title: Contractile reserve induced with dobutamine echocardiography predicts outcome in patients with left ventricular dysfunction and mitral regurgitation.
abstract: OBJECTIVE
  The appropriate management of patients with mitral regurgitation (MR) and left ventricular dysfunction (LVD) is controversial. The study aim was to determine whether the presence of contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) was associated with improved outcomes.
  
  
  METHODS
  Death and heart transplantation were analyzed as the primary outcomes associated with the presence of CR. A total of 125 consecutive patients (96 males, 29 females; mean age 60 +/- 12 years) with left ventricular ejection fraction (LVEF) < or = 35% and hemodynamically significant MR underwent DSE between 1999 and 2005. CR was defined as an increase in LVEF of > or = 10% during dobutamine infusion.
  
  
  RESULTS
  Among 125 patients, 55 (43.0%) showed evidence of CR. Within five years after DSE, 24 patients (34.3%) in the CR- group and seven (12.7%) in the CR+ group had died or required heart transplantation (p < 0.01, log rank). After adjusting for age, baseline LVEF, NYHA class and moderate/severe tricuspid regurgitation (TR), CR remained an independent predictor of time to death or heart transplantation (HR 0.34; 95% CI: 0.15-0.76, p < 0.01). Improvement in the degree of MR was present at one year in 85.0% of CR+ patients, and in 62.5% of CR- patients (p = 0.03). An improvement of 5% in LVEF was noted in the CR+ group, compared to 0% in the CR- group (p = 0.04).
  
  
  CONCLUSIONS
  In patients with advanced LVD and severe MR, CR detected by DSE was associated with significant reductions in the risk of death and heart transplantation.
authors: Robert R
authors: RR
authors: Moss
authors: Simona L
authors: SL
authors: Bar
authors: Mann
authors: M
authors: Chandavimol
authors: Bradley
authors: B
authors: Munt
authors: Christopher R
authors: CR
authors: Thompson
authors: James G
authors: JG
authors: Abel
authors: Karin
authors: K
authors: Humphries
authors: Andrew P
authors: AP
authors: Ignaszewski
mesh_terms: D000368:Aged; D018572:Disease-Free Survival; D025401:Echocardiography, Stress; D005260:Female; D016027:Heart Transplantation; D006439:Hemodynamics; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D009200:Myocardial Contraction; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D016277:Ventricular Function, Left