Myocardial preconditioning as the heart's self-protecting response against the consequences of ischaemia

An initial ischaemic stimulus preconditions the myocardium and increases the heart's tolerance for further damage. Myocardial preconditioning reduces infarct size, decreases arrhythmia and degree of myocardial stunning through various mechanisms. The initial preconditioning occlusion must be between one and five minutes in duration and the period of reperfusion must exceed one minute. Proposed mechanisms of preconditioning include the release of adenosine and endogenous cardioprotective substances such as prostacyclin, nitric oxide and bradykinins.