Noninvasive assessment of left ventricular viability: Did we underestimatethe potential of stress Echocardiography

The presence of myocardial viability within a noncontracting infarct zone i s an important determinant for left ventricular function recovery after int erventional coronary revascularization. However, this holds true only for h ibernating myocardium in which a perfusion-limiting infarct-associated coro nary artery stenosis persists tin contrast to stunning with postischemic re perfusion and spontaneous recovery). Echocardiographic techniques are highl y valuable in identifying hibernation, especially in conjunction with dobut amine titration. Low doses may detect the inotropic reserve by significant enhancement of segmental wall-motion abnormalities while high doses may sur pass the ischemic threshold and the wall motion deteriorates (biphasic resp onse). Dobutamine echocardiography should not be performed too early after the infarct, not only because of security reasons (arrhythmogenic potential ), but also because of higher diagnostic accuracy (resolution of stunning w ithin the first several days postmyocardial infarction thereby separating v iable myocardium attributed to hibernation. According to the Task Forces on Clinical Application of Echocardiography by the American Heart Association in cooperation with the American College of Cardiology, dobutamine echocar diography is officially recommended for the purpose of clinical decision ma king in respect to revascularization therapies (whether during the subacute infarct period or, especially, in chronic left ventricular dysfunction due to coronary artery disease).