title: Pre-ejection period by radial artery tonometry supplements echo Doppler findings during biventricular pacemaker optimization.
abstract: BACKGROUND
  Biventricular (Biv) pacemaker echo optimization has been shown to improve cardiac output however is not routinely used due to its complexity. We investigated the role of a simple method involving computerized pre-ejection time (PEP) assessment by radial artery tonometry in guiding Biv pacemaker optimization.
  
  
  METHODS
  Blinded echo and radial artery tonometry were performed simultaneously in 37 patients, age 69.1 ± 12.8 years, left ventricular (LV) ejection fraction (EF) 33 ± 10%, during Biv pacemaker optimization. Effect of optimization on echo derived velocity time integral (VTI), ejection time (ET), myocardial performance index (MPI), radial artery tonometry derived PEP and echo-radial artery tonometry derived PEP/VTI and PEP/ET indices was evaluated.
  
  
  RESULTS
  Significant improvement post optimization was achieved in LV ET (286.9 ± 37.3 to 299 ± 34.6 ms, p < 0.001), LV VTI (15.9 ± 4.8 cm to 18.4 ± 5.1 cm, p < 0.001) and MPI (0.57 ± 0.2 to 0.45 ± 0.13, p < 0.001) and in PEP (246.7 ± 36.1 ms to 234.7 ± 35.5 ms, p = 0.003), PEP/ET (0.88 ± 0.21 to 0.79 ± 0.17, p < 0.001), and PEP/VTI (17.3 ± 7 to 13.78 ± 4.7, p < 0.001). The correlation between comprehensive echo Doppler and radial artery tonometry-PEP guided optimal atrioventricular delay (AVD) and optimal interventricular delay (VVD) was 0.75 (p < 0.001) and 0.69 (p < 0.001) respectively. In 29 patients with follow up assessment, New York Heart Association (NYHA) class reduced from 2.5 ± 0.8 to 2.0 ± 0.9 (p = 0.004) at 1.8 ± 1.4 months.
  
  
  CONCLUSIONS
  An acute shortening of PEP by radial artery tonometry occurs post Biv pacemaker optimization and correlates with improvement in hemodynamics by echo Doppler and may provide a cost-efficient approach to assist with Biv pacemaker echo optimization.
authors.affiliation: Non Invasive Diagnostic Services and Echocardiography Laboratory, Cardiovascular and Thoracic Institute, Keck School of Medicine, University of Southern California, Los Angeles, USA.
authors.forename: Nima
authors.initials: N
authors.lastname: Taha
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Reza
authors.initials: R
authors.lastname: Rafie
authors.forename: Rupesh
authors.initials: R
authors.lastname: Ranjan
authors.forename: Salima
authors.initials: S
authors.lastname: Qamruddin
authors.forename: Tasneem Z
authors.initials: TZ
authors.lastname: Naqvi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial / Q000379:methods* / Q000592:standards; D015150:Echocardiography, Doppler / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000628:therapy*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D011673:Pulsatile Flow / Q000502:physiology; D017534:Radial Artery / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology*; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods