title: Right ventricular septal pacing: a comparative study of outflow tract and mid ventricular sites.
abstract: BACKGROUND
  Prolonged right ventricle (RV) apical pacing is associated with left ventricle (LV) dysfunction due to dysynchronous ventricular activation and contraction. Alternative RV pacing sites with a narrower QRS compared to RV pacing might reflect a more physiological and synchronous LV activation. The purpose of this study was to compare the QRS morphology, duration, and suitability of RV outflow tract (RVOT) septal and mid-RV septal pacing.
  
  
  METHODS
  Seventeen consecutive patients with indication for dual-chamber pacing were enrolled in the study. Two standard 58-cm active fixation leads were passed to the RV and positioned in the RVOT septum and mid-RV septum using a commercially available septal stylet (model 4140, St. Jude Medical, St. Paul, MN, USA). QRS duration, morphology, and pacing parameters were compared at the two sites. The RV lead with less-satisfactory electrical parameters was withdrawn and deployed in the right atrium.
  
  
  RESULTS
  Successful positioning of the pacing leads at the RVOT septum and mid-RV septum was achieved in 15 patients (88.2%). There were no significant differences in the mean stimulation threshold, R-wave sensing, and lead impedance between the two sites. The QRS duration in the RVOT septum was 151 ± 14 ms and in the mid-RV septum 145 ± 13 ms (P = 0.150).
  
  
  CONCLUSIONS
  This prospective observational study shows that septal pacing can be reliably achieved both in the RVOT and mid-RV with active fixation leads using a specifically shaped stylet. There are no preferences in regard to acute lead performance or paced QRS duration with either position.
authors.affiliation: Department of Cardiology, Royal Melbourne Hospital, Victoria 3050, Melbourne, Australia.
authors.forename: Raphael
authors.initials: R
authors.lastname: Rosso
authors.forename: Caroline
authors.initials: C
authors.lastname: Medi
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Teh
authors.forename: Thuy To
authors.initials: TT
authors.lastname: Hung
authors.forename: Alexander
authors.initials: A
authors.lastname: Feldman
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Lee
authors.forename: Harry G
authors.initials: HG
authors.lastname: Mond
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000503:physiopathology / Q000628:therapy*; D002304:Cardiac Pacing, Artificial; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012804:Sick Sinus Syndrome / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D054088:Ventricular Septum / Q000503:physiopathology*