title: Cardiac resynchronisation therapy: a randomised trial of factory or echocardiographic settings for optimum response.
abstract: BACKGROUND
  We aimed to assess whether echocardiographically-optimised atrioventricular (AV) and interventricular (VV) delay programming provided any additional benefit over standard settings following biventricular pacemaker implantation in patients with advanced heart failure.
  
  
  METHODS
  Paired data were collected on 22 patients (aged 67.5 ± 8.3 years, 16 male) with refractory heart failure, NYHA class III/IV symptoms, sinus rhythm, LBBB and a broad QRS complex >120 ms. All patients underwent implantation of a biventricular pacemaker and were randomised to eight weeks of factory pacing mode (Mode 1) or echocardiographically-guided pacing mode (Mode 2), followed by eight weeks in the alternate mode, in a randomised blinded crossover design.
  
  
  RESULTS
  Peak oxygen consumption, 6 min walk distance, NYHA class and quality of life scores improved after biventricular pacing, but no significant difference was found between the two modes, with the exception of peak oxygen consumption score (baseline: 14.8 ± 0.9, Mode 1: 14.6 ± 1.2, Mode 2: 16.1 ± 1.2 mL/kg/min), which was better in Mode 2 than Mode 1 (p 0.003).
  
  
  CONCLUSIONS
  Transthoracic echocardiographic optimisation of AV and VV delays following biventricular pacing may offer additional clinical benefit in an unselected group of patients when compared with factory settings.
authors.affiliation: Cardiology Department, The Heart Hospital, University College London Hospitals NHS Trust, 16-18 Westmoreland Street, London W1G 8PH, United Kingdom. Electronic address: vcobb@uclh.nhs.uk.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Cobb
authors.forename: Martin
authors.initials: M
authors.lastname: Thomas
authors.forename: Susan
authors.initials: S
authors.lastname: Ellery
authors.forename: Simon
authors.initials: S
authors.lastname: Jewell
authors.forename: Lorraine
authors.initials: L
authors.lastname: Lee
authors.forename: Rachael
authors.initials: R
authors.lastname: James
authors.forename: Sean
authors.initials: S
authors.lastname: O'Nunain
authors.forename: David
authors.initials: D
authors.lastname: Hildick-Smith
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D018592:Cross-Over Studies; D004452:Echocardiography / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: Biventricular pacing; Echocardiography; Heart failure; Non-responder; Optimisation