title: Fractionating E-wave deceleration time into its stiffness and relaxation components distinguishes pseudonormal from normal filling.
abstract: BACKGROUND
  Pseudonormal Doppler E-wave filling patterns indicate diastolic dysfunction but are indistinguishable from the normal filling pattern. For accurate classification, maneuvers to alter load or to additionally measure peak E' are required. E-wave deceleration time (DT) has been fractionated into its stiffness (DTs) and relaxation (DTr) components (DT=DTs+DTr) by analyzing E-waves via the parametrized diastolic filling formalism. The method has been validated with DTs and DTr correlating with simultaneous catheterization-derived stiffness (dP/dV) and relaxation (τ) with r=0.82 and r=0.94, respectively. We hypothesize that DT fractionation can (1) distinguish between unblinded (E' known) normal versus pseudonormal age-matched groups with normal left ventricular ejection fraction, and (2) distinguish between blinded (E' unknown) normal versus pseudonormal groups, based solely on E-wave analysis.
  
  
  RESULTS
  Data (763 E-waves) from 15 age-matched, pseudonormal (elevated E/E') and 15 normal subjects were analyzed. Conventional echocardiographic and parametrized diastolic filling stiffness (k) and relaxation (c) parameters and DTs and DTr were compared. Conventional diastolic function parameters did not differentiate between unblinded groups, whereas k, c (P<0.001) and DTs, DTr (P<0.001) did. Independent, blinded (E' not provided) analysis of 42 subjects (30 subjects from unblinded training set and 12 additional subjects from validation set, 581 E-waves) showed that R (=DTr/DT) had high sensitivity (0.90) and specificity (0.86) in differentiating pseudonormal from normal once E' revealed actual classification.
  
  
  CONCLUSIONS
  arametrized diastolic filling-based E-wave analysis (k, c or DTs and DTr) can differentiate normal versus pseudonormal filling patterns without requiring knowledge of E'.
authors.affiliation: From the Cardiovascular Biophysics Laboratory, Cardiovascular Division (S.M., S.Z., S.J.K), Department of Physics (S.M., S.Z., S.J.K.), and Department of Medicine, Cardiovascular Division (S.J.K), Washington University School of Medicine, St. Louis, MO.
authors.forename: Sina
authors.initials: S
authors.lastname: Mossahebi
authors.affiliation: From the Cardiovascular Biophysics Laboratory, Cardiovascular Division (S.M., S.Z., S.J.K), Department of Physics (S.M., S.Z., S.J.K.), and Department of Medicine, Cardiovascular Division (S.J.K), Washington University School of Medicine, St. Louis, MO.
authors.forename: Simeng
authors.initials: S
authors.lastname: Zhu
authors.affiliation: From the Cardiovascular Biophysics Laboratory, Cardiovascular Division (S.M., S.Z., S.J.K), Department of Physics (S.M., S.Z., S.J.K.), and Department of Medicine, Cardiovascular Division (S.J.K), Washington University School of Medicine, St. Louis, MO. sjk@wuphys.wustl.edu.
authors.forename: Sándor J
authors.initials: SJ
authors.lastname: Kovács
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003971:Diastole; D018619:Echocardiography, Doppler, Pulsed; D004548:Elasticity; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013318:Stroke Volume; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016277:Ventricular Function, Left
keywords: Doppler echocardiography; diastole; left ventricle; relaxation; stiffness