Presented at the Neonatal Society 2009 Spring Meeting.
Parikh R1, Negrine RJS1, Chikermane A2, Ewer AK1,3
1 Neonatal Intensive Care Unit, Birmingham Women’s Hospital, UK
2 Department of Paediatric Cardiology, Birmingham Children’s Hospital, UK
3 School of Clinical and Experimental Medicine, University of Birmingham, UK
Background: Assessment of neonatal cardiac function has significant limitations. Tissue Doppler Imaging (TDI) of the myocardium is well established as a method of assessing adult cardiac function (1) and we have recently reported its use in neonates (2). Haemodynamically significant Ductus Arteriosus (HSDA) can result in significant morbidity in VLBW infants (3) and is commonly treated with indomethacin (IM). The effect of HSDA, and its treatment, on myocardial function is largely unknown.
Objective: To assess myocardial velocities in preterm neonates with HSDA before and after IM treatment using TDI.
Methods: VLBW neonates underwent echocardiography by one investigator (RP). Those with HSDA (Ductal Diameter > 2.5mm and LA:Ao ratio > 1.5 ) on day 3 or day 4 were treated with IM according to local protocol. Echocardiography was repeated 3 days post IM treatment. Myocardial velocities were acquired from an apical four chamber view. A Doppler pulse-wave sample gate of 0.12cm was positioned at the lateral tricuspid annulus, lateral mitral annulus and basal interventricular septum. Peak velocities in systole, early diastole and late diastole were obtained from each site. Average readings were taken from 3-5 cardiac cycles. Ethical approval was obtained from the Birmingham Research Ethics Committee.
Results: Eight subjects with HSDA were recruited; median gestational age 26 weeks (range 25-28) and Birthweight 839g (range 540-1060, SD 161g). Mean (SD) velocities (cm/sec) obtained are shown:
Consistent with our previous data, all patients demonstrated significantly greater velocities at the tricuspid annulus than the mitral annulus with the septal velocities lowest at all sites and phases of the cardiac cycle(p<0.0001). The pre-treatment group demonstrated lower velocities at the tricuspid and mitral annuli than preterm babies without PDA in our previous study, suggesting relative myocardial dysfunction with HSDA. There was a significant increase in all velocities after IM (p<0.0001).
Conclusion: Myocardial velocities in preterm infants with HSDA are lower than those without PDA and increase after treatment with indomethacin suggesting an improvement in myocardial function Our pilot study suggests that TDI may be a useful tool in the assessment of myocardial dysfunction in babies with HSDA.
References
1. Weidemann F et al. Pediatric Cardiology 2002;23:292 – 306.
2. Negrine et al. ArchDisChild – F&N 2008;93(Supp 1):Fa6.
3. McNamara et al. Arch. Dis. Child. Fetal Neonatal Ed. 2007;92;424-427.