Preconditioning: ischemia-induced tolerance to lethal injury

Repetition of one or several brief episodes of ischemia renders the myocardium more resistant to a subsequent sustained coronary artery occlusion. The hallmark of tills phenomenon, termed preconditioning, is infarct size limitation. Its mechanism is unclear but seems to involve the release of several mediators, including adenosine, norepinephrine, bradykinin, endothelin-1 and the activation of protein kinase C. This cardioprotection is not limited to the heart but can affect many other organs. Recent evidence suggests that it may also apply to the human heart, especially during cardiac surgery, coronary angioplasty or in the clinical settings of pre-infarction angina.