title: Right ventricular apical lead position is associated with prolonged signal-averaged P-wave duration.
abstract: OBJECTIVE
  The study aimed to determine if right ventricular apical pacing is associated with adverse change in atrial substrate compared with right ventricular septal pacing.
  
  
  METHODS
  Patients with septal leads and dual-chamber devices with more than 3 months of follow-up and 70% or higher cumulative percentage of ventricular pacing were compared with a matched group of apically implanted leads with a cumulative percentage ventricular pacing of 70% or higher. Device parameters were recorded, and high-resolution recordings were obtained for signal-averaged P-wave (SAPW) analysis. Previously obtained SAPW recordings taken from 49 healthy patients and 73 patients with paroxysmal atrial fibrillation were used as negative and positive controls, respectively.
  
  
  RESULTS
  Ten patients with septal leads (mean age, 71.9 +/- 12.1 years; mean months implanted, 10.5 +/- 3.2 months) and 9 patients with apical leads (mean age, 71.9 +/- 5.7 years; mean months implanted, 11.4 +/- 6.4 months) were enrolled. The SAPW duration was longer in the apical cohort compared with the septal cohort (144.8 +/- 6.9 and 133.0 +/- 5.5 milliseconds, respectively; P = .001), whereas there was no significant difference between septal and normal cohorts (133.0 +/- 5.5 and 129.3 +/- 7.1 milliseconds, respectively; P = .08).
  
  
  CONCLUSIONS
  Apical pacing is associated with prolonged P-wave duration relative to septal pacing and controls: this may manifest as increased risk of atrial tachycardias and presents a potentially novel benefit of septal pacing.
authors.affiliation: Arrhythmia Service, Queen's University, Kingston General Hospital, Kingston, Ontario, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Maraschiello
authors.forename: Damian P
authors.initials: DP
authors.lastname: Redfearn
authors.forename: Adrian M
authors.initials: AM
authors.lastname: Baranchuk
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Simpson
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D006346:Heart Septum / Q000601:surgery*; D006352:Heart Ventricles / Q000601:surgery*; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D016896:Treatment Outcome