CARDIAC TROPONIN-I IN PEDIATRICS - NORMAL VALUES AND POTENTIAL USE INTHE ASSESSMENT OF CARDIAC INJURY

Objective: To establish normal values and determine the impact of cong enital or acquired heart disease on serum cardiac troponin I (cTnI). M ethods: Concentrations of cTnI were measured in two groups of children , Group A represented ambulatory pediatric patients with no apparent c ardiac disease (n = 120) and patients in stable condition with known c ongenital or acquired cardiac abnormalities (n = 96); group B was comp osed of patients admitted to intensive care units with normal echocard iograms (n = 16), with abnormal echocardiograms (n = 36), and those wi th blunt chest trauma who were thought to have cardiac confusions (n = 7), Results: The cTnI concentrations were generally less than 2.0 ng/ ml in group A and frequently below the level of detection for the assa y (1.5 ng/ml). There was no statistical difference between the two out patient subgroups (p = 0.66), Nine intensive care patients had cTnI va lues greater than 2.0 ng/ml. Six of these patients, all with abnormal echocardiograms, had values less than 7.7 ng/ml, All improved and had subsequent normal cTnI concentrations. None of the three remaining pat ients (two with systemic illness (trauma and sepsis) and one with seve re pulmonary hypertension), all with values greater than 8.0 ng/ml, su rvived. Three of the four patients with high likelihood of cardiac con fusion had cTnI concentrations greater than 2.0 ng/ml (including one p atient who died). Conclusions: Cardiac troponin-I values are generally not elevated in children with stable cardiac disease or general pedia tric conditions. In the context of severe acute illness, significant e levation of cTnI may be an indicator of poor outcome. Elevation of cTn I may also have diagnostic value in cases when cardiac confusion is su spected.