• Cardiac biomarkers in neonatal hypoxic ischaemia.

      Sweetman, D; Armstrong, K; Murphy, J F A; Molloy, E J; Neonatology, National Maternity Hospital, Dublin, Ireland. dsweetman@nmh.ie (2012-04)
      Following a perinatal hypoxic-ischaemic insult, term infants commonly develop cardiovascular dysfunction. Troponin-T, troponin-I and brain natriuretic peptide are sensitive indicators of myocardial compromise. The long-term effects of cardiovascular dysfunction on neurodevelopmental outcome following perinatal hypoxic ischaemia remain controversial. Follow-up studies are warranted to ensure optimal cardiac function in adulthood. CONCLUSION: Cardiac biomarkers may improve the diagnosis of myocardial injury, help guide management, estimate mortality risk and may also aid in longterm neurodevelopmental outcome prediction following neonatal hypoxic-ischaemia.
    • Tissue Doppler Imaging Quantifies Early Changes in Preterm Myocardium

      Armstrong, K; Molloy, E; Franklin, O (Archives of Disease in Childhood, 2012-10)
      Abstract Introduction Haemodynamic changes occurring during the fetal – neonatal transition may impact on global myocardial function in the first week of life. Tissue Doppler imaging (TDI) offers a novel technique to measure changes in systolic and diastolic function in neonates. Aims To use TDI to assess myocardial function in preterm infants compared to gold standard measures. Methods Preterm infants < 32 weeks gestation were recruited. Echocardiography was carried out by a single observer (KA) using the GE Vivid I, on Day 1, 3–4 and Day 7. Clinical parameters were recorded at time of echocardiogram. Standard M mode echocardiography was used to determine shortening and ejection fraction. Myocardial velocities were obtained using a pulsed wave doppler sample from the lateral mitral/tricuspid annuli and intraventricular septum from an apical four chamber view. Peak systolic (S’), early diastolic (E’) and late diastolic (A’) velocities were recorded. Results 140 echocardiograms were performed on 60 neonates with structurally normal hearts. Gestational age range-23+ 6–31+ 6 weeks. There was a significant increase in heart rate (p=0.002)and systolic blood pressure over the 1st week. (p=0.001). There was an increase in myocardial velocities across all measurements, with right ventricular early systolic and late diastolic velocities increasing significantly (p<0.002). There was a significant increase in the left ventricle late diastolic velocities (p=0.036). There was no significant difference in shortening/ejection fraction over the first week. Conclusion TDI offers a reliable measure of myocardial velocities over the first week. Current gold standard measures shortening/ejection fraction showed no significant change in myocardial contractility however TDI demonstrated significant changes in both RV and LV systolic and diastolic velocities.
    • Vitamin D Levels and myocardial function in preterm infants

      Armstrong, K; Onwunmeme, C; Franklin, O; Molloy, E (Archives of Disease in Childhood, 2013-08-20)
      Bakground Low Vitamin D levels have been linked to cardiac failure in the adults and children. Tissue Doppler Imaging (TDI) is evolving as a superior measure of subtle changes in myocardial contractility in preterm infants. We aimed to correlate Vitamin D levels at birth with TDI measures of systolic and diastolic function. Methods Preterm infants < 32 weeks gestation were recruited. Vitamin D levels were measured at birth and echocardiography was carried out on Day 1. TDI myocardial velocities were recorded using a pulsed wave doppler sample from the lateral left/right ventricular wall & intraventricular septum. Peak systolic (S’), early diastolic (E’) and late diastolic (A’) velocities were recorded. Results Ten preterm infants with structurally normal hearts were recruited. Mean (SD) gestational age was 28 (1.7) weeks and birthweight 1.29 (0.3)kg. There was no significant increase in Right ventricular systolic (5.1cm/sec vs 4.8cm/sec)or diastolic myocardial velocity measures (5.2cm/sec vs 5.1cm/sec) or left myocardial velocity systolic (3.7cm/sec vs 3.9cm/sec) or diastolic (4.1cm/sec vs 4.0cm/sec) measures between those with severe Vitamin D deficiency (<30 nmol/L) and those with low normal levels of Vitamin D. Conclusion Neonates with severe Vitamin D deficiency have similar TDI measures of systolic and diastolic velocity to those with near normal levels. In our small cohort severe Vitamin D deficiency appears to cause no impairment in myocardial contractility.