title: Atrial tachyarrhythmias temporally precede fluid accumulation in implantable device patients.
abstract: BACKGROUND
  The complex relationship between heart failure and atrial tachyarrhythmias (AT/atrial fibrillation [AF]) is not well understood. We examined the temporal association between changes in intrathoracic impedance, suggesting thoracic fluid accumulation, and AT/AF occurrence in cardiac resynchronization therapy-defibrillator and implantable cardioverter defibrillator (ICD) patients.
  
  
  METHODS
  A retrospective analysis was conducted on stored implantable device data to identify patients with automatic monitoring of daily AT/AF burden and intrathoracic impedance. Daily population trends in AT/AF burden before and after a fluid index threshold crossing (FIC) were determined.
  
  
  RESULTS
  A total of 73,018 patients (68 ± 12 years, 51% ICD, 75% male) were evaluated over 18.6 ± 11.5 months. Kaplan-Meier analysis indicated a significantly higher probability of FIC events in the first month following the onset of persistent AT/AF when compared to a matched group without persistent AT/AF (hazard ratio [HR] 1.65, 95% confidence interval [CI] [1.58, 1.72], P < 0.001). Conversely, patients were significantly more likely to experience an episode of persistent AF in the first month after the FIC event (HR 1.32, 95% CI [1.08, 1.63], P = 0.008). The probability of a fluid index crossing within 30 days of the onset of persistent AT/AF was significantly lower in a subgroup of patients with adequate rate control (35.8% [34.3-37.4%] vs 42.0% [39.6-44.6%]; HR 1.24 [1.13-1.36]).
  
  
  CONCLUSIONS
  Thoracic fluid accumulation, as indicated by decreasing intrathoracic impedance, was more likely to occur immediately after the onset of persistent AT/AF, especially in the presence of inadequate rate control. Likewise, the onset of persistent AT/AF was more likely following a decrease in intrathoracic impedance.
authors.affiliation: Department of Cardiology, Cooper University Hospital, Cooper Medical School at Rowan University, Camden, New Jersey.
authors.forename: John A
authors.initials: JA
authors.lastname: Andriulli
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Moore
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Hettrick
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Ousdigian
authors.forename: James
authors.initials: J
authors.lastname: Johnson
authors.forename: Steven M
authors.initials: SM
authors.lastname: Markowitz
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology* / Q000517:prevention & control*; D058409:Cardiac Resynchronization Therapy Devices / Q000706:statistics & numerical data*; D002307:Cardiography, Impedance / Q000706:statistics & numerical data; D015984:Causality; D015897:Comorbidity; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D005260:Female; D006333:Heart Failure; D006801:Humans; D015994:Incidence; D008297:Male; D010996:Pleural Effusion / Q000175:diagnosis* / Q000453:epidemiology*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014481:United States / Q000453:epidemiology
keywords: CRT; atrial fibrillation; congestive heart failure; defibrillation - ICD