title: Maturational and adaptive modulation of left ventricular torsional biomechanics: Doppler tissue imaging observation from infancy to adulthood.
abstract: BACKGROUND
  Left ventricular (LV) torsional deformation, based in part on the helical myocardial fiber architecture, is an important component of LV systolic and diastolic performance. However, there is no comprehensive study describing its normal development during childhood and adult life.
  
  
  RESULTS
  Forty-five normal subjects (25 children and 20 adults; aged 9 days to 49 years; divided into 5 groups: infants, children, adolescents, and young and middle-age adults) underwent assessment of LV torsion and untwisting rate by Doppler tissue imaging. LV torsion increased with age, primarily owing to augmentation in basal clockwise rotation during childhood and apical counterclockwise rotation during adulthood. Although LV torsion and untwisting overall showed age-related increases, when normalized by LV length, they showed higher values in infancy and middle age. The proportion of untwisting during isovolumic relaxation was lowest in infancy, increased during childhood, and leveled off thereafter, whereas peak untwisting performance (peak untwisting velocity normalized by peak LV torsion) showed a decrease during adulthood.
  
  
  CONCLUSIONS
  We have shown the maturational process of LV torsion in normal subjects. Net LV torsion increases gradually from infancy to adulthood, but the determinants of this were different in the 2 age groups. The smaller LV isovolumic untwisting recoil during infancy and its decline in adulthood may suggest mechanisms for alterations in diastolic function.
authors.affiliation: Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Notomi
authors.forename: Gowdagere
authors.initials: G
authors.lastname: Srinath
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shiota
authors.forename: Maureen G
authors.initials: MG
authors.lastname: Martin-Miklovic
authors.forename: Lisa
authors.initials: L
authors.lastname: Beachler
authors.forename: Kelly
authors.initials: K
authors.lastname: Howell
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Oryszak
authors.forename: Dimitri G
authors.initials: DG
authors.lastname: Deserranno
authors.forename: Alan D
authors.initials: AD
authors.lastname: Freed
authors.forename: Neil L
authors.initials: NL
authors.lastname: Greenberg
authors.forename: Adel
authors.initials: A
authors.lastname: Younoszai
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001696:Biomechanical Phenomena; D002648:Child; D002675:Child, Preschool; D003971:Diastole; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009038:Motion; D016277:Ventricular Function, Left / Q000502:physiology*