title: Evaluation of left ventricular contractile function using noninvasively determined single-beat end-systolic elastance in mitral regurgitation: experimental validation and clinical application.
abstract: OBJECTIVE
  We performed this study to validate the single-beat estimation of end-systolic elastance (E(es)) in an animal model of chronic mitral regurgitation (MR) and to use E(es) to predict postoperative left ventricular (LV) systolic function with the noninvasively derived single-beat E(es) (E(es-s)) in patients with MR.
  
  
  METHODS
  Eight sheep with MR were studied under 4 different loading conditions. E(es) was measured as the slope of the end-systolic pressure-volume relationship with a conductance catheter during inferior vena cava occlusion. E(es-s) was calculated using a bilinearly approximated time-varying elastance curve. We also studied 105 patients with MR who had undergone mitral valve repair. All measurements in these patients were performed before surgery and repeated at about 1 week after surgery.
  
  
  RESULTS
  In the animals in a total of 23 different stages, E(es-s) showed a good correlation and agreement with invasively determined E(es) (y = 0.84 x + 0.38; r = 0.8; P < .01, mean difference = 0.1 +/- 0.6 mm Hg/mL). In the clinical study, preoperative E(es-s) (r = 0.77; P < .001) and end-systolic volume index correlated well with postoperative ejection fraction (r = -0.69; P < .001). Multivariate analyses revealed that only E(es-s) was an independent predictor of postoperative LV function. Preoperative E(es-s) less than or equal to 1.0 mm Hg/mL was most predictive for identifying patients with LV dysfunction after surgery (sensitivity 87%; specificity 76%).
  
  
  CONCLUSIONS
  LV end-systolic elastance can be estimated noninvasively and is useful to detect latent LV dysfunction in patients with MR before surgery.
authors.affiliation: Seoul National University Hospital, Seoul, Korea.
authors.forename: Yong Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Michael
authors.initials: M
authors.lastname: Jones
authors.forename: Neil L
authors.initials: NL
authors.lastname: Greenberg
authors.forename: Zoran B
authors.initials: ZB
authors.lastname: Popovic
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bauer
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
authors.forename: Takahiro
authors.initials: T
authors.lastname: Shiota
mesh_terms: D000328:Adult; D000818:Animals; D019560:Echocardiography, Three-Dimensional; D004548:Elasticity; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000502:physiology*; D012372:ROC Curve; D012189:Retrospective Studies; D034561:Sheep, Domestic; D013599:Systole / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*