title: Maturational and growth-related changes in left ventricular longitudinal strain and strain rate measured by two-dimensional speckle tracking echocardiography in healthy pediatric population.
abstract: OBJECTIVE
  We aimed to evaluate myocardial strain and strain rate (SR) by novel 2-dimensional speckle tracking echocardiography in a large pediatric cohort (1) to establish their normal values and (2) to discern the influence of maturation and cardiac growth on them.
  
  
  METHODS
  Echocardiograms of 284 consecutive subjects of a healthy pediatric cohort aged between birth and 18 years were analyzed by vector velocity imaging software to measure longitudinal systolic strain (epsilon) and systolic and diastolic SR in left ventricular septal and lateral segments. Regression analysis was performed to determine the effect of aging and cardiac growth on epsilon and SR.
  
  
  RESULTS
  Longitudinal epsilon (septal -18.30% +/- 6.67% and lateral -20.68% +/- 8.08%) did not change significantly with maturation and declining heart rate from birth to 18 years. Systolic and early diastolic SR declined until age 5 to 10 years. Longitudinal epsilon significantly (P < .05) correlated with left ventricular growth.
  
  
  CONCLUSIONS
  This study establishes reference values for longitudinal epsilon and SR and reveals that epsilon is relatively independent of maturational changes, lending it as a tool for cardiac evaluation across differing ages in pediatric subjects.
authors.affiliation: Division of Pediatric Cardiology, Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri 63110, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Lorch
authors.forename: Achiau
authors.initials: A
authors.lastname: Ludomirsky
authors.forename: Gautam K
authors.initials: GK
authors.lastname: Singh
mesh_terms: D000293:Adolescent; D000375:Aging / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography / Q000379:methods*; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D016277:Ventricular Function, Left / Q000502:physiology*