Why is the reenergization of myocardial cells harmful after prolonged ischemia?
About two decades ago, Hearse and coworkers [4] demonstrated that, in the oxygen depleted and reoxygenated myocardium, severe myocardial injury, characterized by myofibrillar hypercontracture and sarcolemmal disruption, may develop with the onset of reoxygenation. It has been demonstrated by Ganote and coworkers [5] that this injury is due to the resumption of energy production upon reoxygenation. This phenomenon of severe cell injury immediately provoked by reenergization has been termed “oxygen paradox.” It has remained an open question for a long time whether the oxygen paradox represents genuine “reoxygenation injury” or just a dramatic manifestation of injury that has already developed during the oxygen depletion period. The presence of contraction bands in infarcted myocardium is a histological indicator of oxygen paradox injury in ischemic-reperfused myocardium. Histologic analysis clearly demonstrates that when reperfusion is performed early enough to produce some myocardial sa
