title: Resynchronization/defibrillation for ambulatory heart failure  trial: rationale and trial design.
abstract: OBJECTIVE
  This paper reviews the effect of cardiac resynchronization therapy (CRT) on patients with heart failure symptoms, in particular, in patients with mild symptoms of heart failure. It provides the rationale and design of a randomized controlled trial to determine if CRT, when added to implantable cardioverter defibrillator, will be beneficial in patients with left ventricular dysfunction, ventricular conduction delay and mild heart failure symptoms.
  
  
  RESULTS
  CRT has been demonstrated to improve functional capacity, quality of life, and reduce heart failure hospitalization in patients with advanced symptomatic heart failure, and evidence of a ventricular conduction abnormality on ECG. In patients with milder heart failure symptoms, three randomized controlled trials and observational studies failed to convincingly show improvement of functional status, but demonstrated improved ventricular reverse remodelling with more advanced heart failure patients.
  
  
  CONCLUSIONS
  Two large randomized clinical trials are currently ongoing (RAFT and MADIT-CRT). The results of these trials will determine the efficacy of CRT in patients with systolic heart failure, ventricular conduction abnormality and milder symptoms.
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario, Canada. atang@westerncardiology.ca
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Tang
authors.forename: George A
authors.initials: GA
authors.lastname: Wells
authors.forename: Malcolm
authors.initials: M
authors.lastname: Arnold
authors.forename: Stuart
authors.initials: S
authors.lastname: Connolly
authors.forename: Stefan
authors.initials: S
authors.lastname: Hohnloser
authors.forename: Graham
authors.initials: G
authors.lastname: Nichol
authors.forename: Jean
authors.initials: J
authors.lastname: Rouleau
authors.forename: Robert
authors.initials: R
authors.lastname: Sheldon
authors.forename: Mario
authors.initials: M
authors.lastname: Talajic
mesh_terms: D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012107:Research Design