title: Preventing overdiagnosis of implantable cardioverter-defibrillator lead fractures using device diagnostics.
abstract: OBJECTIVE
  This study sought to use implantable cardioverter-defibrillator (ICD) diagnostics to discriminate ICD lead fractures from normally functioning leads with high impedance and from connection problems between the lead and header.
  
  
  BACKGROUND
  ICD diagnostics facilitate identification of fractures, but there are no accepted criteria for discriminating fractures from other causes of high impedance and/or nonphysiological "noise" oversensing.
  
  
  METHODS
  We analyzed a development set of 91 leads to construct a stepwise algorithm based on ICD diagnostics. It included 40 fractures, 30 connection problems, and 21 functioning leads that triggered high-impedance alerts. Then we applied this algorithm to an independent test set of 100 leads: 70 fractures and 30 intact leads with connection problems that were misdiagnosed clinically as fractures. In the algorithm, either extremely high maximum impedance or noise oversensing with a normal impedance trend indicated a fracture. A short interval from surgery to impedance rise or prolonged stable impedance after an abrupt rise indicated a connection problem. A gradual impedance increase or stable, high impedance indicated a functioning lead.
  
  
  RESULTS
  In the test set, the algorithm correctly classified 100% of fractures (95% confidence interval [CI]: 95% to 100%) and 87% of connection problems that were misdiagnosed as fractures (95% CI: 70% to 95%).
  
  
  CONCLUSIONS
  An algorithm using only ICD diagnostics identifies leads with oversensing or high impedance as fractures or connection problems with a high degree of accuracy.
authors.affiliation: The Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA. swerdlow@ucla.edu
authors.forename: Charles D
authors.initials: CD
authors.lastname: Swerdlow
authors.forename: Haresh
authors.initials: H
authors.lastname: Sachanandani
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Gunderson
authors.forename: Kevin T
authors.initials: KT
authors.lastname: Ousdigian
authors.forename: Mark
authors.initials: M
authors.lastname: Hjelle
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Ellenbogen
mesh_terms: D000465:Algorithms; D017147:Defibrillators, Implantable; D004868:Equipment Failure; D006801:Humans