title: Mechanistic features associated with improvement in mitral regurgitation after cardiac resynchronization therapy and their relation to long-term patient outcome.
abstract: BACKGROUND
  Mechanisms of mitral regurgitation (MR) reduction with cardiac resynchronization therapy (CRT) are complex, and their association with long-term outcome is unclear. We sought to elucidate mechanistic features of reduction in MR with CRT, which impact long-term patient survival.
  
  
  RESULTS
  A prospective longitudinal study of 277 patients with heart failure with QRS width ≥ 120 ms and ejection fraction ≤ 35% for CRT was performed. Quantitative echocardiography, including dyssynchrony analysis, was performed at baseline. MR was quantified by color Doppler before and 6 months after CRT. Predefined end points of death, transplant, or left ventricular assist device were tracked during 4 years. There were 114 (48%) patients with CRT with significant MR (≥ moderate) at baseline; of whom 48 (42%) patients had MR improvement, and 24 (19%) patients had MR worsening after CRT. The 66 events (47 deaths, 10 transplantations, and 9 left ventricular assist devices) were strongly associated with significant MR after CRT (hazard ratio, 3.58; 95% confidence interval, 2.18-5.87; P<0.0001). Three echocardiographic features were independently associated with amelioration of significant MR after CRT by multivariable analysis: anteroseptal to posterior wall radial strain dyssynchrony >200 ms, lack of severe left ventricular dilatation (end-systolic dimension index <29 mm/m(2)), and lack of echocardiographic scar at papillary muscle insertion sites (all P<0.05) and, when combined, were additively associated with long-term survival (P=0.0001).
  
  
  CONCLUSIONS
  Significant MR after CRT was strongly associated with less favorable long-term survival. Echocardiographic mechanistic features were identified that were associated with improvement in MR after CRT and favorable long-term survival.
authors.affiliation: Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15213-2582, USA.
authors.forename: Tetsuari
authors.initials: T
authors.lastname: Onishi
authors.forename: Toshinari
authors.initials: T
authors.lastname: Onishi
authors.forename: Josef J
authors.initials: JJ
authors.lastname: Marek
authors.forename: Mohamed
authors.initials: M
authors.lastname: Ahmed
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Haberman
authors.forename: Olusegun
authors.initials: O
authors.lastname: Oyenuga
authors.forename: Evan
authors.initials: E
authors.lastname: Adelstein
authors.forename: David
authors.initials: D
authors.lastname: Schwartzman
authors.forename: Samir
authors.initials: S
authors.lastname: Saba
authors.forename: John
authors.initials: J
authors.lastname: Gorcsan
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy*; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D016896:Treatment Outcome; D018615:Ultrasonography, Doppler, Color / Q000379:methods
keywords: cardiac resynchronization therapy; echocardiography; mitral valve insufficiency