title: Newly detected atrial fibrillation in patients with an implantable cardioverter-defibrillator is a strong risk marker of increased mortality.
abstract: BACKGROUND
  Atrial fibrillation (AF) has been associated with higher rates of all-cause mortality in patients with heart failure (HF). The risk of newly detected AF in patients receiving implantable cardioverter-defibrillator (ICD) therapy is unknown.
  
  
  METHODS
  Newly detected AF was evaluated in all patients enrolled in the Inhibition of Unnecessary RV Pacing with AV Search Hysteresis in ICDs (INTRINSIC RV) study. The relationships between AF and endpoints (total mortality, ICD shocks, and HF hospitalizations) were analyzed retrospectively with proportional-hazards models.
  
  
  RESULTS
  At 108 centers, 1530 patients meeting VITALITY AVT ICD indications were followed for 12 months. Of these, 1356 (89%) had no history of AF at the time of implant. Patients with a history of AF had a higher prevalence of HF (52% vs. 36%; P <.01) and had higher rates of HF hospitalization (hazard ratio [HR] 2.14 [1.29-3.54], P <.01), death (HR 2.22 [1.26-3.92], P <.01), and any ICD shock (HR 1.75 [1.19-2.58], P <.01) compared with those with no history. AF incidence during the first 3 months of implant was available in 1317 (86%; 1170 no AF, 147 history of AF) patients. New-onset AF during the first 3 months of implant (45 of 1170, 4%) was associated with a significant increased risk of death (HR 2.86 [1.02-8.05], P = .05) but not with inappropriate ICD shock (HR 2.43 [0.87-6.75], P = .09) or HF hospitalization (HR 1.17 [0.28-4.82], P = .83).
  
  
  CONCLUSIONS
  History of AF at the time of ICD implant identifies additional risk of HF and death. Newly detected AF is associated with significantly higher rates of death. The relationship between newly detected AF and inappropriate ICD shock or HF hospitalization is uncertain and requires further study.
authors.affiliation: Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA. Thomas.Bunch@imail.org
authors.forename: T Jared
authors.initials: TJ
authors.lastname: Bunch
authors.forename: John D
authors.initials: JD
authors.lastname: Day
authors.forename: Brian
authors.initials: B
authors.lastname: Olshansky
authors.forename: Kira Q
authors.initials: KQ
authors.lastname: Stolen
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Mullin
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D002423:Cause of Death / Q000639:trends; D017147:Defibrillators, Implantable; D018450:Disease Progression; D004554:Electric Countershock / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000453:epidemiology* / Q000628:therapy; D006760:Hospitalization / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D014481:United States / Q000453:epidemiology
chemical_list: D000319:Adrenergic beta-Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors