title: Cardiac Function After the Immediate Transitional Period in Very Preterm Infants Using Speckle Tracking Analysis.
abstract: BACKGROUND
  The postnatal period in preterm infants involves multiple physiologic changes starting directly after birth and continuing for days or weeks. To recognize and treat compromise, it is important to measure cardiovascular function. We used a novel technique (speckle tracking echocardiography, STE) to measure cardiac function in this period.
  
  
  METHODS
  We obtained cardiac ultrasound images at day 3, 7, 14, 21 and 28 in preterm infants <30-week gestation. Conventional measures included cardiac size, left ventricular stroke volume, atrial volume and the patent ductus arteriosus (PDA). Four chamber images were analyzed with STE, which provided parameters of left ventricular volume, longitudinal deformation and myocardial velocities.
  
  
  RESULTS
  Images of 54 infants (gestational age 23-29 weeks) were analyzed. STE-derived stroke volume correlated well with conventional echocardiography-derived stroke volume, but agreement was suboptimal. Most STE parameters showed good reliability. All volume parameters and systolic and atrial velocities increased over time. Cardiac deformation and early diastolic velocity did not change. A PDA was associated with 33 % increased stroke volume at day 3 up to 98 % at day 28 with a spherically enlarged heart and increased filling pressure.
  
  
  CONCLUSIONS
  Speckle tracking echocardiography analysis is a feasible and reliable technique that can simultaneously obtain systolic and diastolic volumes, longitudinal deformation and myocardial velocities from one ultrasound window. Preterm hearts maintain cardiac function well during the first weeks of life, even with increased preload as a consequence of a PDA.
authors.affiliation: Neonatal Intensive Care Unit, John Hunter Children's Hospital, Lookout Road, New Lambton, NSW, 3205, Australia. koert.dewaal@hnehealth.nsw.gov.au.|University of Newcastle, New Lambton, NSW, Australia. koert.dewaal@hnehealth.nsw.gov.au.
authors.forename: Koert
authors.initials: K
authors.lastname: de Waal
authors.affiliation: Neonatal Intensive Care Unit, John Hunter Children's Hospital, Lookout Road, New Lambton, NSW, 3205, Australia.|University of Newcastle, New Lambton, NSW, Australia.
authors.forename: Nilkant
authors.initials: N
authors.lastname: Phad
authors.affiliation: Neonatal Intensive Care Unit, John Hunter Children's Hospital, Lookout Road, New Lambton, NSW, 3205, Australia.|University of Newcastle, New Lambton, NSW, Australia.
authors.forename: Anil
authors.initials: A
authors.lastname: Lakkundi
authors.affiliation: University of Newcastle, New Lambton, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Tan
mesh_terms: D001315:Australia; D003971:Diastole; D004374:Ductus Arteriosus, Patent / Q000000981:diagnostic imaging*; D004452:Echocardiography; D005260:Female; D005865:Gestational Age; D006321:Heart / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D015203:Reproducibility of Results; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: Cardiac output; Hemodynamics; Newborn; Patent ductus arteriosus; Speckle tracking echocardiography