Abstract: Objective: To investigate the protective effect of propofol on reperfusion arrhythmia and myocardial metabolism in isolated working rat heart.Methods: The healthy male SD rats were randomly divided into two experiment groups.The first experiment group was divided into 4 subgroups(with 10 animals in each subgroup):control group,propofol 10 μmol/L group(P10),50 μmol(P50) group and 100 μmol(P100) group;and the second experiment group(catecholamine depletion group) was divided into 3 subgroups(in with 10 anilmals in each subgroup):saline control group(SC),catecholamine-depleted group(DC) and catecholamine-depleted plus propofol 50 μmol group(DP).The isolated working heart model was used,and coronary outflow was collected for determination of creatine kinase(CK) and catecholamine(epinephrine,norepinephrine and dopamine) concentrations.Severity of arrhythmias was determinated with single ventricular premature beat(VPB),SALVO,ventricular tachycardia(VT) and ventricular fibrillation(VF).Results: Before ischemia,the frequency of the reperfusion arrhythmia was very low,the CK and catecholamine concentrations were not significantly different(P>0.05) among all the subgroups.During reperfusion,the frequency and severity of arrhythmias in subgroups P10,P50,P100,DC and DP were significantly less than that in the control groups(P<0.05);the epinephrine and norepinephrine concentrations in coronary outflow in subgroups P10,P50,P100 were significantly lower than that in control group,and the dopamine concentration were not significantly different in all subgroups;Catecholamine of group DC and DP was not detectable.The CK concentrations of the coronary outflow in subgroups P10,P50,P100 were significantly lower than that in control group.Conclusions: Propofol may markedly protect isolated heart from reperfusion arrhythmia through suppression of catecholamine release following ischemia-reperfusion.