title: Inappropriate ICD therapy: does device configuration make a difference.
abstract: BACKGROUND
  Inappropriate implantable cardioverter defibrillator (ICD) therapy (IT) is a common complication in patients with ICD. IT is commonly triggered by supraventricular tachycardias (SVT). Dual chamber ICDs (D-ICDs) may distinguish SVT from ventricular tachycardia/ventricular fibrillation better than single chamber ICDs (S-ICDs) and may be associated with a smaller incidence of IT.
  
  
  METHODS
  We reviewed the charts of 386 patients who had an ICD implanted for an AHA class I indication. Intracardiac electrograms were used to classify shocks as either appropriate or inappropriate.
  
  
  RESULTS
  Of 295 patients with an S-ICD, 66 (22.3%) received IT, compared to 5 (5.4%) of 91 patients with a D-ICD. The likelihood of being event-free at 1, 2, 3, and 4 years was 96.1%, 96.1%, 96.1%, and 89% for patients with D-ICD and 80.7%, 72.7%, 69.6%, and 66.4%, respectively, for patients with S-ICD (P < 0.001). Multivariate analysis showed no significant association with age, sex, history of atrial fibrillation, history of hypertension, or ejection fraction. SVTs were the commonest cause of IT in our patients.
  
  
  CONCLUSIONS
  Patients with D-ICD are less likely to receive IT as compared to patients with S-ICD.
authors.affiliation: Thoracic and Cardiovascular Institute, Michigan State University, Lansing, Michigan 48910, USA.
authors.forename: Dwarakraj
authors.initials: D
authors.lastname: Soundarraj
authors.forename: Ranjan K
authors.initials: RK
authors.lastname: Thakur
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Gardiner
authors.forename: Atul
authors.initials: A
authors.lastname: Khasnis
authors.forename: Krit
authors.initials: K
authors.lastname: Jongnarangsin
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000453:epidemiology*; D015897:Comorbidity; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D018572:Disease-Free Survival; D004554:Electric Countershock / Q000706:statistics & numerical data*; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D006323:Heart Arrest / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D008297:Male; D008824:Michigan / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors