Objective To investigate the effect of penehyclidine hydrochioride(PHC)on myocardial NF-κB activity and plasma level of TNF-α during cardiopulmonary bypass(CPB)in patients undergoing heart valve replacement.Methods Forty-five NYHA Ⅱ or Ⅲ patients of both sexes aged 18-64 yr with body mass index 20-22 kg/m~2 undergoing valve replacement under CPB were randomly divided into 3 groups(n = 15 each): control group(group C)and two PHC groups(group P_1,P_2).Group P_1 and P_2 received PHC 0.05 and 0.1 mg/kg respectively at the beginning of operation via central venous line.Myocardial specimens were taken from right auricle before CPB(baseline,T_1)at 30 min after aortic clamping(T_2)and 30 min after aortic unclamping(T3)for determination of NF-κB activity by immuno-histochemistry.Arterial blood samples were taken at T_1,T_2,T3 and4,24 h(T_4,T_5)after aortic unclamping for determination of plasma concentrations of TNF-α and cTnI.Results The myocardial NF-κB activity and plasma concentrations of TNF-α and cTnI were significantly increased during CPB as compared with the baseline values before CPB at T_1 in all 3 groups and were significantly lower in group P_1and P_2 than in group C.Conclusion PHC administered before CPB can protect myocardium from ischemia-reperfusion injury by inhibiting the increase in myocardial NF-κB activity and plasma TNF-α concentration induced by ischemia-reperfusion.