title: A prospective comparison of echocardiography and device algorithms for atrioventricular and interventricular interval optimization in cardiac resynchronization therapy.
abstract: OBJECTIVE
  Echocardiographic optimization of atrioventricular (AV) and interventricular (VV) intervals in cardiac resynchronization therapy (CRT) is costly, time-consuming, and requires skill and expertise so is usually undertaken only in 'non-responder' patients. An algorithm in St Jude Medical CRT devices (QuickOpt) claims to optimize these settings automatically. The aim of this study was to compare the two optimization techniques.
  
  
  RESULTS
  Optimization of AV and VV intervals was performed a month after CRT device implantation in 26 patients with heart failure, first by echocardiography then by QuickOpt. The left ventricular outflow tract (LVOT) velocity-time integral (VTI) was measured after optimization by each method. Agreement between the optimization methods was assessed by the Bland-Altman analysis and correlation by Pearson's correlation coefficient. There was good correlation between the LVOT VTI following optimization by both methods (R2 = 0.77, P < 0.001). However, agreement between the two methods was poor, with 15 of 26 and 10 of 26 patients having a >20 ms difference in the optimal AV and VV interval values, respectively. Left ventricular outflow tract VTI was significantly better (22 of 26 patients; P < 0.001) in patients optimized by echocardiography than by QuickOpt.
  
  
  CONCLUSIONS
  There is a poor agreement in optimal AV and VV intervals determined by echocardiography and QuickOpt, with echocardiographic optimization giving a superior haemodynamic outcome.
authors.affiliation: Department of Cardiology, St Bartholomew's Hospital, Barts and the London NHS Trust, Dominion House, 60 Bartholomew Close, West Smithfield, EC1A 7BE London, UK.
authors.forename: Ravindu
authors.initials: R
authors.lastname: Kamdar
authors.forename: Evelyn
authors.initials: E
authors.lastname: Frain
authors.forename: Fiona
authors.initials: F
authors.lastname: Warburton
authors.forename: Laura
authors.initials: L
authors.lastname: Richmond
authors.forename: Victoria
authors.initials: V
authors.lastname: Mullan
authors.forename: Thomas
authors.initials: T
authors.lastname: Berriman
authors.forename: Glyn
authors.initials: G
authors.lastname: Thomas
authors.forename: Joanna
authors.initials: J
authors.lastname: Tenkorang
authors.forename: Mehul
authors.initials: M
authors.lastname: Dhinoja
authors.forename: Mark
authors.initials: M
authors.lastname: Earley
authors.forename: Simon
authors.initials: S
authors.lastname: Sporton
authors.forename: Richard
authors.initials: R
authors.lastname: Schilling
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004452:Echocardiography / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome