From Washington, D.C., at the Experimental Biology 2004 meeting
Though heart tissue starved of oxygen in a heart attack for more than a few minutes typically begins to die, it doesn't always succumb—especially if the tissue has recently sustained a few short bouts of oxygen deprivation. Such a situation might ensue if an artery to the area had temporarily shut down, as often occurs just before a bona fide heart attack. Something about the deprivation episodes elicits chemical changes that cause cells "to autoprotect," explains Steven Jones of the Johns Hopkins Medical Institutions in Baltimore.
Physicians refer to this process as ischemic preconditioning.