title: Conventional versus biventricular pacing in heart failure and bradyarrhythmia: the COMBAT study.
abstract: BACKGROUND
  Worsening in clinical and cardiac status has been noted after chronic right ventricular pacing, but it is uncertain whether atriobiventricular (BiVP) is preferable to atrio-right ventricular pacing (RVP). Conventional versus Multisite Pacing for BradyArrhythmia Therapy study (COMBAT) sought to compare BiVP versus RVP in patients with symptomatic heart failure (HF) and atrioventricular (AV) block.
  
  
  RESULTS
  COMBAT is a prospective multicenter randomized double blind crossover study. Patients with New York Heart Association functional class (FC) II-IV, left ventricular ejection fraction (LVEF) <40%, and AV block as an indication for pacing were enrolled. All patients underwent biventricular system implantation and then were randomized to receive successively (group A) RVP-BiVP-RVP, or (group B) BiVP-RVP-BiVP. At the end of each 3-month crossover period, patients were evaluated according to Quality of Life (QoL), FC, echocardiographic parameters, 6-Minute Walk Test (6MWT), and peak oxygen consumption (VO(2 max)). Sixty patients were enrolled, and the mean follow-up period was 17.5 +/- 10.7 months. There were significant improvements in QoL, FC, LVEF, and left ventricular end-systolic volume with BiVP compared with RVP. The effects of pacing mode on 6MWT and VO(2 max) were not significantly different. Death occurred more frequently with RVP.
  
  
  CONCLUSIONS
  In patients with systolic HF and AV block requiring permanent ventricular pacing, BiVP is superior to RVP and should be considered the preferred pacing mode.
authors.affiliation: Pacemaker Clinic, Heart Institute (InCor), University of São Paulo Medical School, Brazil. martino@incor.usp.br
authors.forename: Martino
authors.initials: M
authors.lastname: Martinelli Filho
authors.forename: Sérgio Freitas
authors.initials: SF
authors.lastname: de Siqueira
authors.forename: Roberto
authors.initials: R
authors.lastname: Costa
authors.forename: Oswaldo T
authors.initials: OT
authors.lastname: Greco
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Moreira
authors.forename: Andre
authors.initials: A
authors.lastname: D'avila
authors.forename: E Kevin
authors.initials: EK
authors.lastname: Heist
mesh_terms: D000328:Adult; D000368:Aged; D001919:Bradycardia / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies