preprocedural viability assessment with dobutamine echocardiography or single-photon-emission computed tomography, other studies support the identification of myocardial fibrosis as carrying important prognostic information. The ongoing development of new techniques, particularly T1 mapping of extracellular volume fraction, holds promise for the future as early studies suggest complementary prognostic value and perhaps the ability to avoid contrast administration. Cardiac MRI use for viability assessment demonstrates important utility amongst patients with heart failure, regardless of its cause.