title: Dobutamine-induced improvement in inferior myocardial contractile function predicts reduction in functional mitral regurgitation: a study using tissue Doppler strain rate imaging.
abstract: BACKGROUND
  left ventricular (LV) remodeling can increase tethering force to mitral valve and functional mitral regurgitation (FMR). Because the relationship between FMR and regional myocardial function has not been quantitatively evaluated, we conducted a quantitative investigation of this association.
  
  
  RESULTS
  the effective regurgitant orifice (ERO) of FMR in 51 patients with depressed LV ejection fraction (32±9%) secondary to ischemic or nonischemic cardiomyopathy was compared with mitral deformation (valve and annulus), global LV remodeling (volume indices, function, and sphericity), and regional myocardial contractile function, as assessed by longitudinal peak systolic strain rate (Ssr) in LV anterior, anteroseptal, inferoseptal, inferior, inferolateral, and anterolateral segments at rest. Low-dose dobutamine (10 μg/kg per minute)-induced changes in ERO were compared with changes in the variables. Multivariable analysis identified the predictors of ERO at rest as mitral valvular tenting (β=0.062; P<0.001), Ssr in the inferior segment (inferior Ssr) (β=-0.178; P<0.001), and LV sphericity (β=0.414; P=0.001) and the predictors of valvular tenting at rest as inferior Ssr (β=-1.680; P<0.001), LV end-systolic volume index (β=0.022; P=0.001), and LV sphericity (β=3.886; P=0.012). Furthermore, dobutamine-induced reduction in ERO was predicted by reduction in valvular tenting (β=0.087; P<0.001) and increase in inferior Ssr (β=-0.082; P<0.001), and dobutamine-induced reduction in valvular tenting was predicted by increase in inferior Ssr (β=-0.860; P<0.001).
  
  
  CONCLUSIONS
  inferior regional myocardial dysfunction was quantitatively associated with mitral valvular tenting and FMR. Moreover, improvement with dobutamine of inferior myocardial contractile function attenuated valvular tenting and FMR. Inferior myocardial contractile function can affect the configuration of the mitral apparatus and predict FMR severity.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tatsumi
authors.forename: Hiroya
authors.initials: H
authors.lastname: Kawai
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sugiyama
authors.forename: Kazuko
authors.initials: K
authors.lastname: Norisada
authors.forename: Toshiya
authors.initials: T
authors.lastname: Kataoka
authors.forename: Tetsuari
authors.initials: T
authors.lastname: Onishi
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Hirata
mesh_terms: D000368:Aged; D002316:Cardiotonic Agents; D004280:Dobutamine; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging*; D009200:Myocardial Contraction / Q000187:drug effects*; D015588:Observer Variation; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*; D020257:Ventricular Remodeling / Q000187:drug effects
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine