title: Medium-term effects of septal and apical pacing in pacemaker-dependent patients: a double-blind prospective randomized study.
abstract: BACKGROUND
  Pacing the right ventricle is established practice, but there remains controversy as to the optimal site to preserve hemodynamic function.
  
  
  OBJECTIVE
  To evaluate clinical and hemodynamic differences between apical and septal pacing in pacemaker-dependent patients.
  
  
  METHODS
  Patients receiving their first pacemaker for advanced atrioventricular block, with the atria in sinus rhythm, were randomized to receive apical (Group A) or septal (Group S) ventricular leads. After implant, with the device programmed VVI 70 beats/min fixed rate, patients underwent a 6-minute walk test and a transthoracic echocardiogram. Then, DDDR was programmed at nominal settings. The same tests were performed at 6 months and 12 months follow-up. If ventricular pacing was less than 98%, the patient was excluded.
  
  
  RESULTS
  A total of 142 patients were included in the study. During the study year, 71 (50%) were excluded for not fulfilling the condition of 98% ventricular pacing. Groups A and S had 34 and 37 patients, respectively. Age and gender were similar in the groups. At implant, QRS duration was significantly greater in Group A (158 ms) than Group S (146 ms; P = 0.018), and the QRS axis was different: -74.5° in Group A and 1° in Group S (P < 0.001). At 1 year, the 6-minute walk improved significantly in both groups: Group A 15% (P = 0.048) and Group S 24% (P = 0.001). Left ventricular ejection fraction (LVEF) increased from 0.57 to 0.61 (P = 0.008) in Group S, without significant change in Group A.
  
  
  CONCLUSIONS
  After 1 year, pacemaker-dependent patients with septal ventricular leads have better clinical and functional (LVEF) outcome.
authors.affiliation: Arrhythmia Laboratory of the Universidad Nacional Autónoma de México (UNAM) en Hospital General de México, Mexico City, Medico.
authors.forename: Luis
authors.initials: L
authors.lastname: Molina
authors.forename: Richard
authors.initials: R
authors.lastname: Sutton
authors.forename: William
authors.initials: W
authors.lastname: Gandoy
authors.forename: Nicolás
authors.initials: N
authors.lastname: Reyes
authors.forename: Susano
authors.initials: S
authors.lastname: Lara
authors.forename: Froylán
authors.initials: F
authors.lastname: Limón
authors.forename: Susana
authors.initials: S
authors.lastname: Gómez
authors.forename: Consuelo
authors.initials: C
authors.lastname: Orihuela
authors.forename: Latife
authors.initials: L
authors.lastname: Salame
authors.forename: Gabriela
authors.initials: G
authors.lastname: Moreno
mesh_terms: D054537:Atrioventricular Block / Q000175:diagnosis* / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006346:Heart Septum; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: 6-minute walk; apical pacing; echocardiography; pacemaker dependency; right ventricular pacing; septal pacing