title: Accelerating risk of Fidelis lead fracture.
abstract: BACKGROUND
  Sprint Fidelis (Medtronic Inc., Minneapolis, Minnesota) is a 6.6-F implantable cardioverter-defibrillator lead. In October 2007 the manufacturer suspended distribution of Sprint Fidelis leads secondary to high early fracture rates. Reprogramming of lead impedance alerts was recommended to try to reduce inappropriate shocks.
  
  
  OBJECTIVE
  This study sought to assess how the hazard of Fidelis fracture varies with time, whether lead impedance alert thresholds programmed after recall have prevented inappropriate shocks, and predictors of lead fracture.
  
  
  METHODS
  We collected clinical and device interrogation data on all lead fractures and performed a Kaplan-Meier analysis. We performed a case control study to examine univariate and multivariate predictors of lead fracture.
  
  
  RESULTS
  There have been 17 lead fractures in our cohort of 480 Sprint Fidelis (model 6949) leads, median follow-up 19.8 months. The hazard of fracture increased significantly with time by a power of 2.74 (95% confidence interval: 2.57 to 2.91, P <.0001). Reprogrammed lead impedance thresholds prevented inappropriate shocks in only 1 of 6 patients. Independent predictors of lead fracture were greater left ventricular ejection fraction (P = .0011) and noncephalic venous access (P = .0224).
  
  
  CONCLUSIONS
  The risk of lead fracture increased with time by a power of 2.74. Reprogrammed lead impedance thresholds prevented inappropriate shocks in only 1 of 6 patients. Independent predictors of lead fracture were greater left ventricular ejection fraction and noncephalic access.
authors.affiliation: University of Ottawa Heart Institute, Ottawa, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Farwell
authors.forename: Martin S
authors.initials: MS
authors.lastname: Green
authors.forename: Robert
authors.initials: R
authors.lastname: Lemery
authors.forename: Michael H
authors.initials: MH
authors.lastname: Gollob
authors.forename: David H
authors.initials: DH
authors.lastname: Birnie
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D017097:Electric Impedance; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D004869:Equipment Safety; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors