title: Very late follow-up of a passive defibrillator lead under recall: do failure rates increase during long-term observation.
abstract: BACKGROUND
  The Medtronic Sprint Fidelis lead (SFL; Medtronic Inc., Minneapolis, MN, USA) has a significantly impaired long-term survival, and active fixation leads fare worse than passive leads. The goal of this study was to present data of a series of passive SFL only with very long mean follow-up of more than 6 years.
  
  
  METHODS
  Patients in whom a passive SFL was implanted in two large Swiss centers were followed. We excluded eight (5.5%) patients with a follow-up of <6 months. Patients who died or were lost during follow-up were censored at death or last device check, all others on January 31, 2014. We employed two different definitions of failure: strict = fracture with inappropriate discharge; sudden increase in impedance >1,500 or high-voltage impedance >100 Ohm; >300 nonphysiological short interventricular-intervals. Lenient = any of the above plus a linear increase in impedance >1,500 Ohm or a linear decrease in sensing to a level that treating cardiologists considered inappropriate.
  
  
  RESULTS
  We included 137 patients. Age was 60 ± 12 years. Mean and median follow-up were 6.2 ± 2.1 and 6.8 (interquartile range 4.8-7.8) years. Applying the strict definition, 12 leads (8.8%) were replaced after 4.9 ± 2.4 years (range 1.2-8.1). Applying the lenient definition, 14 leads (10.2%) failed. Cumulative lead survival was 98.5% at 3, 96.9% at 4, 94.2% at 5, and 93.1% at 6 years. Leads "at risk" were: n = 122 (89%), 115 (84%), 101 (74%), and 88 (64%).
  
  
  CONCLUSIONS
  In this population with passive SFLs, 5-year lead survival is impaired with 94.2% based on 74% of leads "at risk" at this time point.
authors.affiliation: University Hospital of Basel, Basel, Switzerland.
authors.forename: Simon Martin
authors.initials: SM
authors.lastname: Frey
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.forename: Regula
authors.initials: R
authors.lastname: Kraus
authors.forename: Peter
authors.initials: P
authors.lastname: Ammann
authors.forename: Michael
authors.initials: M
authors.lastname: Kühne
authors.forename: Stefan
authors.initials: S
authors.lastname: Osswald
authors.forename: Beat
authors.initials: B
authors.lastname: Schaer
mesh_terms: D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004567:Electrodes, Implanted / Q000009:adverse effects*; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D057051:Product Recalls and Withdrawals; D012189:Retrospective Studies; D013557:Switzerland; D016896:Treatment Outcome
keywords: Medtronic™ Sprint Fidelis® lead; active lead configuration; implantable cardioverter defibrillator (ICD); long-term performance; passive lead configuration