Objective To investigate the myocardial protective effects of cardioplegic solution and reperfusional blood containing 4.6μmol/L
captopril (Cpl) on the canine heart under hypothermic extracorporeal circulation.Methods Sixteen mongrel dogs were randomly divided into control and Cpl groups. In the control group, only modified St. Thomas cardioplegia was used, and in the Cpl group, St. Thomas cardioplegic solution and reperfusional blood containing 4.6μmol/L Cpl were used. The hemodynamics, concentrations of CK and CK MB in the
coronary sinus blood, and the contents of malonyldialdehyde (MDA) ), K +,Na +,Ca 2+ and water in the myocardium were determined. Results After
ischemia and reperfusion, the recovery percentages of aortic flow, coronary blood flow, and ±dp/dtmax in the Cpl group were significantly higher than those in the control group ( P <0.05 or P <0.01), while the concentrations of CK and CK MB in the coronary sinus blood, and the contents of MDA, Ca 2+ , Na +, and water in the myocardium of the Cpl group were significantly lower than those of the control group ( P <0.01).Conclusion Captopril can protect the myocardium against ischemia and reperfusion injury by ameliorating coronary circulation, scavenging oxygen free radicals and alleviating Ca 2+ overload.