Comparison of cardiac troponin I with CK-MB in the diagnosis of myocardial injury in children

Objective To determine the impacts of various pathological changes on serum cardiac troponin I (cTnI) levels and creatine kinase MB isoenzyme (CK-MB) activity and to compare the diagnostic values of cTnI with that of CK-MB. Methods Serum cTnI levels and CK-MB activity were measured in four groups of children. Group A included 54 healthy children as control. Group B included 53 pediatric patients without cardiac diseases. Group C included 12 pediatric patients with stable congenital heart diseases. Group D included 14 pediatric patients with acute myocarditis. Results The cTnI levels were all less than 0.25 μg/mL in group A and there were no significant differences among the subgroups of different ages. CK-MB was increased in one patient (1.9%). cTnI did not differ significantly among groups A, B, and C. One patient (1.9%) had elevated cTnI and nine patients (16.9%) had higher CK-MB in group B. No increase in cTnI occurred in group C whereas CK-MB was elevated in one patient (8.3%). cTnI in group D was increased in 11 patients and its mean value was markedly higher than that in group A (P 0.01). Conclusion cTnI can be used to diagnose myocardial injury in children with a high specificity and sensitivity. No elevation in cTnI occurred in the children who have no cardiovascular diseases. CK-MB activity, however, can be affected by other disorders besides cardiovascular diseases.