title: The impact of the right ventricular lead position on response to cardiac resynchronization therapy.
abstract: BACKGROUND
  Left ventricular (LV) lead placement to the latest contracting area (concordant LV lead) is associated with better response to cardiac resynchronization therapy (CRT) compared to a discordant LV lead. However, the effect of the right ventricular (RV) lead site on CRT response is unclear. We investigated the relationship of the RV and LV lead positions on CRT response.
  
  
  METHODS
  In 131 CRT patients, the LV lead was positioned preferentially in a lateral or posterolateral vein and the RV lead to either the RV septum (RVS, n = 55) or RV apex (RVA, n = 76). The latest site of contraction was determined with two-dimensional speckle tracking radial strain imaging and patients had a concordant LV lead position if pacing the latest segment, and discordant if not. Response was defined as ≥15% reduction in LV end systolic volume (LVESV) at 6-month follow-up.
  
  
  RESULTS
  There were no significant differences in mean reduction of LVESV at follow-up (RVS vs RVA: -23.3 ± 16% vs 22.1 ± 18%, P = 0.70) or rate of responders (58.2% vs 57.9%, P = 0.97) between the two groups. In patients with a concordant LV lead (n = 71), the response rate was significantly higher than those with a discordant lead (76.1% vs 36.7%, P < 0.001). There were no differences in outcomes in patients with a concordant or discordant LV lead according to the RV lead location.
  
  
  CONCLUSIONS
  The extent of LV reverse remodeling following CRT is not related to the RV lead position, but is significantly higher in patients with a concordant LV lead.
authors.affiliation: Addenbrooke's Hospital, Cambridge, UK. fzkhan@doctors.org.uk
authors.forename: Fakhar Z
authors.initials: FZ
authors.lastname: Khan
authors.forename: Pegah
authors.initials: P
authors.lastname: Salahshouri
authors.forename: Rudy
authors.initials: R
authors.lastname: Duehmke
authors.forename: Philip A
authors.initials: PA
authors.lastname: Read
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Pugh
authors.forename: Maros
authors.initials: M
authors.lastname: Elsik
authors.forename: David
authors.initials: D
authors.lastname: Begley
authors.forename: Simon P
authors.initials: SP
authors.lastname: Fynn
authors.forename: David P
authors.initials: DP
authors.lastname: Dutka
authors.forename: Munmohan S
authors.initials: MS
authors.lastname: Virdee
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods / Q000706:statistics & numerical data; D058409:Cardiac Resynchronization Therapy Devices / Q000706:statistics & numerical data*; D004567:Electrodes, Implanted; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control*; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D015995:Prevalence; D019919:Prosthesis Implantation / Q000379:methods / Q000706:statistics & numerical data*; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology