Oxygen free radicals and myocardial reperfusion injury.

Diseases involving tissue reperfusion following ischemia are gaining significance in emergency medicine. The significance of reperfusion injury and the probable role of oxygen-derived free radicals has been described in many tissues, particularly the heart. During myocardial reperfusion a burst of oxygen-derived free radicals overwhelms normal cellular defenses. These radicals may have several detrimental effects. They can oxidize lipids, leading to membrane dysfunction. They can also alter nucleic and other proteins. Cellular dysfunction and death may ensue. Prevention of oxygen-derived free radical injury appears possible and may be feasible for several disease processes, including myocardial reperfusion after infarction.