Objective To be released specifically after myocardial damage. The goal of this study was to measure serum cardiac troponin I levels after open heart surgery in children, and to evaluate relevance between TnTi and perioperative multi-factors. Methods Fifty-seven consecutive pediatric patients undergoing elective correction of congenital heart diseases were divided into group A (TOF, n=31) and group B (VSD, n=26). Blood samples were drawn preoperatively, 5min(T_ 0), 6h(T_ 6), 12h(T_ 12), 24h(T_ 24), 48h(T_ 48), 72h(T_ 72) after removal of aortic cross clamping. Myocardial protection consisted of moderate systemic hypothermia (30℃~32℃), cold crystalloid cardioplegia and topical cooling. Demographic information, cardiac defect, repair procedure, duration of bypass (CPBT), cross-clamping time (CCT), clinical score for cardiac function, electrocardiographic changes and outcomes were recorded. Results Compared with the baseline value, serum concentration of troponin I peaked at T_ 0 (P<0.01), and fell to normal level at T_ 72 (P>0.05). Peak CTnI was 118 and 55 times higher than the baseline value, respectively in group A and group B.There was a positive correlation between peak CTnI and CPBT, CCT (r=0.51; P<0.01), myocardial operative injury after ventriculotomy and muscle resection (r= 0.35, P< 0.01). Also the peak CTnI value was correlated to the clinical score for cardiac function (r=-0.52; P<0.01). 2.3μg/L was a cutoff value which was highly predictive for postoperative recovery and inotropic support. Conclusion Postoperative serum troponin I is a highly specific and sensitive marker for myocardial ischemia and injury; therefore, its measurement may contribute to the assessment of recovery and outcome after open heart surgery. Objective To be released specifically after myocardial damage. The goal of this study was to measure serum cardiac troponin I levels after open heart surgery in children, and to evaluate relevance between TnTi and perioperative multi-factors. Methods Fifty-seven consecutive pediatric patients undergoing elective correction of congenital heart diseases were divided into groups A (TOF, n = 31) and group B (VSD, n = 26). The blood samples were preoperatively 5min (T_0), 6h (T_6), 12h ), 24h (T_24), 48h (T_48), 72h (T_72) after removal of aortic cross clamping. Myocardial protection consisted of moderate systemic hypothermia (30 ℃ ~ 32 ℃), cold crystalloid cardioplegia and topical cooling. , cardiac defect, repair procedure, duration of bypass (CPBT), cross-clamping time (CCT), clinical score for cardiac function, electrocardiographic changes and outcomes were recorded. Results with the baseline value, serum concentration of troponin I peaked at T_ 0 (P <0 .01), and fell to normal level at T_72 (P> 0.05). Peak CTnI was 118 and 55 times higher than the baseline value, respectively in group A and group B. There was a positive correlation between peak CTnI and CPBT, CCT (r = 0.51; P <0.01), myocardial operative injury after ventriculotomy and muscle resection (r = 0.35, P <0.01). The peak CTnI value was correlated to the clinical score for cardiac function <0.01). 2.3 μg / L was a cutoff value which was highly predictive for postoperative recovery and inotropic support. Conclusion Postoperative serum troponin I is a highly specific and sensitive marker for myocardial ischemia and injury; therefore, its measurement may contribute to the assessment of recovery and outcome after open heart surgery.