PURPOSE: The purpose of this study was to evaluate the perioperative myocardial damage in pediatric congenital heart disease with the cardiac specific protein of cardiac troponin I(cTpn-I). METHODS: All 25 pediatric patients who were diagnosed with tetralogy of Fallot or double outlet right ventricle were classified as group A(acyanotic, SaO2 >90%), group B(mildly cyanotic, SaO2 >80-90%) and group C(moderately cyanotic, SaO2 <80%). The control group D was consisted of 10 patients with ventricular septal defects who were operated in the same period. We measured preoperative hemoglobin, preoperative and postoperative(24 and 72 hour) arterial oxygen saturation, cTpn-I and creatine kinase(CK-MB). RESULTS: Total 25 patients were subdivided into 6 of group A, 12 of group B and 7 of group C. The concentrations of preoperative cTpn-I were 0.23+/-0.12 ng/mL in group A, 0.25+/-0.12 ng/mL in group B, 0.26+/-0.13 ng/mL in group C. And the concentrations of cTpn-I in postoperative 24 hour were 10.04+/-5.28 ng/mL in group A, 12.50+/-6.86 ng/mL in group B, 12.55+/-9.90 ng/mL in group C. Which revealed cTpn-I in group C was higher than that of the another less cyanotic groups. In addition, the concentration of cTpn-I of group C in postoperative 72 hour was higher than any other groups. The concentration of cTpn-I in postoperative 72 hour was statistically correlated with that in postoperative 24 hour and preoperative arterial oxygen saturation(P=0.001). CONCLUSION: Preoperative chronic cyanosis can influence on the postoperative concentration of cTpn-I in pediatric cardiac patients, which means impairment on the postoperative myocardial recovery.