STUNNED AND HIBERNATING MYOCARDIUM

Myocardium that is not functioning may be dead (infarct or scar), viable but stunned (postischemic ventricular dysfunction), viable but hibernating (chronic low flow state), or acutely ischemic. Stunned myocardium has clearly been documented (a) in experimental studies of brief coronary artery occlusion followed by reperfusion, and (b) in myocardial infarct models in which early reperfusion salvages viable tissue. Recent clinical studies have confirmed the existence of stunned myocardium in humans. Evidence supporting the concept of hibernating myocardium comes from clinical studies in which patients with chronic low flow ischemia exhibit improvement in left ventricular function (sometimes immediately) following revascularization.