title: Post-transitional adaptation of the left heart in uncomplicated, very preterm infants.
abstract: BACKGROUND
  The postnatal period in preterm infants involves multiple physiological changes occurring immediately after birth and continuing for days or weeks. To recognise and treat compromise, it is important to measure cardiovascular function. The aim of this study was to describe longitudinal left ventricular function using conventional and novel echocardiography techniques in preterm infants who did not experience significant antenatal or postnatal complications and treatments.
  
  
  METHODS
  We prospectively obtained cardiac ultrasound images at days 3, 7, 14, 21, and 28 in 25 uncomplicated, preterm infants <30 weeks of gestation. Speckle tracking analysis of the four chambers and short-axis images provided parameters of left ventricular volume, deformation, and basal myocardial velocities. The patent ductus arteriosus, cardiac dimensions, and atrial volume were also measured.
  
  
  RESULTS
  Stroke volume increased by 24% during the study period (1.05-1.30 ml/kg, p<0.05). Cardiac length, diameter, and systolic basal myocardial velocity increased with unchanged wall stress and deformation parameters. Diastolic function parameters resembled that of the fetus with predominance of atrial contraction compared with early diastolic velocities. Blood pressure and estimates of left ventricular filing pressure increased, suggesting that left ventricular compliance did not change in this period.
  
  
  CONCLUSIONS
  Stroke volume increased in the first 28 days after preterm birth. The preterm heart adapted by increasing its size, while maintaining systolic and atrial function, independent of early diastolic maturation. Longitudinal deformation of the left ventricle remained unchanged, suggesting relatively preserved function with maturation.
authors.affiliation: 1Neonatal Intensive Care Unit,John Hunter Children's Hospital,Newcastle,Australia.
authors.forename: Koert
authors.initials: K
authors.lastname: De Waal
authors.affiliation: 1Neonatal Intensive Care Unit,John Hunter Children's Hospital,Newcastle,Australia.
authors.forename: Nilkant
authors.initials: N
authors.lastname: Phad
authors.affiliation: 1Neonatal Intensive Care Unit,John Hunter Children's Hospital,Newcastle,Australia.
authors.forename: Anil
authors.initials: A
authors.lastname: Lakkundi
authors.affiliation: 2University of Newcastle,Newcastle,New South Wales,Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Tan
mesh_terms: D000222:Adaptation, Physiological; D002306:Cardiac Volume / Q000502:physiology; D015150:Echocardiography, Doppler; D005260:Female; D005865:Gestational Age; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D062071:Infant, Extremely Premature / Q000502:physiology*; D007231:Infant, Newborn; D008297:Male; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Speckle tracking echocardiography; left ventricular function; preterm infant; reference values