Prime causes of rapid cardiomyocyte death during reperfusion

In ischemic-reperfused myocardium, necrosis of cardiomyocytes may develop not only due to the ischemic conditions but also the specific circumstances of reperfusion. The existence of reperfusion injury becomes apparent when modifications of the conditions of reperfusion can prevent cell death otherwise occurring. Three prime causes of rapidly developing reperfusion injury are here discussed, ie, reenergization of cells at increased cytosolic Ca2+ contents, rapid normalization of tissue pH, and rapid normalization of tissue osmolality. All three causes lead to severe mechanical stress of cardiomyocytes which can cause their rapid deterioration. Propagation of cell injury among adjacent cells can cause a spreading of necrosis throughout myocardial tissue. The understanding of these initial causes of rapidly developing lethal reperfusion injury leads to new concepts for specific protection of reperfused myocardium. (C) 1999 by The Society of Thoracic Surgeons.