title: Right-sided implantation and subpectoral position are predisposing factors for fracture of a 6.6 French ICD lead.
abstract: BACKGROUND
  The Medtronic Sprint Fidelis (Medtronic Inc., Minneapolis, MN, USA) lead family is associated with an unacceptable incidence of premature lead failure. There are limited data on risk factors for lead fracture. We hypothesized that factors leading to potential increased forces on the lead related to device implantation or technique may be associated with premature lead failure.
  
  
  METHODS
  We reviewed the implant data from our group and identified 176 patients who received active fixation Medtronic Fidelis (Model 6931, single coil and Model 6949, dual coil) leads. Implant data, including age, sex, venous access site, implant side, implant location, and number of venous leads were reviewed. Hospital, pacemaker clinic, and Medtronic registration databases were reviewed for evidence of lead failure, replacement, or abandonment. Data was evaluated in univariate and multivariate regression analyses.
  
  
  RESULTS
  Of the 176 leads implanted, 10 (5.7%) were noted to develop malfunction. This presented as inappropriate shocks from sensed noise or elevated impedance measurements. Of the above noted implant features, only right-sided (vs left-sided) implant (hazard ratio [HR] 18.8, 95% confidence intervals [CI] 3.8, 93.3), and subpectoral implant (vs prepectoral; HR 14.31, 95% CI 3.2, 64.0) were predictive of lead failure in maximally adjusted models.
  
  
  CONCLUSIONS
  We have identified both right-sided implantation and subpectoral generator positioning as factors associated with premature lead malfunction in Fidelis active fixation leads. Clinical decisions regarding patient management should incorporate these findings in regard to lead replacement in high-risk patients.
authors.affiliation: New York University School of Medicine, New York, New York, USA. Neil.Bernstein@nyumc.org
authors.forename: Neil E
authors.initials: NE
authors.lastname: Bernstein
authors.forename: Edmund T
authors.initials: ET
authors.lastname: Karam
authors.forename: Anthony
authors.initials: A
authors.lastname: Aizer
authors.forename: Brian C
authors.initials: BC
authors.lastname: Wong
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Holmes
authors.forename: Scott A
authors.initials: SA
authors.lastname: Bernstein
authors.forename: Larry A
authors.initials: LA
authors.lastname: Chinitz
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable / Q000706:statistics & numerical data*; D004567:Electrodes, Implanted / Q000706:statistics & numerical data*; D004868:Equipment Failure / Q000706:statistics & numerical data*; D005260:Female; D006352:Heart Ventricles / Q000601:surgery*; D006801:Humans; D008297:Male; D012307:Risk Factors; D014481:United States / Q000453:epidemiology