The Effects Of Esmolol On Myocardial Zymogram And Ultrastructure In 60 Patients Undergoing Off-pump Coronary Bypass Grafting

Objective: To investigate the effects of intravenous infusion of various dosage esmolol on myocardial zymogram and ultrastructure in 60 patients undergoing off-pump coronary bypass grafting(OPCABG) and to get an reasonable administration of esmolol during OPCABG . Methods: Among sixty patients, cardiac function II or III, undergoing elective OPCABG , the previous thirty patients(cardiac function II)were parted in the larger dosage group and then randomly allocated to testing group(E1, n=15)and controlling group(Ci, n=15); Posterior 13 patients(cardiac function II)and other 17 patients(cardiac function III) wereparted in the small dosage group and then randomly allocated to testing group(E2, n=15)and controlling group(C2, n=15) . After placement of Swan-Ganz duct, in E1, E2 groups , we started infusion of esmolol via central veins at the average rate of 40 ~ 50 g-kg-1-min-1and 20 ~30 g-kg-1-min-1 respectively to the end of closing chest; While in controlling groups ,except with no use of esmolol, the other treatments were same as testing groups. Cardiac troponin I, myoglobin and Creatine kinase isoenzyme (CK-MB) were measured at the time of before operation , end of operation and 24 h after operation ,before closing chest five small blocks of tissues of right auricular appendage were collected in each group to be observed under electron microscope .Results: Cardiac troponin I , Integra of myocardial cell mitochondrion in E1 group were smaller than them in C1 group at the time of end of operation and 24 h after operation (p<0.05), myoglobin , CK-MB had no statistic differences in E1 , C1 groups (p>0.05); All the above markers had no statistic differences in E2 -. C2 groups at correspondent time point (p >0.05) .Conclusions: The intravenous infusion of esmolol at the rate of 40~ 50 g-kg-1-min-1 has myocardial protection in the patients with better cardiac function undergoing OPCABG ,while at the rate of 20 ~ 30 g-kg-1-min-1 has no obvious effects on the changes of myocardium zymogram and myocardial ultrastructure .