Although beneficial in terms of myocardial salvage, reperfusion itself may contribute to additional damage of the myocardium; the damage due to the combined processes is known as "ischemia-reperfusion injury". The pathogenesis of myocardial ischemia-reperfusion injury is a multifactorial process involving the interaction of multiple mechanisms. Numerous studies indicate that there are three pivotal factors in the pathogenesis of ischemia-reperfusion injury: elevated oxidative damage, depressed energy metabolism, and altered calcium homeostasis.