title: Mechanisms of inappropriate defibrillator therapy in a modern cohort of remotely monitored patients.
abstract: BACKGROUND
  Defibrillator (ICD) technology and monitoring are evolving rapidly. We investigated the mechanisms of inappropriate ICD therapies in a modern cohort of patients followed at our institution via remote monitoring.
  
  
  METHODS
  From September 2009 to March 2011, a total of 2,050 ICD patients (19,600 patient-months) were remotely followed. All events (shocks and antitachycardia pacing) were adjudicated by arrhythmia specialists.
  
  
  RESULTS
  A total of 249 patients received ICD therapy (34% inappropriate therapy). Inappropriate ICD shocks affected 33 (1.6%) patients. There were a total of 249 inappropriate episodes in 85 patients. Supraventricular tachycardia (SVT) with 1:1 atrioventricular association was the predominant mechanism accounting for 133 episodes in 50 patients, followed by atrial fibrillation (97 episodes in 27 patients). T-wave oversensing (16 episodes in five patients), electromagnetic interference (two episodes in two patients), and ectopic beats (one episode in one patient) accounted for a small proportion of events. There were 35 arrhythmic episodes in five patients that could not be classified, all in patients with single-chamber devices. There were no differences in these results by device manufacturer.
  
  
  CONCLUSIONS
  Despite many technological advances, inappropriate ICD shocks still occur but at very low rates and SVT with 1:1 atrioventricular association represents their most common mechanism.
authors: University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
authors: Hemal
authors: H
authors: Shah
authors: Ure
authors: U
authors: Mezu
authors: Divyang
authors: D
authors: Patel
authors: Susan
authors: S
authors: Flanigan
authors: Haitham
authors: H
authors: Hreybe
authors: Evan
authors: E
authors: Adelstein
authors: Sandeep
authors: S
authors: Jain
authors: Volker
authors: V
authors: Lang
authors: Samir
authors: S
authors: Saba
mesh_terms: D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004556:Electric Injuries / Q000175:diagnosis / Q000453:epidemiology*; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D006333:Heart Failure / Q000453:epidemiology* / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D008297:Male; D010414:Pennsylvania / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D017216:Telemedicine; D016896:Treatment Outcome