Preconditioning: ischemia-induced tolerance to lethal injury

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