title: Left Ventricular Longitudinal and Circumferential Layer-Specific Myocardial Strains and Their Determinants in Healthy Subjects.
abstract: BACKGROUND
  The reference values and impact of physiologic variables on echocardiographic quantification of left ventricular (LV) longitudinal and circumferential layer-specific myocardial strains in large series of healthy persons remain unknown. This study prospectively investigated the impact of age, gender, and other physiologic parameters on LV longitudinal and circumferential layer-specific myocardial strains.
  
  
  METHODS
  119 healthy volunteers (age range, 22-76; 50% women) underwent echocardiography. Short-axis (for circumferential strain) and apical (for longitudinal strain) views were analyzed using modified speckle tracking software enabling the analysis of strains in three myocardial layers.
  
  
  RESULTS
  In normal subjects, longitudinal and circumferential strain was highest in the endocardium and lowest in the epicardium, longitudinal and circumferential three-layer strain was highest in the apex and lowest in the base. The mean global longitudinal strain in the endocardial layer (GLS-endo), in the mid-myocardial layer (GLS-mid) and in the epicardial layer (GLS-epi) were -24.3 ± 3.1%, -21.3 ± 2.9%, and -18.9 ± 2.8%, respectively. Gender, HR, and SV (stroke volume) were independent predictors of GLS-endo, GLS-mid, and GLS-epi. The mean global circumferential strain in the endocardial layer (GCS-endo), in the mid-myocardial layer (GCS-mid) and in the epicardial layer (GCS-epi) were -34.3 ± 4.4%, -20.5 ± 3.0%, and -11.8 ± 2.7%, respectively. HR independently predicted GCS-endo, GCS-mid, and GCS-epi.
  
  
  CONCLUSIONS
  Three-layer analysis of longitudinal and circumferential strain using two-dimensional speckle tracking imaging (2DSTI) can be performed on a clinical basis and may become an important method for the assessment of real time, quantitative global, and regional LV function.
authors.affiliation: Division of Echocardiography and the Division of Cardiology, Zhongshan Hospital of Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai Institute of Medical Imaging, Shanghai, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Shi
authors.affiliation: Division of Echocardiography and the Division of Cardiology, Zhongshan Hospital of Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai Institute of Medical Imaging, Shanghai, China.
authors.forename: Cuizhen
authors.initials: C
authors.lastname: Pan
authors.affiliation: Division of Echocardiography and the Division of Cardiology, Zhongshan Hospital of Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai Institute of Medical Imaging, Shanghai, China.
authors.forename: Dehong
authors.initials: D
authors.lastname: Kong
authors.affiliation: Division of Echocardiography and the Division of Cardiology, Zhongshan Hospital of Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai Institute of Medical Imaging, Shanghai, China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Division of Echocardiography and the Division of Cardiology, Zhongshan Hospital of Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai Institute of Medical Imaging, Shanghai, China.
authors.forename: Xianhong
authors.initials: X
authors.lastname: Shu
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D002681:China; D019245:Compressive Strength / Q000502:physiology; D004452:Echocardiography / Q000379:methods* / Q000592:standards*; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods* / Q000592:standards*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods / Q000592:standards; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: 2D speckle tracking; myocardial layers; physiologic determinants; reference range; strain