Abstract 158: Transient Hypothermia During the Acute Phase of Myocardial Infarction Dramatically Reduces Scar Size, Prevents Left Ventricular Dilation and Remodeling, and Preserves Cardiac Function

Background: While hypothermia (H) induced by the non-invasive ThermoSuit apparatus (convective-immersion cooling) acutely reduced myocardial infarct (MI) size in our experimental models, the long term effects of transient hypothermia on MI scar size, left ventricular (LV) remodeling, and LV function are largely unknown. Therefore we assessed the long term effects of transient H in our chronic rat MI model. Methods: Rats were randomized to normothermic (N) or H groups (n=14 in each group). Rats were subjected to 30 minutes coronary artery occlusion and reperfusion for 6 weeks. For H therapy, rats were placed into the ThermoSuit apparatus at 2 minutes after the onset of coronary artery occlusion, and were taken out of the apparatus when the core body temperature reached 32°C (in ~8 minutes) and were then allowed to rewarm. Results: After 6 weeks of recovery, rats treated with H demonstrated markedly reduced scar size (expressed as % of left ventricular area H, 9 ± 2%; N, 27 ± 3%; p < 0.001), and thicker ant...