title: The impact of atrial prevention and termination therapies on atrial tachyarrhythmia burden in patients receiving a dual-chamber defibrillator for ventricular arrhythmias.
abstract: BACKGROUND
  This prospective, multicenter, randomized trial evaluated the effects of atrial prevention and termination therapies on atrial tachyarrhythmia (ATA) burden in patients with a standard indication for an implantable cardioverter defibrillator (ICD).
  
  
  METHODS
  A Jewel AF or GEM III AT ICD was implanted in 451 patients. At 1-month post-implant, patients were randomized to atrial prevention and termination therapies ON ( n = 199) or OFF ( n = 206) and followed for 6 additional months. Automatic atrial shocks were enabled in only 14% of the ON group. The follow-up time after randomization was 6.9 +/- 2.4 months ON versus 6.8 +/- 2.3 months OFF.
  
  
  RESULTS
  There were 126/405 (31.1%) patients who had AT/AF episodes during follow-up. Only four patients received a shock to treat ATA's during follow-up. The median ATA burden was 0 hours/month in both the ON and OFF groups ( P = 0.40). The mean ATA burden was 4.3 +/- 20.0 hours/month ON versus 9.0 +/- 50.0 hours/month OFF ( P = 0.11). In a subgroup of 192 patients with a history of ATA's, the median burden was 0 hours/month in the both groups ( P = 0.23). However, the mean burden in this subgroup was 7.6 +/- 27.1 hours/month ON versus 19.2 +/- 73.7 hours/month OFF ( P = 0.056).
  
  
  CONCLUSIONS
  In patients receiving an ICD for ventricular arrhythmias, no significant change in ATA burden was observed when atrial prevention and termination therapies were enabled. This may have been due to the low ATA burden in this population. In a subgroup of patients with history of ATA's, there was a trend towards a reduction in mean burden.
authors.affiliation: Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA. friedman.paul@mayo.edu
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: John H
authors.initials: JH
authors.lastname: Ip
authors.forename: Mohammad
authors.initials: M
authors.lastname: Jazayeri
authors.forename: John H
authors.initials: JH
authors.lastname: Lobban
authors.forename: Brian
authors.initials: B
authors.lastname: Olshansky
authors.forename: Duo
authors.initials: D
authors.lastname: Zhou
authors.forename: Tracy
authors.initials: T
authors.lastname: Knowles
authors.forename: David E
authors.initials: DE
authors.lastname: Euler
mesh_terms: D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D001282:Atrial Flutter / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial; D016009:Chi-Square Distribution; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents