title: Diastolic wall strain: a simple marker of abnormal cardiac mechanics.
abstract: BACKGROUND
  Diastolic wall strain (DWS), defined using posterior wall thickness (PWT) measurements from standard echocardiographic images (DWS = [PWT(systole)-PWT(diastole)]/PWT(systole)), has been proposed as a marker of left ventricular (LV) diastolic stiffness. However, the equation for DWS is closely related to systolic radial strain, and whether DWS is associated with abnormal cardiac mechanics (reduced systolic strains and diastolic tissue velocities) is unknown. We sought to determine the relationship between DWS and systolic and diastolic cardiac mechanics.
  
  
  METHODS
  We calculated DWS and performed speckle-tracking analysis in a large population- and family-based study (Hypertension Genetic Epidemiology Network [HyperGEN]; N=1907 after excluding patients with ejection fraction [EF] <50% or posterior wall motion abnormalities). We measured global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS, respectively) and early diastolic (e') tissue velocities, and we determined the independent association of DWS with cardiac mechanics using linear mixed effects models to account for relatedness among study participants. We also prospectively performed receiver-operating characteristic (ROC) analysis of DWS for the detection of abnormal cardiac mechanics in a separate, prospective validation study (N=35).
  
  
  RESULTS
  In HyperGEN (age 51 ± 14 years, 59% female, 45% African-American, 57% hypertensive), mean DWS was 0.38 ± 0.05. DWS decreased with increasing comorbidity burden (β-coefficient -0.013 [95% CI -0.015, -0.011]; P<0.0001). DWS was independently associated with GLS, GCS, GRS, and e' velocity (adjusted P<0.05) but not LV chamber compliance (EDV20, P=0.97). On prospective speckle-tracking analysis, DWS correlated well with GLS, GCS, and GRS (R=0.61, 0.57, and 0.73, respectively; P<0.001 for all comparisons). C-statistics for DWS as a diagnostic test for abnormal GLS, GCS, and GRS were: 0.78, 0.79, and 0.84, respectively.
  
  
  CONCLUSIONS
  DWS, a simple parameter than can be calculated from routine 2D echocardiography, is closely associated with systolic strain parameters and early diastolic (e') tissue velocities but not LV chamber compliance.
authors.forename: Senthil
authors.initials: S
authors.lastname: Selvaraj
authors.forename: Frank G
authors.initials: FG
authors.lastname: Aguilar
authors.forename: Eva E
authors.initials: EE
authors.lastname: Martinez
authors.forename: Lauren
authors.initials: L
authors.lastname: Beussink
authors.forename: Kwang-Youn A
authors.initials: KY
authors.lastname: Kim
authors.forename: Jie
authors.initials: J
authors.lastname: Peng
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Lee
authors.forename: Ateet
authors.initials: A
authors.lastname: Patel
authors.forename: Jin
authors.initials: J
authors.lastname: Sha
authors.forename: Marguerite R
authors.initials: MR
authors.lastname: Irvin
authors.forename: Donna K
authors.initials: DK
authors.lastname: Arnett
authors.affiliation: Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, 676 N, St, Clair St,, Suite 600, Chicago, IL 60611, USA. sanjiv.shah@northwestern.edu.
authors.forename: Sanjiv J
authors.initials: SJ
authors.lastname: Shah
mesh_terms: D015415:Biomarkers; D003971:Diastole; D004452:Echocardiography / Q000706:statistics & numerical data; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000706:statistics & numerical data; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D014481:United States / Q000453:epidemiology; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology*
chemical_list: D015415:Biomarkers