title: Effectiveness of atrial antitachycardia pacing in the treatment of paroxysmal atrial fibrillation in patients with pacemakers.
abstract: BACKGROUND
  The aim of this study was to assess the effectiveness of atrial antitachycardia pacing (ATP) in the conversion of atrial tachyarrhythmia episodes, and its impact in reducing arrhythmic burden.
  
  
  METHODS
  We performed a retrospective study in the pacing laboratory of a district hospital of 57 consecutive patients implanted with a dual chamber pacemaker, capable of performing atrial antitachycardia pacing, between 2005 and 2010. The patients were divided into two groups: ATP_ON (n=24) and ATP_OFF (n=33). The follow-up period was 15 months, with data being collected at three follow-up consultations: the first at three months after implantation, the second at nine months and the last at 15 months. In this period, there were 12 428 ATP therapies of atrial tachyarrhythmias.
  
  
  RESULTS
  Although there were no statistically significant differences, there was a trend in favor of the ATP_ON group, the increase in arrhythmic burden being less marked in this group. The mean percentage of ventricular apical pacing was also significantly lower in this group, which was associated with a marginally significant reduction in arrhythmic burden (p=0.06). There was a significant positive correlation between changes in the percentage of ventricular pacing and changes in arrhythmic burden (r=0.417, p=0.02).
  
  
  CONCLUSIONS
  Atrial antitachycardia pacing converted 59.7% of episodes of atrial arrhythmia, but did not significantly reduce arrhythmic burden. There was a significant positive correlation between changes in the percentage of ventricular pacing and changes in arrhythmic burden.
authors.affiliation: Laboratório de Pacing, Serviço de Cardiologia, Hospital de Santarém, EPE, Santarém, Portugal. Electronic address: ramsilv@gmail.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Silva
authors.affiliation: Departamento de Cardiopneumologia, Escola Superior de Tecnologia da Saúde de Coimbra, Coimbra, Portugal; Departamento de Cardiopneumologia, Universidade Metodista de Angola, Luanda, Angola.
authors.forename: Telmo
authors.initials: T
authors.lastname: Pereira
authors.affiliation: Laboratório de Pacing, Serviço de Cardiologia, Hospital de Santarém, EPE, Santarém, Portugal.
authors.forename: Vitor
authors.initials: V
authors.lastname: Martins
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000628:therapy*; D002304:Cardiac Pacing, Artificial; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Arrhythmic burden; Atrial antitachycardia pacing; Atrial fibrillation; Carga arrítmica; Fibrilhação auricular; Pacing auricular antitaquicardia; Pacing ventricular; Ventricular pacing