Heart failure is a significant health problem and coronary artery disease is by
far the leading cause. Despite advances in medical and device therapy the prognosis of
patients with ischemic cardiomyopathy remains unfavorable, but revascularization may
further improve the outcome in terms of contractile function, symptomatic relief,
exercise capacity and mortality. Over the years, the presence of myocardial viability
has been considered a significant determinant of the benefit from revascularization and
a variety of noninvasive techniques have been developed to assess viable and nonviable
myocardium in patients with ischemic systolic dysfunction. Viability imaging with 201Tl
and 99mTc-agents SPECT can evaluate perfusion, cell membrane and mitochondria
structural and functional integrity, whereas 18F-FDG PET is used for the assessment of
glucose metabolism in myocytes. Dobutamine stress echocardiography provides
information on the contractile reserve and cardiac magnetic resonance imaging can
delineate the transmural extent of scar. In general nuclear imaging techniques have a
higher sensitivity for the detection of myocardial viability, whereas techniques
evaluating contractile reserve display a lower sensitivity but a higher specificity. This
review focuses primarily on the radionuclide modalities for the assessment of
myocardial viability and discusses the clinical value of viability imaging, including
earlier retrospective work and the more recent prospective data.
Keywords: Coronary artery disease, Heart failure, Left ventricular remodeling,
Myocardial metabolism, Myocardial perfusion, Myocardial viability