Assessment of Myocardial Viability

Abstract

The primary goal of myocardial viability assessment in ischemic cardiomyopathy is to predict the likelihood of contractile recovery of dysfunctional myocardium following medical therapy and revascularization. Myocardial viability is estimated by probing a variety of biologic properties of a ‘living myocyte’, typically by cardiac imaging modalities-echocardiography, nuclear (SPECT & PET), and cardiac magnetic resonance-each with its own merits and limitations. While there is still an ongoing debate on the degree of therapeutic value of viability assessment, current guidelines acknowledge its prognostic and therapeutic utility in clinical practice. Viability status may not always be an all or none binary phenomenon but can be a wide spectrum from early hibernating to terminal pre-scar stages of the myocardium. As a result, estimating myocardial viability and predicting the revascularization benefits in severe ischemic cardiomyopathy with adverse remodeling can be a challenging task, at times. The decision to pursue revascularization should be based on the several factors that may determine the success of therapy, including the degree of myocardial ischemia, extent of viable and non-viable myocardium in the territory of the culprit coronary artery, left ventricular volumes, left ventricular ejection fraction, patient’s comorbidities and procedural risk. This chapter provides an overview of assessment of myocardial viability, its therapeutic and prognostic implications as well as management of ischemic cardiomyopathy based on the myocardial viability status.