The phenomenon of ischemic preconditioning has been recognized as one of the most potent mechanisms to protect against myocardial ischemic injury. In experimental animals and humans, a brief period of ischemia has been shown to protect the heart from more prolonged episodes of ischemia, reducing infarct size, attenuating the incidence, and severity of reperfusion-induced arrhythmias, and preventing endothelial cell dysfunction. Although the exact mechanism of ischemic preconditioning remains obscure, several reports indicate that this phenomenon may be a form of receptor-mediated cardiac protection and that the underlying intracellular signal transduction pathways involve activation of a number of protein kinases, including protein kinase C, and mitochondrial KATP channels. Apoptosis, a genetically programmed form of cell death, has been associated with cardiomyocyte cell loss in a variety of cardiac pathologies, including cardiac failure and those related to ischemia/reperfusion injury. While ischemic preconditioning significantly reduces DNA fragmentation and apoptotic myocyte death associated with ischemia-reperfusion, the potential mechanisms underlying this effect have not been fully clarified. A comprehensive understanding of these mechanisms and application to clinical scenarios will provide new directions in research and translate this information into new treatment approaches for reducing the extent of ischemia/reperfusion injury
