title: Contribution of ethylenetetrafluoroethylene (ETFE) insulation to the electrical performance of Riata® silicone leads having externalized conductors.
abstract: BACKGROUND
  The insulation of St. Jude Medical Riata® leads contains a polytetrafluoroethylene (PTFE) liner, silicone tubing, and ethylenetetrafluoroethylene (ETFE) coating on individual cable conductors. ETFE has sufficient dielectric strength to assure electrical function. This investigation intended to analyze performance of leads with and without externalized conductors and with intact and breached ETFE.
  
  
  METHODS
  Testing was performed on ETFE-coated conductors to determine their ability to deliver high-voltage therapy. Tests were performed on samples under different conditions and current leakage was measured. A high-voltage test and a cyclic pulse test were performed, and the effect of lead modifications on the potential gradient from a high-voltage shock was used to determine functionality. Measurements from modified Riata® leads were compared with a control lead with all insulation and conducting elements intact.
  
  
  RESULTS
  Current leakage for all conditions tested, was within the acceptance criteria for the high-voltage test and the cyclic pulse test. In conductors that underwent cyclic testing, the highest value of current leakage was within the limit of acceptability for both phases of the test. Testing of leads with externalized conductors and breached ETFE showed similar potential gradients compared with a control lead.
  
  
  CONCLUSIONS
  Testing of ETFE-coated conductors following multiple preconditioning steps showed that ETFE serves as a redundant layer of insulation. In the event that the ETFE coating is breached, the potential gradient seen resulting from a high-voltage defibrillation shock was similar to a lead with no breach to the ETFE, even after 100 shocks.
authors.affiliation: Implantable Electronic Systems Division, St. Jude Medical, 15900 Valley View Court, Sylmar, CA 91342, USA. afischer@sjm.com
authors.forename: Avi
authors.initials: A
authors.lastname: Fischer
authors.forename: Russell
authors.initials: R
authors.lastname: Klehn
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017147:Defibrillators, Implantable; D004553:Electric Conductivity; D004567:Electrodes, Implanted; D004867:Equipment Design; D004868:Equipment Failure; D019544:Equipment Failure Analysis; D005466:Fluorocarbons / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D011138:Polytetrafluoroethylene / Q000031:analogs & derivatives
chemical_list: D020099:Coated Materials, Biocompatible; D005466:Fluorocarbons; D012828:Silicones; C040378:poly(ethylene-tetrafluoroethylene); D011138:Polytetrafluoroethylene