title: Atrial lead placement at the lower atrial septum: a potential strategy to reduce unnecessary right ventricular pacing.
abstract: OBJECTIVE
  Right ventricular (RV) pacing has been shown to be potentially detrimental to left ventricular function. In conventional dual-chamber pacing the position of the atrial lead could influence duration of the atrio-ventricular (AV) intervals, which is one of the variables that could be associated with an increased percentage of RV pacing. We wanted to see if lead placement at selected atrial septal sites could reduce AV intervals in patients receiving a dual-chamber pacemaker or implantable cardioverter defibrillator.
  
  
  RESULTS
  This was a prospective, acute, randomized single centre study that enrolled 57 patients. The atrial lead was placed in both the right atrial appendage (RAA) and the lower atrial septum (LAS) in each patient in random order. The P-wave durations, PR intervals, A sense-V sense (As-Vs), and A pace-V sense (Ap-Vs) intervals were measured at both atrial lead locations in each patient during device implant. The P-wave durations during sinus rhythm (SR), RAA pacing, and LAS pacing were 113 ± 19, 144 ± 27, and 84 ± 12 ms (RAA vs. LAS, P < 0.001), respectively. The PR intervals during SR, RAA pacing, and LAS pacing were 195 ± 47, 230 ± 61, and 167 ± 44 ms (RAA vs. LAS, P < 0.001), respectively. The As-Vs interval was 31% shorter in LAS pacing than in RAA pacing (134 ± 44 ms vs. 194 ± 52 ms, P < 0.001). The Ap-Vs interval was 24% shorter during LAS pacing than during RAA pacing (195 ± 45 ms vs. 257 ± 63 ms, P < 0.001).
  
  
  CONCLUSIONS
  When compared with RAA pacing, LAS pacing was associated with a shorter P wave duration, PR interval, As-Vs, and Ap-Vs intervals. The potential long-term impact of the strategy of pacing from LAS in reducing unnecessary RV pacing needs to be explored in future studies.
authors.affiliation: Trinity Medical Center, - West Campus, 2701 17th Street, Rock Island, Rock Island, IL 61201, USA. acosta@cvmedpc.com
authors.forename: Helbert
authors.initials: H
authors.lastname: Acosta
authors.forename: Lina Maria
authors.initials: LM
authors.lastname: Viafara
authors.forename: David
authors.initials: D
authors.lastname: Izquierdo
authors.forename: Vijayasimha R
authors.initials: VR
authors.lastname: Pothula
authors.forename: Julie
authors.initials: J
authors.lastname: Bear
authors.forename: Shravya
authors.initials: S
authors.lastname: Pothula
authors.forename: Cynthia
authors.initials: C
authors.lastname: Antonio-Drabeck
authors.forename: Kwangdeok
authors.initials: K
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000628:therapy*; D054087:Atrial Septum; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D016278:Ventricular Function, Right / Q000502:physiology*