title: Real-time transthoracic three dimensional echocardiography: normal reference data for left ventricular dyssynchrony in adolescents.
abstract: BACKGROUND
  Since the introduction of cardiac resynchronization therapy, the assessment of left ventricular (LV) dyssynchrony has become increasingly important. Real-time three-dimensional echocardiography (RT-3DE) is one of the methods that is increasingly used. However, normal reference data in a young population are scarce.
  
  
  METHODS
  RT-3DE was performed in 73 healthy adolescents aged 12 to 18 years. A systolic dyssynchrony index was derived from the dispersion of time to minimum regional volume for all 16 LV segments.
  
  
  RESULTS
  Acquisition of RT-3DE data sets was feasible in 67 of 73 subjects (92%). LV end-diastolic volume and LV end-systolic volume were 99+/-25 and 41+/-15 mL, respectively. All controls had highly synchronized segmental function (systolic dyssynchrony index, 1.26+/-0.53%). Dyssynchrony was independent of age, weight, or length. Interobserver variability for the dyssynchrony index was 2+/-2 ms and 0.3+/-0.2% for the absolute and heart rate-corrected values, respectively. Intraobserver variability was 2.0+/-0.07 ms and 0.0+/-0.27%, respectively.
  
  
  CONCLUSIONS
  RT-3DE could be performed in most healthy adolescents with good interobserver and intraobserver variability. Highly synchronized segmental function was present and was independent of age, weight, or length.
authors.affiliation: Department of Pediatric Cardiology, Erasmus Medical Center-Sophia, Rotterdam, The Netherlands. a.d.j.ten_harkel@lumc.nl
authors.forename: A D J
authors.initials: AD
authors.lastname: Ten Harkel
authors.forename: M
authors.initials: M
authors.lastname: Van Osch-Gevers
authors.forename: W A
authors.initials: WA
authors.lastname: Helbing
mesh_terms: D000293:Adolescent; D002648:Child; D003199:Computer Systems; D004452:Echocardiography / Q000706:statistics & numerical data*; D019560:Echocardiography, Three-Dimensional / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*