title: Combined efficacy of atrial septal lead placement and atrial pacing algorithms for prevention of paroxysmal atrial tachyarrhythmia.
abstract: BACKGROUND
  The combined role of atrial septal lead location and atrial pacing algorithms in the prevention of atrial tachyarrhythmias (AT/AF), including both atrial fibrillation and flutter, is unknown. We tested the hypothesis that atrial prevention pacing algorithms could decrease AT/AF frequency in patients with atrial septal leads, bradycardia, and paroxysmal AT/AF.
  
  
  RESULTS
  A total of 298 patients (age 70 +/- 10 years; 61% male) from 35 centers were implanted with a DDDRP pacing system including three AT/AF prevention pacing algorithms. Lead site was randomized at implant to right atrial septal or nonseptal. Patients were randomized 1 month postimplant to AT/AF prevention ON or OFF for 3 months and then crossed over for 3 months. Patients logged symptomatic AT/AF episodes via a manual activator. Prevention efficacy was evaluated based on intention-to-treat in 277 patients (138 septal) with complete follow-up. No changes in device-recorded AT/AF frequency or burden were observed with algorithms OFF versus ON or between patients randomized to septal versus nonseptal lead location. Analysis of other secondary outcomes revealed that AT/AF prevention pacing resulted in decreased atrial premature contractions in both the septal (1.9 [0.2-8.7] vs 3.3 [0.3-10.6]x 103/day; P < 0.01) and nonseptal groups (0.9 [0.2-3.3] vs 1.3 [0.3-5.5]x 103/day; P < 0.001). Patients with septal leads had fewer symptomatic AT/AF episodes ON versus OFF (1.4 +/- 3.0 vs 2.5 +/- 5.2/month, P = 0.01).
  
  
  CONCLUSIONS
  The combination of three atrial prevention pacing algorithms did not decrease device classified atrial tachyarrhythmia frequency or burden during a 3-month cross-over period in bradycardic patients and septal or nonseptal atrial pacing leads. Prevention pacing was associated with decreased frequency of premature atrial contractions and with decreased symptomatic atrial tachyarrhythmia frequency in patients with atrial septal leads.
authors.affiliation: Institute of Internal Medicine and Cardiology, University of Florence, Viale Morgagni 85, 50134 Florence, Italy. electrofisiologia@dac.unifi.it
authors.forename: Luigi
authors.initials: L
authors.lastname: Padeletti
authors.forename: Helmut
authors.initials: H
authors.lastname: Pürerfellner
authors.forename: Stuart W
authors.initials: SW
authors.lastname: Adler
authors.forename: Theodore J
authors.initials: TJ
authors.lastname: Waller
authors.forename: Mark
authors.initials: M
authors.lastname: Harvey
authors.forename: Lewis
authors.initials: L
authors.lastname: Horvitz
authors.forename: Reece
authors.initials: R
authors.lastname: Holbrook
authors.forename: Kitty
authors.initials: K
authors.lastname: Kempen
authors.forename: Andrew
authors.initials: A
authors.lastname: Mugglin
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Hettrick
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D016037:Single-Blind Method; D013610:Tachycardia / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome