title: Durability of the survival effect of cardiac resynchronization therapy by level of left ventricular functional improvement: fate of "nonresponders".
abstract: BACKGROUND
  Although improvement in left ventricular (LV) function has been shown to portend superior short-term outcomes in patients with heart failure undergoing cardiac resynchronization therapy (CRT), the durability of this effect at 5 years has not been established.
  
  
  OBJECTIVE
  To determine the long-term outcomes of patients undergoing CRT on the basis of the degree of echocardiographic response.
  
  
  METHODS
  We extracted clinical data on a cohort of 880 consecutive patients undergoing the new implantation of a CRT device between September 30, 2003, and August 6, 2007. Patients with an ejection fraction (EF) ≤35% undergoing initial CRT implantation, with an available pre-CRT and follow-up echocardiogram, were included in the final cohort. On the basis of changes in LVEF, patients were categorized into "nonresponders" (change in EF ≤4%), "responders" (EF change 5%-20%), and "super-responders" (change in EF >20%). A Cox multivariate model was performed to determine the effect of response on long-term survival free of LV assist device or heart transplant.
  
  
  RESULTS
  A total of 526 patients met inclusion criteria, of whom 196 (37.3%) were classified as nonresponders, 236 (44.9%) as "responders," and 94 (17.9%) as "super-responders." In multivariate analysis, "super-responders" had the best survival and nonresponders the worst over a mean of follow-up of 5.3 ± 2.4 years. At 5 years, survival free of LV assist device or heart transplant among super-responders was 82%; responders, 70%; and nonresponders, 48%.
  
  
  CONCLUSIONS
  In patients with heart failure undergoing CRT, survival benefit is durable at 5 years of follow-up and its degree intimately tied to the level of improvement in ventricular function. The prognosis of nonresponders is exceptionally poor.
authors.affiliation: Division of Cardiology, The Johns Hopkins Hospital, Cleveland, Ohio. Electronic address: jrickar5@jhmi.edu.
authors.forename: John
authors.initials: J
authors.lastname: Rickard
authors.affiliation: Division of Cardiology, The Johns Hopkins Hospital, Cleveland, Ohio.
authors.forename: Alan
authors.initials: A
authors.lastname: Cheng
authors.affiliation: Division of Cardiology, The Johns Hopkins Hospital, Cleveland, Ohio.
authors.forename: David
authors.initials: D
authors.lastname: Spragg
authors.affiliation: Division of Cardiology, The Johns Hopkins Hospital, Cleveland, Ohio.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Bansal
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Mark
authors.initials: M
authors.lastname: Niebauer
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Bryan
authors.initials: B
authors.lastname: Baranowski
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Cantillon
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Tchou
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Grimm
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: W H Wilson
authors.initials: WH
authors.lastname: Tang
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Wilkoff
authors.affiliation: Heart and Vascular Institute Cleveland Clinic, Cleveland, Ohio.
authors.forename: Niraj
authors.initials: N
authors.lastname: Varma
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000628:therapy*; D006801:Humans; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000628:therapy*; D020257:Ventricular Remodeling
keywords: Cardiac resynchronization therapy; Long-term outcomes; Remodeling