title: Predictors of short-term clinical response to cardiac resynchronization therapy.
abstract: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with symptomatic heart failure and QRS prolongation but there is uncertainty about which patient characteristics predict short-term clinical response.
  
  
  
  In an individual patient meta-analysis of three double-blind, randomized trials, clinical composite score (CCS) at 6 months was compared in patients assigned to CRT programmed on or off. Treatment-covariate interactions were assessed to measure likelihood of improved CCS at 6 months. MIRACLE, MIRACLE ICD, and REVERSE trials contributed data for this analysis (n = 1591). Multivariable modelling identified QRS duration and left ventricular ejection fraction (LVEF) as predictors of CRT clinical response (P < 0.05). The odds ratio for a better CCS at 6 months increased by 3.7% for every 1% decrease in LVEF for patients assigned to CRT-on compared to CRT-off, and was greatest when QRS duration was between 160 and 180 ms.
  
  
  
  In symptomatic chronic heart failure patients (NYHA class II-IV), longer QRS duration and lower LVEF independently predict early clinical response to CRT.
authors.affiliation: Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Linde
authors.affiliation: Division of Cardiovascular Medicine and the Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.
authors.forename: William T
authors.initials: WT
authors.lastname: Abraham
authors.affiliation: Medical University of South Carolina, Charleston, SC, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Gold
authors.affiliation: University of Rennes 1, Rennes, France.
authors.forename: J Claude
authors.initials: JC
authors.lastname: Daubert
authors.affiliation: The Island Medical Program, University of British Columbia, Vancouver, Canada.
authors.forename: Anthony S L
authors.initials: ASL
authors.lastname: Tang
authors.affiliation: Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA.
authors.forename: James B
authors.initials: JB
authors.lastname: Young
authors.affiliation: Medtronic plc, Minneapolis, MN, USA.
authors.forename: Lou
authors.initials: L
authors.lastname: Sherfesee
authors.affiliation: Medtronic plc, Minneapolis, MN, USA.
authors.forename: J Harrison
authors.initials: JH
authors.lastname: Hudnall
authors.affiliation: Medtronic plc, Minneapolis, MN, USA.
authors.forename: Dedra H
authors.initials: DH
authors.lastname: Fagan
authors.affiliation: National Heart and Lung Institute, Imperial College London, London, UK.
authors.forename: John G
authors.initials: JG
authors.lastname: Cleland
mesh_terms: D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D017147:Defibrillators, Implantable; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*
keywords: Cardiac resynchronization therapy; Heart failure; Symptoms