title: Inter- and intraobserver consistency in LV myocardial strain measurement using a novel multi-layer technique in patients with severe aortic stenosis and preserved LV ejection fraction.
abstract: BACKGROUND
  A new transthoracic echocardiography (TTE) technique allows multi-layer measurement of left ventricular (LV), endocardial, epicardial, and whole layer myocardial strain. We evaluated interobserver and intraobserver TTE reproducibility for 2D LV global longitudinal (GLS) and circumferential strain (GCS) estimates using data from severe aortic stenosis (AS) subjects with preserved LV ejection fraction (EF).
  
  
  METHODS
  Twenty severe AS subjects (11 male; mean age, 75±7years; LV EF >50%) underwent TTE (Vivid E9, GE Healthcare). Quantitative strain measurements of whole, endocardial, and epicardial layers were performed. GLS was defined as all 17 averaged LV segments, according to the American Heart Association classification. GCS was measured at the levels of the mitral valve, papillary muscle, and apex.
  
  
  RESULTS
  Interobserver correlation coefficients in whole, endocardial, and epicardial layers for GLS estimates were 0.81, 0.83, and 0.80, respectively, whereas those for GCS estimates were 0.38, 0.56, and 0.19, respectively, for the mitral valve, 0.44, 0.54, and 0.36, respectively, for the papillary muscle, and 0.55, 0.29, and 0.59, respectively, for the apex. Intraobserver correlation coefficients in whole, endocardial, and epicardial layers for GLS estimates were 0.97, 0.97, and 0.94, respectively, whereas those for GCS estimates were 0.86, 0.81, and 0.50 , respectively, for the mitral valve, 0.56, 0.72, and 0.28, respectively, for the papillary muscle, and 0.70, 0.69, and 0.62, respectively, for the apex.
  
  
  CONCLUSIONS
  In severe AS subjects with preserved LVEF, inter- and intra-observer TTE reproducibility in whole, endocardial, and epicardial layers were more consistent for 2D LV GLS than for 2D LVGCS.
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Koya
authors.initials: K
authors.lastname: Ozawa
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, Chiba, Japan. Electronic address: nobusada@w8.dion.ne.jp.
authors.forename: Nobusada
authors.initials: N
authors.lastname: Funabashi
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kamata
authors.affiliation: Department of Cardiovascular Medicine, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kobayashi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015331:Cohort Studies; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*