Baseline heart rate variability in children and adolescents with vasovagal syncope / 소아과

PURPOSE: This study aimed to evaluate the autonomic imbalance in syncope by comparing the baseline heart rate variability (HRV) between healthy children and those with vasovagal syncope. METHODS: To characterize the autonomic profile in children experiencing vasovagal syncope, we evaluated the HRV of 23 patients aged 7-18 years and 20 healthy children. These children were divided into preadolescent (<12 years) and adolescent groups. The following time-domain indices were calculated: root mean square of the successive differences (RMSSD); standard deviation of all average R-R intervals (SDNN); and frequency domain indices including high frequency (HF), low frequency (LF), normalized high frequency, normalized low frequency, and low frequency to high frequency ratio (LF/HF). RESULTS: HRV values were significantly different between healthy children and those with syncope. Student t test indicated significantly higher SNDD values (60.46 ms vs. 37.42 ms, P=0.003) and RMSSD (57.90 ms vs. 26.92 ms, P=0.000) in the patient group than in the control group. In the patient group, RMSSD (80.41 ms vs. 45.89 ms, P=0.015) and normalized HF (61.18 ms vs. 43.19 ms, P=0.022) were significantly higher in adolescents, whereas normalized LF (38.81 ms vs. 56.76 ms, P=0.022) and LF/HF ratio (0.76 vs. 1.89, P=0.041) were significantly lower in adolescents. In contrast, the control group did not have significant differences in HRV values between adolescents and preadolescents. CONCLUSION: The results of this study indicated that children with syncope had a decreased sympathetic tone and increased vagal tone compared to healthy children. Additionally, more severe autonomic imbalances possibly occur in adolescents than in preadolescents.

Risk Factors of Catheter-related Bloodstream Infection Due to Methicillin-resistant Staphylococcus aureus in Very Low Birth Weight Infants

PURPOSE: The incidence of methicillin-resistant Staphylococcus aureus (MRSA) infection has increased in children and in neonates, and is particularly associated with frequent use of central venous catheter in very low birth weight (VLBW) infants. It is known that the morbidity and mortality of MRSA infection are low in neonates, as compared with adults. The objective of this study was to examine the difference in clinical characteristics between VLBW infants that survived and those that did not, a catheter-related bloodstream infection (CRBSI) of MRSA. METHODS: Thirty-four VLBW infants had laboratory-confirmed bloodstream infection with S. aureus. We examined the incidence, mortality and morbidity of CRBSI, and predictive factors associated with mortality. RESULTS: Twenty-six infants had same pathogen (24 MRSA, 2 Methicillin-sensitive Staphylococcus aureus) in the blood and in the catheter tip. Eight infants (25.8%) died in the CRBSI and they all had MRSA blood infections. Sex ratio, gestational age, duration between blood collection and identification of pathogens, and WBC and platelet count were not significantly different between patients that died from and patients that survived CRBSI of MRSA. C-reactive protein (CRP) was significantly higher in VLBW infants that died. Mean age of onset and hospital day was earlier (9.1+/-6.6 vs. 26.9+/-20.2; P=0.005) and shorter for patients that died (10.1+/-7.0 vs. 73.0+/-32.4; P=0.000). Two survivors had complications of pyogenic arthritis of the lower extremities and soft tissue infection, respectively. CONCLUSION: Mortality of CRBSI was likely to be high in VLBW infants and might be anticipated by CRP and early onset of disease.

Correlations of cord blood Ghrelin and leptin concentrations with anthropometry of appropriate for gestational age newborns / 소아과

PURPOSE: Ghrelin stimulates the secretion of growth hormone and other pituitary hormones, and has orexigenic effects. It may have a physiologic role in fetal and neonatal growth. Leptin secreted by the adipocytes reflects fat mass in infants as well as adults. The aim of this study was to evaluate the relation of cord blood ghrelin and leptin levels to body weight(BW), body mass index(BMI), insulin-like growth factor-I(IGF-I) and insulin-like growth factor binding protein-3(IGFBP-3) levels in appropriate for gestational age(AGA) newborns. METHODS: Sixty healthy AGA newborns(31 males and 29 females, gestational age[GA] 34-42 weeks) were included in this study, whose BW and BMI were measured at delivery. Umbilical cord venous blood samples were withdrawn, and ghrelin and leptin were measured by radioimmunoassay. Cord blood IGF-I and IGFBP-3 were determined by immunoradiometric assay. RESULTS: The mean levels of ghrelin were inversely correlated with BW(r=-0.29, P<0.05) and GA (r=-0.28, P<0.05), but were not affected by gender. The mean levels of leptin levels showed positive correlation with BW(r=0.44, P<0.01), GA(r=0.36, P<0.01), and BMI(r=0.28, P<0.05). The leptin levels of females were higher than those of males. There was no gender difference in leptin levels in neonates under GA 37 weeks. However, the leptin levels of females were higher than those of males (P<0.01) in newborns with GA 37 weeks or over. There was no correlation between ghrelin and leptin levels. Ghrelin and leptin levels showed no relations to cord blood IGF-I and IGFBP-3 levels. CONCLUSION: These data suggest that cord blood ghrelin may have an inverse correlation with BW in AGA newborns, and leptin levels are positively correlated with BW and fat mass. Further study of ghrelin concentrations in cord blood is necessary to elucidate the physiological and pathological roles of ghrelin during the fetal and neonatal periods.