Myocardial preconditioning in humans.

The exact role of myocardial preconditioning in patients with coronary artery disease is not clear. Preconditioning rapidly develops during coronary angioplasty. Myocardial preconditioning probably plays a role in reducing the myocardial infarct size in patients with preceding angina by direct effect, rendering the myocytes more resistant to ischemic injury, by acceleration of thrombolysis, and probably by the increasing recruitment of collaterals. It is also possible that the higher mortality among diabetic patients on sulfonylureas, and their worse outcome during acute myocardial infarction, are related to blockade of preconditioning [39,40]. Myocardial preconditioning does exist during daily life, explaining the well-known phenomenon of "walk-though angina" and the more common "walk-through ischemia." It is hoped that drugs that mimic or enhance preconditioning will be developed, which will provide powerful myocardial protection.