title: Evolution of left ventricular function in the preterm infant.
abstract: BACKGROUND
  The aim of this study was to evaluate left ventricular function in preterm infants from 28 days to near term using echocardiography.
  
  
  METHODS
  Thirty clinically stable preterm infants delivered at <30 weeks' gestational age were prospectively enrolled. At 28 days, conventional, tissue Doppler, and speckle-tracking echocardiography evaluations of left ventricular function were performed, with comparison made to findings in 30 healthy term infants of similar postnatal age. Sixteen preterm infants underwent repeat examinations near term.
  
  
  RESULTS
  Compared with controls, preterm infants at 28 days had decreased peak mitral valve (MV) E-wave velocities (P < .01), E/A ratios (P < .0001), annular e' velocities (P < .0001), and e'/a' ratios (P < .0001); increased MV E/e' ratios (P < .01); and lower basal circumferential early diastolic and higher late diastolic strain rates. No significant differences were found in fractional shortening, ejection fraction, and longitudinal or circumferential strain and strain rate between preterm infants and controls. Although preterm infants at 28 days had higher heart rates compared with controls (161 ± 15 vs 142 ± 16 beats/min), no significant correlations existed between heart rate and MV E, E/A ratio, e', e'/a' ratio, and E/e' ratio. Near term, the differences in diastolic function persisted, including decreased MV e'/a' ratio (P < .05), increased E/e' ratio (P < .01), and increased late diastolic strain rate.
  
  
  CONCLUSIONS
  Clinically stable preterm infants have normal left ventricular systolic function but altered diastolic function, with greater dependence on atrial contraction, the latter of which persists despite nearing term. These findings may be relevant to the management of preterm infants and may relate to the longer term myocardial dysfunction observed in affected adults.
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Akiko
authors.initials: A
authors.lastname: Hirose
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Nee S
authors.initials: NS
authors.lastname: Khoo
authors.affiliation: Department of Pediatrics, Division of Neonatology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Khalid
authors.initials: K
authors.lastname: Aziz
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Najlaa
authors.initials: N
authors.lastname: Al-Rajaa
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Jutta
authors.initials: J
authors.lastname: van den Boom
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Winnie
authors.initials: W
authors.lastname: Savard
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Brooks
authors.affiliation: Fetal & Neonatal Cardiology Program, Department of Pediatrics, Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada; Department of Obstetrics and Gynecology, Women's & Children's Health Research Institute, Mazankowski Alberta Heart Institute, Cardiovascular Research Centre, University of Alberta, Edmonton, Alberta, Canada. Electronic address: lisa.hornberger@albertahealthservices.ca.
authors.forename: Lisa K
authors.initials: LK
authors.lastname: Hornberger
mesh_terms: D004452:Echocardiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007231:Infant, Newborn; D007234:Infant, Premature / Q000254:growth & development* / Q000502:physiology*; D008297:Male; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal / Q000379:methods*; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Echocardiography; Myocardial function; Premature infant