title: Atrial therapies reduce atrial arrhythmia burden in defibrillator patients.
abstract: BACKGROUND
  Approximately 25% of patients who receive an implantable cardioverter-defibrillator (ICD) to treat ventricular tachyarrhythmias have documented atrial tachyarrhythmias before implantation. This study assessed the ability of device-based prevention and termination therapies to reduce the burden of spontaneous atrial tachyarrhythmias.
  
  
  RESULTS
  Patients with a standard indication for the implantation of an ICD and 2 episodes of atrial tachyarrhythmias in the preceding year received a dual-chamber ICD (Medtronic 7250 Jewel AF) that uses pacing and shock therapies for prevention and/or termination of atrial tachyarrhythmias. In a multicenter trial, patients were randomized to 3-month periods with atrial therapies "on" or "off" and subsequently crossed over. Analysis was performed on the 52 of 269 patients who had episodes of atrial tachyarrhythmia and had >/=30 days of follow-up with atrial therapies on and off. The atrial therapies resulted in a reduction of atrial tachyarrhythmia burden from a mean of 58.5 to 7.8 h/mo. A paired analysis (Wilcoxon signed-rank test) showed that the median difference in burden (1.1 h/mo) was highly significant (P=0.007). When the subgroup of 41 patients treated only with atrial pacing therapies was analyzed, the reduction in burden persisted (P=0.01).
  
  
  CONCLUSIONS
  In this study, patients with a standard ICD indication and atrial tachyarrhythmias had a significant reduction in atrial tachyarrhythmia burden with use of atrial pacing and shock therapies.
authors.affiliation: Mayo Clinic, Rochester, MN 55905, USA. pfriedman@ mayo.edu
authors.forename: P A
authors.initials: PA
authors.lastname: Friedman
authors.forename: B
authors.initials: B
authors.lastname: Dijkman
authors.forename: E N
authors.initials: EN
authors.lastname: Warman
authors.forename: H A
authors.initials: HA
authors.lastname: Xia
authors.forename: R
authors.initials: R
authors.lastname: Mehra
authors.forename: M S
authors.initials: MS
authors.lastname: Stanton
authors.forename: S C
authors.initials: SC
authors.lastname: Hammill
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome