title: Assessment of intraventricular time differences in healthy children using two-dimensional speckle-tracking echocardiography.
abstract: BACKGROUND
  Parameters describing intraventricular time differences are increasingly assessed in both adults and children. However, to appreciate the implications of these parameters in children, knowledge of the applicability of adult techniques in children is essential. Hence, the aim of this study was to assess the applicability of speckle-tracking strain-derived parameters in children, paying special attention to age and heart rate dependency.
  
  
  METHODS
  One hundred eighty-three healthy subjects (aged 0-19 years) were included. Left ventricular global peak strain, time to global peak strain, and parameters describing intraventricular time differences were assessed using speckle-tracking strain imaging in the apical two-chamber, three-chamber, and four-chamber views (longitudinal strain) and the parasternal short-axis view (radial and circumferential strain). Parameters describing intraventricular time differences included the standard deviation of time to peak strain and differences in time to peak strain between two specified segments. Age and heart rate dependency were evaluated using regression analysis, and intraobserver and interobserver variability were tested.
  
  
  RESULTS
  Acquisition and analysis of longitudinal six-segment time-strain curves was successful in 94.8% of subjects and radial and circumferential time-strain curves in 89.5%. No clinically significant linear relation was observed between age or heart rate and parameters describing intraventricular time differences. The coefficient of variation of time to global peak strain parameters was <10, while it was >10 for parameters describing intraventricular time differences.
  
  
  CONCLUSIONS
  The feasibility of speckle-tracking strain analysis in children is relatively good. Furthermore, no linear relation was observed between age or heart rate and parameters describing intraventricular time differences. However, the limited reproducibility of some parameters describing intraventricular time differences will confine their applicability in clinical practice.
authors.affiliation: Department of Pediatric Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Liselotte M
authors.initials: LM
authors.lastname: Klitsie
authors.forename: Arno A W
authors.initials: AA
authors.lastname: Roest
authors.forename: Annelies E
authors.initials: AE
authors.lastname: van der Hulst
authors.forename: Theo
authors.initials: T
authors.lastname: Stijnen
authors.forename: Nico A
authors.initials: NA
authors.lastname: Blom
authors.forename: Arend D J
authors.initials: AD
authors.lastname: Ten Harkel
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D012016:Reference Values; D012044:Regression Analysis; D015203:Reproducibility of Results; D016277:Ventricular Function, Left / Q000502:physiology*; D055815:Young Adult