title: Comparative effects of permanent biventricular and right-univentricular pacing in heart failure patients with chronic atrial fibrillation.
abstract: BACKGROUND
  One third of chronic heart failure patients have major intraventricular conduction and uncoordinated ventricular contraction. Non-controlled studies suggest that biventricular pacing may improve haemodynamics and well-being by reducing ventricular asynchrony. The aim of this trial was to assess the clinical efficacy and safety of this new therapy in patients with chronic atrial fibrillation.
  
  
  METHODS
  Fifty nine NYHA class III patients with left ventricular systolic dysfunction, chronic atrial fibrillation, slow ventricular rate necessitating permanent ventricular pacing, and a wide QRS complex (paced width >or=200 ms), were implanted with transvenous biventricular-VVIR pacemakers. This single-blind, randomized, controlled, crossover study compared the patients' parameters, as monitored during two 3-month treatment periods of conventional right-univentricular vs biventricular pacing. The primary end-point was the 6-min walked distance, secondary end-points were peak oxygen uptake, quality-of-life, hospitalizations, patients' preferred study period and mortality.
  
  
  RESULTS
  Because of a higher than expected drop-out rate (42%), only 37 patients completed both crossover phases. In the intention-to-treat analysis, we did not observe a significant difference. However, in the patients with effective therapy the mean walked distance increased by 9.3% with biventricular pacing (374+/-108 vs 342+/-103 m in univentricular;P =0.05). Peak oxygen uptake increased by 13% (P=0.04). Hospitalizations decreased by 70% and 85% of the patients preferred the biventricular pacing period (P<0.001).
  
  
  CONCLUSIONS
  As compared with conventional VVIR pacing, effective biventricular pacing seems to improve exercise tolerance in NYHA class III heart failure patients with chronic atrial fibrillation and wide paced-QRS complexes. Further randomized controlled studies are required to definitively validate this therapy in such patients.
authors.affiliation: Département de Cardiologie, CHU, Rennes, France
authors.forename: C
authors.initials: C
authors.lastname: Leclercq
authors.forename: S
authors.initials: S
authors.lastname: Walker
authors.forename: C
authors.initials: C
authors.lastname: Linde
authors.forename: J
authors.initials: J
authors.lastname: Clementy
authors.forename: A J
authors.initials: AJ
authors.lastname: Marshall
authors.forename: P
authors.initials: P
authors.lastname: Ritter
authors.forename: P
authors.initials: P
authors.lastname: Djiane
authors.forename: P
authors.initials: P
authors.lastname: Mabo
authors.forename: T
authors.initials: T
authors.lastname: Levy
authors.forename: F
authors.initials: F
authors.lastname: Gadler
authors.forename: C
authors.initials: C
authors.lastname: Bailleul
authors.forename: J-C
authors.initials: JC
authors.lastname: Daubert
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D002908:Chronic Disease; D018592:Cross-Over Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000628:therapy*; D006801:Humans; D008297:Male; D016037:Single-Blind Method; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000628:therapy