title: Right ventricular lead adjustment in cardiac resynchronization therapy and acute hemodynamic response: a pilot study.
abstract: OBJECTIVE
  Optimal left ventricular (LV) lead position has emerged as an important determinant of response after cardiac resynchronization therapy (CRT). Comparatively, strategy for right ventricular (RV) lead optimization remains uncertain.
  
  
  METHODS
  Three variations of RV lead position (apex, mid-septal, and high septal) were tested in seven consecutive patients. At each location, intra-procedural measurement of LV lead electrical delay (LVLED) was obtained during intrinsic rhythm and RV pacing (RV-LVLED). Simultaneous cardiac output assessment was performed using the LiDCO™ (lithium chloride indicator dilution) system. Final RV lead location was selected based on best-measured cardiac output. Clinical and echocardiographic outcomes were assessed at baseline and 6 months.
  
  
  RESULTS
  Adjustment of RV lead position after securing a LV lead site led to an incremental change of 30 ± 18 % (range, 7-52 %) in the cardiac index (CI). There was substantial variation in acute hemodynamic response (∆CI, 14 ± 13 %; range, 3-41 %) seen with pacing from each patient's worst to best RV lead position; no single RV lead position emerged as optimal across all patients. Paced RV-LVLED was not correlated with percent change in CI (r = 0.18; p = NS). LV ejection fraction (LVEF) increased significantly (28 ± 4 to 40 ± 8 %, p = 0.006) at 6 months. LVLED measured during intrinsic rhythm, but not during RV pacing, correlated with percent change in LVEF (r = 0.88, p = 0.02).
  
  
  CONCLUSIONS
  RV lead position adjustment can be used to enhance acute hemodynamic response during CRT. Measurement of paced RV-LVLED, however, does not reliably predict change in cardiac output.
authors.affiliation: Cardiac Arrhythmia Service, Harvard Medical School, Massachusetts General Hospital Heart Center, Boston, MA 02412, USA.
authors.forename: Prabhat
authors.initials: P
authors.lastname: Kumar
authors.forename: Gaurav A
authors.initials: GA
authors.lastname: Upadhyay
authors.forename: Christine
authors.initials: C
authors.lastname: Cavaliere-Ogus
authors.forename: E Kevin
authors.initials: EK
authors.lastname: Heist
authors.forename: Robert K
authors.initials: RK
authors.lastname: Altman
authors.forename: Neal A
authors.initials: NA
authors.lastname: Chatterjee
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Parks
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
mesh_terms: D000368:Aged; D002302:Cardiac Output; D058409:Cardiac Resynchronization Therapy Devices; D004567:Electrodes, Implanted; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000503:physiopathology* / Q000517:prevention & control*; D006352:Heart Ventricles / Q000601:surgery*; D006801:Humans; D008297:Male; D010865:Pilot Projects; D019919:Prosthesis Implantation / Q000379:methods; D013318:Stroke Volume; D016896:Treatment Outcome