title: Normal rotational, torsion and untwisting data in children, adolescents and young adults.
abstract: BACKGROUND
  Left ventricular (LV) torsion and untwisting are important components of LV performance, but there is little information on the effect of age, particularly in younger populations.
  
  
  METHODS
  LV rotation and LV rotation rate, torsion, recoiling, and untwisting were measured in normal subjects (n=111) aged 3 to 40 years (mean age, 19.3 years) using speckle-tracking imaging.
  
  
  RESULTS
  LV torsion increased with age because of the augmentation of apical LV rotation, but this disappeared when normalized by LV length. Although peak LV torsion and apical LV rotation increased with age, the normalized peak torsion rate decreased. As well, the peak untwisting rate decreased with age and was enhanced when normalized by LV length. Younger hearts demonstrated greater untwisting and recoiling of the apex during isovolumic relaxation and early diastole. The time difference between apical and basal events decreased with advancing age.
  
  
  CONCLUSIONS
  The heart maintains a constant LV torsion and LV rotation profile when normalized by length and cardiac cycle. Younger hearts tend to twist, untwist, and deform faster.
authors.affiliation: Department of Pediatrics, Division of Pediatric Cardiology, University of Alberta and Stollery Children's Hospital, Edmonton, Alberta, Canada.
authors.forename: Ken
authors.initials: K
authors.lastname: Takahashi
authors.forename: Ghassan
authors.initials: G
authors.lastname: Al Naami
authors.forename: Richard
authors.initials: R
authors.lastname: Thompson
authors.forename: Akio
authors.initials: A
authors.lastname: Inage
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Mackie
authors.forename: Jeffrey F
authors.initials: JF
authors.lastname: Smallhorn
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007223:Infant; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D016277:Ventricular Function, Left / Q000502:physiology*; D055815:Young Adult