Myocardial viability: known and unknown.

Abstract

The assessment of myocardial viability has gained a lot of attention over the past few years. Various imaging techniques, mainly nuclear and echocardiographic approaches, have been developed for this purpose. From the existing data, it has become clear that the presence of dysfunctional yet viable myocardium can predict improvement of regional and global left ventricular (LV) function after revascularization. This issue is most relevant in patients with severely depressed LV function, since in these patients revascularization carries a high (peri-)procedural risk on the one hand, but may substantially improve LV function in some patients. Besides the improvement of resting LV function after revascularization, other end-points may also be clinically relevant, including the response during stress, improvement of exercise capacity, the quality of life and the prevention of LV remodeling. These issues have not been studied extensively thusfar. Finally, several retrospective studies have shown the prognostic value of viability assessment; patients with viable but jeopardized myocardium were significantly more prone to experience cardiac events than patients with viability who underwent revascularization. The different aspects of viability assessment (including pathophysiology, available techniques, current implications and unresolved issues) will be addressed in this manuscript.