title: The influence of left ventricular ejection fraction on the effectiveness of cardiac resynchronization therapy: MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy).
abstract: OBJECTIVE
  The aim of this study was to evaluate the relationship between left ventricular (LV) ejection fraction and clinical outcome to cardiac resynchronization therapy (CRT) in mild heart failure patients enrolled in MADIT-CRT [corrected].
  
  
  BACKGROUND
  Left ventricular ejection fraction (LVEF) is a surrogate marker of heart failure (HF) status and associated risk. Data on the effectiveness of cardiac resynchronization therapy with defibrillator (CRT-D) in patients with mild HF and better LVEF are limited.
  
  
  METHODS
  In the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) study, the echocardiography core laboratory assessed baseline LVEF independent of the enrolling centers and identified a range of LVEFs, including those >30% (i.e., beyond the eligibility criteria). Echocardiographic response with CRT, defined as percent change in left ventricular end-diastolic volume (LVEDV), was analyzed in 3 prespecified LVEF groups: >30%, 26% to 30%, and ≤25%. The primary endpoint was HF or death. Secondary endpoint included all-cause mortality.
  
  
  RESULTS
  LVEF was evaluated in 1,809 study patients. There were 696 (38%) patients with LVEF >30% (in the range of 30.1% to 45.3%); 914 patients (50.5%) with LVEF 26% to 30%; and 199 patients with LVEF ≤25% (11%). The mean reduction in LVEDV with CRT-D therapy at the 1-year follow-up was directly related to increasing LVEF (LVEF >30%: 22.3%; LVEF 26% to 30%: 20.1%; and LVEF ≤25%: 18.7% reduction, respectively [p = 0.001]). CRT-D treatment similarly reduced the risk of HF/death in patients with LVEF >30% (hazard ratio [HR]: = 0.56 [95% confidence interval (CI): 0.39 to 0.82], p = 0.003), LVEF 26% to 30% (HR: 0.67: [95% CI: 0.50 to 0.90], p = 0.007), and LVEF ≤25% (HR: 0.57 [95% CI: 0.35 to 0.95], p = 0.03; all p values for LVEF-by-treatment interactions >0.1).
  
  
  CONCLUSIONS
  In MADIT-CRT, the clinical benefit of CRT was evident regardless of baseline LVEF, including those with LVEF >30%, whereas the echocardiographic response was increased with increasing LVEF, indicating that CRT might benefit patients with better LVEF. (Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy [MADIT-CRT]; NCT00180271).
authors: University of Rochester Medical Center, Rochester, New York; Semmelweis University, Heart Center, Budapest, Hungary. valentina.kutyifa@heart.rochester.edu
authors: Valentina
authors: V
authors: Kutyifa
authors: Axel
authors: A
authors: Kloppe
authors: Wojciech
authors: W
authors: Zareba
authors: Scott D
authors: SD
authors: Solomon
authors: Scott
authors: S
authors: McNitt
authors: Slava
authors: S
authors: Polonsky
authors: Alon
authors: A
authors: Barsheshet
authors: Bela
authors: B
authors: Merkely
authors: Bernd
authors: B
authors: Lemke
authors: Vivien Klaudia
authors: VK
authors: Nagy
authors: Arthur J
authors: AJ
authors: Moss
authors: Ilan
authors: I
authors: Goldenberg
mesh_terms: D058406:Cardiac Resynchronization Therapy; D017147:Defibrillators, Implantable; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume / Q000502:physiology*