title: Failure of the active-fixation mechanism during removal of active-fixation pacing leads.
abstract: BACKGROUND
  Active-fixation pacing leads are being widely employed due to their theoretical advantages when compared with traditional passive-fixation leads: easy fixation and reposition, possible deployment in alternative pacing sites, lower rates of dislodgment, and chronic removability. However, the behavior of the active-fixation mechanism during lead removal has not been yet systematically studied and may have important clinical implications.
  
  
  OBJECTIVE
  To evaluate if the active-fixation mechanism was still working properly in pacing leads that were removed due to different causes.
  
  
  METHODS
  Thirty-one consecutive patients undergoing active-fixation lead removal (40 leads) were studied. Before lead removal, the helix was retracted using the appropriate tool, and fluoroscopy signs were evaluated. After removal, the helix status was examined, and the active-fixation mechanism was once again retested when possible.
  
  
  RESULTS
  In nine of 40 leads (22.5%), the helix remained extended after lead removal in spite of having applied the number of rotations recommended by the manufacturer with the clip-on tool. There was no linear relationship between lead longevity and the presence of an extended helix after lead removal. However, failure of the active-fixation mechanism was more frequent among leads implanted <1 year before versus >1 year before (OR 6.8, 95% CI 1.1-42.7, P = 0.043). In 38% of patients with failure of the active-fixation mechanism, a previous lead reposition had been attempted before lead removal due to significant pacing threshold rise.
  
  
  CONCLUSIONS
  In our series, the active-fixation mechanism failed in up to 22.5% of explanted leads. This may have important clinical implications during active-fixation lead removal and reposition.
authors.affiliation: Electrophysiology Section, Cardiology Department, Hospital Universitari i Politècnic La Fe, Valencia, Spain. cano_osc@gva.es
authors.forename: Oscar
authors.initials: O
authors.lastname: Cano
authors.forename: Joaquín
authors.initials: J
authors.lastname: Osca
authors.forename: María-José
authors.initials: MJ
authors.lastname: Sancho-Tello
authors.forename: José
authors.initials: J
authors.lastname: Olagüe
authors.forename: José E
authors.initials: JE
authors.lastname: Castro
authors.forename: Antonio
authors.initials: A
authors.lastname: Salvador
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020878:Device Removal; D004567:Electrodes, Implanted; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053831:Surgical Fixation Devices