title: Randomized prospective trial of atrioventricular delay programming for cardiac resynchronization therapy.
abstract: OBJECTIVE
  The purpose of this study was to determine if AV delay optimization with continuous-wave Doppler aortic velocity-time integral (VTI) is clinically superior to an empiric program in patients treated with cardiac resynchronization therapy (CRT) for severe heart failure.
  
  
  BACKGROUND
  The impact of AV delay programming on clinical outcomes associated with CRT is unknown.
  
  
  METHODS
  A randomized, prospective, single-blind clinical trial was performed to compare two methods of AV delay programming in 40 patients with severe heart failure referred for CRT. Patients were randomized to either an optimized AV delay determined by Doppler echocardiography (group 1, n = 20) or an empiric AV delay of 120 ms (group 2, n = 20) with both groups programmed in the atriosynchronous biventricular pacing (VDD) mode. Optimal AV delay was defined as the AV delay that yielded the largest aortic VTI at one of eight tested AV intervals (between 60 and 200 ms). New York Heart Association (NYHA) functional classification and quality-of-life (QOL) score were compared 3 months after randomization.
  
  
  RESULTS
  Immediately after CRT initiation with AV delay programming, VTI improved by 4.0 +/- 1.7 cm vs 1.8 +/- 3.6 cm (P < .02), and ejection fraction (EF) increased by 7.8 +/- 6.2% vs 3.4 +/- 4.4% (P < .02) in group 1 vs group 2, respectively. After 3 months, NYHA classification improved by 1.0 +/- 0.5 vs 0.4 +/- 0.6 class points (P < .01), and QOL score improved by 23 +/- 13 versus 13 +/- 11 points (P < .03) for group 1 vs group 2, respectively.
  
  
  CONCLUSIONS
  Echocardiography-guided AV delay optimization using the aortic Doppler VTI improves clinical outcomes at 3 months compared to an empiric AV delay program of 120 ms.
authors.affiliation: Cardiovascular Division, Washington University, School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Navinder S
authors.initials: NS
authors.lastname: Sawhney
authors.forename: Alan D
authors.initials: AD
authors.lastname: Waggoner
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Garhwal
authors.forename: Mohit K
authors.initials: MK
authors.lastname: Chawla
authors.forename: Judy
authors.initials: J
authors.lastname: Osborn
authors.forename: Mitchell N
authors.initials: MN
authors.lastname: Faddis
mesh_terms: D001283:Atrioventricular Node / Q000000981:diagnostic imaging / Q000502:physiology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000145:classification / Q000628:therapy*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D016037:Single-Blind Method; D013318:Stroke Volume / Q000502:physiology; D016896:Treatment Outcome