title: Identification of "substrate fibrillators" and "trigger fibrillators" by pacemaker diagnostics.
abstract: BACKGROUND
  The population of patients likely to respond to selected pacing algorithms for maintenance of sinus rhythm is unknown.
  
  
  OBJECTIVE
  The purpose of this study was to identify patients with specific onset patterns of paroxysmal atrial fibrillation (AF).
  
  
  METHODS
  Dual-chamber pacemakers with advanced diagnostic functions were implanted in 112 patients with conventional indications for antibradycardia pacing and a history of paroxysmal AF. Pacemaker diagnostic data were analyzed after 97.5 +/- 40.9 days. According to the frequency of premature atrial contractions (PACs) during the 5 minutes before AF onset, patients were assigned to one of three groups: group A (high PAC activity), group B (moderate PAC activity), or group C (low PAC activity).
  
  
  RESULTS
  AF burden was lower in group A (4.6% +/- 2.4%) than group B (15.8% +/- 3.0%, P = .003) and group C (15.5% +/- 3.1%, P = .003). Fewer AF episodes occurred in group A (2.1 +/- 1.3 per day) than group B (3.8 +/- 1.2 per day, P = .006). Mean AF episode duration was shorter in group A (11.4 +/- 10.2 hours) than group C (41.4 +/- 27.5 hours, P = .03).
  
  
  CONCLUSIONS
  The coincidence of low PAC activity before AF onset, high AF burden, and extended arrhythmia episode duration appears to be the consequence of a high atrial substrate factor. In these "substrate fibrillators," the efficacy of pacing algorithms for maintenance of sinus rhythm may be limited. In contrast, "trigger fibrillators" exhibiting low AF burden despite high PAC incidence may represent the target population for specific PAC-suppressing pacing algorithms.
authors.affiliation: Department of Cardiology, University of Bonn, Germany. alexander.yang@web.de
authors.forename: Alexander
authors.initials: A
authors.lastname: Yang
authors.forename: Jaap
authors.initials: J
authors.lastname: Ruiter
authors.forename: Dietrich
authors.initials: D
authors.lastname: Pfeiffer
authors.forename: Bahman
authors.initials: B
authors.lastname: Esmailzadeh
authors.forename: Armin
authors.initials: A
authors.lastname: Welz
authors.forename: Marc
authors.initials: M
authors.lastname: Hochhäusler
authors.forename: Georg
authors.initials: G
authors.lastname: Nickenig
authors.forename: Berndt
authors.initials: B
authors.lastname: Lüderitz
authors.forename: Thorsten
authors.initials: T
authors.lastname: Lewalter
mesh_terms: D000368:Aged; D000465:Algorithms; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control; D018880:Atrial Premature Complexes / Q000175:diagnosis* / Q000503:physiopathology / Q000517:prevention & control; D002304:Cardiac Pacing, Artificial; D003936:Diagnosis, Computer-Assisted; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D012042:Registries; D013813:Therapy, Computer-Assisted; D013997:Time Factors