Objective:To observe the protective effects of electroacupuncture on patients undergoing cardiac surgey. Methods: Forty patients with atrial septal defect (ASD) were randomly allocated to 3 groups: acupuncture anesthesia (AA) group (n=12),acupuncture combined with general anesthesia (ACGA) group (n=12), and general anesthesia (GA) group (n=16). Medicines used before operation were phenobarbital sodium (100 mg),pethidine (50 mg),Scopolamine (0.3 mg) in all three groups. Patients of group AA received acupuncture for 15 min before operation. Bilateral Neiguan (PC 6),Lieque (LU 7) and Yunmen (LU 2) were employed. After insertion,the needles were connected with an acupuncture anesthesia apparatus for stimulating the acupoints with electrical impulse 3~4 Hz in frequency,0.5~1 mA in strength and 20~30 min of duration. The stimulation was stopped after heparinization during extracorporeal circulation and continued after neutralization with protaminase. Patients in GA group were induced with dazepam 0.1 mg/kg,vecuronium 0.25 mg/kg,etomidate 0.2 mg/kg and fentanyl 5 μg/kg, and anesthesia was maintained by continuous inhale of isoflurane and intermittent injection of fentany and vecuronium. Patients of ACGA and GA groups were treated with the same methods except for electroacupuncture stimulation in the former group. Hemodynamics parameters including heart rate (HR), mean arterial pressure (MAP),cardiac output (CO),cardiac index (CI),stroke volume (SV),SVR were recorded before and after anesthetic induction,making incision,before performing bypass,stop bypass,30 min after bypass and after operation. Superoxide dismutase(SOD),malonyldialdehyde (MDA),creatine phosphokinase isoenzyme (CPKI) extracted from blood samples of internal jugular vein were analysed before bypass,cease of bypass and 1 hour after bypass. Myocardial samples of right auricle were taken for detecting the expression of heat shock protein (HSP 70 ) mRNA at the time of pre bypass,cease of bypass and 1 hour after bypass. Results: CI,MAP and SV of AA gro