title: Atrial pacing site and atrioventricular conduction in patients paced for sinus node disease.
abstract: BACKGROUND
  Unnecessary ventricular pacing in sinus node disease (SND) must be avoided. To test the hypothesis that in SND, with or without 1st degree atrioventricular (AV) block, cumulative percent ventricular pacing (cum%VP) can be limited by low right atrial septal (LRAS) instead of right atrial appendage (RAA) pacing.
  
  
  METHODS
  We studied 102 dual-chamber pacemaker recipients with SND. The PQ interval on 12-lead electrocardiogram and the atrial paced to ventricular sensed interval (Ap-Vs) during LRAS and RAA pacing were measured and compared at implantation, 3 months and 1 year of follow-up. Group 1 included 62 patients with baseline PQ interval <200 milliseconds during LRAS (n = 28) versus RAA (n = 34) pacing. Group 2 included 40 patients with baseline PQ ≥200 milliseconds during LRAS (n = 20) versus RAA (n = 20) pacing. cum%VP were measured at 3 months and 1 year.
  
  
  RESULTS
  The characteristics and AV conduction properties were similar and the Ap-Vs interval was significantly shorter in the LRAS than in the RAA pacing group up to 1 year (193 ± 32 milliseconds vs. 220 ± 27 milliseconds in Group 1; P = 0.003, 222 ± 41 milliseconds vs. 281 ± 30 milliseconds in Group 2; P < 0.001). While cumulative percent atrial pacing was consistently similar, cum%VP was significantly smaller during LRAS than RAA pacing (1 ± 1% vs. 8 ± 18% in Group 1; P = 0.03, 7 ± 10% vs. 48 ± 38% in Group 2; P < 0.001). Similar observations were made with or without left atrial (LA) enlargement.
  
  
  CONCLUSIONS
  Compared with RAA, LRAS pacing showed shorter AV interval in SND patients with or without 1st degree AV block and LA enlargement. This beneficial effect persisted through 1-year follow-up, and decreased cum%VP significantly.
authors.affiliation: Second Department of Internal Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Watabe
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Abe
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Kohno
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Oginosawa
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Hayashi
authors.forename: Hisaharu
authors.initials: H
authors.lastname: Ohe
authors.forename: Masahito
authors.initials: M
authors.lastname: Tamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Otsuji
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria; D006329:Heart Conduction System / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012804:Sick Sinus Syndrome / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*
keywords: atrial pacing; atrioventricular conduction; atrioventricular pacing; low atrial septum; right atrial appendage; sinus node disease