Myocardial hypothermia: A potential therapeutic technique for acute regional myocardial ischemia

Cardioprotection by Mild Hypothermia. The importance of temperature in the development of necrosis after myocardial ischemia in the beating heart is b ecoming apparent. Recent studies have shown that the proportion of the isch emic risk zone that becomes necrotic is directly correlated with temperatur e. This fact suggests the potential therapeutic benefits of reducing myocar dial temperature after coronary artery occlusion, We have shown in a number of experimental protocols in the rabbit model of myocardial infarction tha t topical regional hypothermia reduces infarct size even when instituted af ter coronary artery occlusion, The reduction in myocardial temperature requ ired to obtain this benefit is modest (30 degrees C to 34 degrees C). Topic al regional hypothermia allows targeted cooling of a zone of the heart, Myo cardial cooling can also be achieved by perfusing the pericardial sac with a chilled fluid by using a closed-circuit catheter system that does not cau se cardiac tamponade, This technique also protects myocardium during ischem ia, Myocardial hypothermia might be a useful technique to limit ischemic da mage during infarction or as adjunctive therapy during minimally invasive c ardiac surgery.