Objective To investigate effects and mechanisms of dexmedetomidine preconditioning on ischemia-reperfusion arrhythmia in rats.Methods From March to June 2015 in Basic Mesical College of Wuhan University,30 rats were divided into sham operation group(SO group),ischemia-reperfusion group(I/R group) and dexmedetomidine preconditioning group(DEX group),10 rats each group.Firstly,the coronary artery was ligated for 30 rain to cause myocardial ischemia,and then the ligature was loosened for 120 min to give the my...