Mild hypothermia decreases arrhythmia susceptibility in a canine model of global myocardial ischemia*

• DOI: 10.1097/ccm.0b013e31825fd39d
• Publication Date: 2012-08-13T19:04:14Z
• Authors: Joseph S. Piktel; David S. Rosenbaum; Lance D. Wilson
• Keywords: Male; Myocardial Ischemia; Arrhythmias, Cardiac; Myocardial Reperfusion; United States; Voltage-Sensitive Dye Imaging; 3. Good health; 03 medical and health sciences; Dogs; 0302 clinical medicine; Hypothermia, Induced; Models, Animal; Animals

Although the majority of sudden cardiac arrests occur in patients with ischemic heart disease, effect therapeutic hypothermia on arrhythmia susceptibility during acute global ischemia is not well understood. While both and severe are arrhythmogenic, undergoing do have an increase arrhythmias, despite fact that most arrest setting ischemia. We hypothesized mild induced prior to myocardial reperfusion will a beneficial ischemia-related substrates.We developed model canine wedge preparation study transmural electrophysiologic effects at different temperatures.Animal study.Male mongrel dogs.Canine left ventricle preparations 1) control (36°C) or 2) hypothermia, simulate temperatures used (32°C), were subjected 15 mins no-flow subsequently reperfused.Optical action potentials recorded spanning wall ventricle. Action potential duration for epicardial, mid-myocardial, epicardial cells was measured. Transmural dispersion repolarization conduction velocity measured baseline, ischemia, reperfusion. No difference seen baseline between groups. Conduction decreased from 0.46 ± 0.02 m/sec 0.23 0.07 m/sec, increased 30 5 msecs 57 4 group Mild attenuated ischemia-induced slowing (decreasing 0.44 0.35 0.03 m/sec; p = .019) (25 3 37 7 msecs; .037). Epicardial block observed six seven group, but no (0/6).Mild repolarization, slowing, block, which known mechanisms arrhythmogenesis These data suggest may decrease