title: Serial assessment of right ventricular function using tissue Doppler imaging in preterm infants within 7 days of life.
abstract: BACKGROUND
  We aimed to evaluate right ventricular (RV) function longitudinally using tissue Doppler imaging (TDI) echocardiography in preterm infants.
  
  
  METHODS
  We selected 101 very-low-birth-weight (VLBW) infants for the study. Echocardiographic examinations including TDI were performed serially within 7days of life. Pulsed-Doppler TDI waveforms were recorded at the tricuspid valve annulus, and peak systolic velocities (Sa), early diastolic velocities (Ea), and late diastolic velocities (Aa) were measured.
  
  
  RESULTS
  Sa, Ea and Aa were all reduced significantly from 3h to 12h, and then increased gradually thereafter. These three velocities also increased with gestational age in the early neonatal period. The ratio of Ea to Aa (Ea/Aa) did not change significantly within the first week of life. The ratio of E to Ea (E/Ea) in VLBW infants also seemed to remain stable from birth to day 7. The values of Sa appeared to be associated with cardiac output in the early neonatal period. Both Sa and Aa in intubated infants were significantly higher than in non-intubated infants.
  
  
  CONCLUSIONS
  RV TDI velocities of preterm infants in the early neonatal period are influenced by gestational age, postnatal age, and respiratory status, although the RV E/Ea ratio appears to be almost stable throughout the neonatal period. Our findings may provide some basis for assessment of RV function in critically ill preterm infants.
authors.affiliation: Department of Pediatrics, International University of Health and Welfare Hospital, 537-3 Iguchi, Nasushiobara-shi, Tochigi 329-2763, Japan. Electronic address: m-m-mura@ya2.so-net.ne.jp.
authors.forename: Masanori
authors.initials: M
authors.lastname: Murase
authors.affiliation: Department of Pediatrics, Kakogawa Municipal Hospital, Kakogawa, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Morisawa
authors.affiliation: Kobe Children's First-aid Center, Kobe, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Ishida
mesh_terms: D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000502:physiology*; D008297:Male; D016278:Ventricular Function, Right
keywords: Echocardiography; Preterm infants; Right ventricle; Tissue Doppler imaging