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Frequency of Elevations in Markers of Cardiomyocyte Damage in Otherwise Healthy Newborns

https://doi.org/10.1016/j.amjcard.2008.04.057Get rights and content

Myocardial damage in infancy is a risk factor for eventual cardiac disease. Given that myocardial stress is greatest during the perinatal period and that the neonatal period is when most pediatric heart failure occurs, the aim of this study was to determine whether even otherwise healthy neonates might have subclinical myocardial damage and, if so, what characteristics might identify them. Umbilical cord and neonatal serum samples from 32 normal neonates were assayed for biomarkers of myocardial injury. No neonate had clinical evidence of cardiac or other abnormalities. Serum cardiac troponin T was elevated in 19 of 25 cords (76%) and in 16 of 17 neonates (94%); levels indicating myocardial infarction (≥0.2 ng/ml) were found in 2 patients (1 umbilical cord and 1 neonatal sample). Creatine kinase-MB was elevated in 6 of 16 cords (38%) and in 8 of 15 neonates (53%). Cardiac troponin I was elevated in 11% and 17% of samples, myoglobin in 4% and 17%, and high-sensitivity C-reactive protein in 9% and 40%. Measures of myocardial injury were associated with longer hospitalization (r = 0.50, p = 0.04), non-Caucasian race (p = 0.012), lower birth weights (p = 0.014), positive maternal cervical cultures (r = 0.41, p = 0.046), and elevated high-sensitivity C-reactive protein (r = 0.66, p = 0.005). In conclusion, clinically occult myocardial injury appears to occur in some healthy newborns, although whether it is pathologic or not remains to be determined.

Section snippets

Methods

The institutional review board of the University of Rochester Medical Center approved this study. Parents gave written informed consent. We enrolled a convenience sample of healthy newborns at the University of Rochester Medical Center from 1999 to 2002. Umbilical cord and neonatal serum samples were obtained as close to 48 hours of age as possible and stored at −70°C. We abstracted perinatal data from maternal and neonatal medical records (Table 1, Table 2).

Stored sera samples were assayed at

Results

We enrolled 32 clinically healthy, full-term neonates whose sizes was mostly (91%) appropriate for gestational age and who had normal lengths of hospitalization (Table 1, Table 2). None had known or suspected cardiac disease, symptoms, or medications; maternal inflammatory events; severe congenital anomalies; reduced intravascular volume; renal dysfunction; postnatal infections; treatment with cardiotoxic medications; or glucocorticoid or thyroid supplementation. There was insufficient blood

Discussion

The proportion of neonates with elevated cTnT levels was higher than that in ill infants, children, and adolescents and in healthy adults in the published research,2, 9 suggesting that myocardial injury, although clinically occult, is common in this young age group. This conclusion is supported by elevations in the other markers of cardiomyocyte injury. It remains unclear whether these increased levels represent normal neonatal values associated with physiologic myocardial remodeling, occult

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