title: Comparison of a non-invasive arterial pulse contour technique and echo Doppler aorta velocity-time integral on stroke volume changes in optimization of cardiac resynchronization therapy.
abstract: OBJECTIVE
  We investigated the accuracy and feasibility of a non-invasive arterial pulse contour technique for continuous measurement of stroke volume (SV) in optimization of atrioventricular (AV) delay in cardiac resynchronization therapy (CRT), by comparing SV changes assessed by Nexfin CO-Trek® (Nexfin) and echo Doppler aortic velocity-time integral (VTIao). Furthermore, we investigated whether AV-delay optimization increases the effect of CRT when compared with a default AV delay (120 ms).
  
  
  RESULTS
  In 23 CRT patients, biventricular pacing (BiVP) was applied at various AV delays, while recording 10 beats preceding BiVP (baseline) and the first 10 BiVP beats, for both methods in parallel. Agreement between Nexfin and VTIao measurements was evaluated (Bland-Altman) on beat-to-beat changes in SV, as well as on effects of BiVP (averaged over 8 beats) at various AV delays. Individual optimal AV delays, for Nexfin (AVopt-n) and VTIao (AVopt-ao), were derived from the second-order polynomial fitted to the effect measurements of 20 patients. In 252 episodes assessed, the difference between measurements (= Nexfin - VTIao) was -0.6 ± 8.1% for beat-to-beat SV changes and -1.3 ± 7.3% for effects of BiVP. Optimal AV delays for Nexfin were well related to AVopt-ao (R(2) = 0.69). The effect (%) of BiVP at the optimal AV delay was significantly larger than at the default AV delay: median difference (range) being +6.3% (0.1-14.4%; P < 0.001) for VTIao and +4.7% (0.0-14.0%; P < 0.001) for Nexfin.
  
  
  CONCLUSIONS
  Individual AV optimization increases the effect of CRT. Nexfin is a promising tool in individual CRT optimization, as Nexfin agrees with VTIao on measuring beat-to-beat SV changes and on assessing relative effects of BiVP on SV at various AV delays.
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, PO Box 616, NL-6200 MD Maastricht, The Netherlands. i.vangeldorp@fys.unimaas.nl
authors.forename: Irene E
authors.initials: IE
authors.lastname: van Geldorp
authors.forename: Tammo
authors.initials: T
authors.lastname: Delhaas
authors.forename: Ben
authors.initials: B
authors.lastname: Hermans
authors.forename: Kevin
authors.initials: K
authors.lastname: Vernooy
authors.forename: Bernard
authors.initials: B
authors.lastname: Broers
authors.forename: Julija
authors.initials: J
authors.lastname: Klimusina
authors.forename: Francois
authors.initials: F
authors.lastname: Regoli
authors.forename: Francesco F
authors.initials: FF
authors.lastname: Faletra
authors.forename: Tiziano
authors.initials: T
authors.lastname: Moccetti
authors.forename: Bart
authors.initials: B
authors.lastname: Gerritse
authors.forename: Richard
authors.initials: R
authors.lastname: Cornelussen
authors.forename: Jos J
authors.initials: JJ
authors.lastname: Settels
authors.forename: Harry J G M
authors.initials: HJ
authors.lastname: Crijns
authors.forename: Angelo
authors.initials: A
authors.lastname: Auricchio
authors.forename: Frits W
authors.initials: FW
authors.lastname: Prinzen
mesh_terms: D001011:Aorta / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D058406:Cardiac Resynchronization Therapy; D017147:Defibrillators, Implantable; D015150:Echocardiography, Doppler / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D011674:Pulse / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology*; D013997:Time Factors