title: Effect of Steroid Elution on Electrical Performance and Tissue Responses in Quadripolar Left Ventricular Cardiac Vein Leads.
abstract: BACKGROUND
  The use of steroid elution (SE) electrode in a cardiac pacing lead is known to suppress myocardial inflammation to lower pacing thresholds (PTs). SE has been widely utilized on the distal electrode of left ventricular cardiac vein (LVCV) leads used in cardiac resynchronization therapy (CRT). However, no paired comparison in effect of SE has been studied in proximal electrodes of quadripolar LVCV leads.
  
  
  METHODS
  We evaluated electrical performance and tissue responses of quadripolar LVCV lead electrodes with and without SE in two canine studies with a total of 14 canines. Extended bipolar PT and pacing impedance of the LVCV electrodes to right ventricle coil were collected via an implantable CRT device/programmer or a percutaneous threshold analyzer/pacing analyzer at weeks 0, 1, 2, 4, 6, 8, and 12. Gross and histopathological examinations of the canines were performed at the end of the studies.
  
  
  RESULTS
  Our preclinical studies showed that SE had significant effects on the long-term pacing performance of quadripolar LVCV leads. The SE tip and ring electrodes reduced postimplant PT peak and chronic PT, P = 0.038. Histological examination of the perilead tissue capsules at 12 weeks showed a reduced thickness for the location of SE electrodes.
  
  
  CONCLUSIONS
  SE electrodes in quadripolar LVCV leads lower the PTs, and therefore may potentially reduce long-term current drain of CRT systems, thus improving the device longevity. These preclinical data serve as rationale to include SE on proximal electrodes for the Attain Performa LVCV leads and future quadripolar LVCV leads development.
authors.affiliation: Cardiac Rhythm Heart Failure Research & Technology, Medtronic PLC, Mounds View, Minnesota.
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Physiological Research Laboratories, Medtronic PLC, Minneapolis, Minnesota.
authors.forename: Nicole
authors.initials: N
authors.lastname: Kirchhof
authors.affiliation: Cardiac Rhythm Heart Failure Research & Technology, Medtronic PLC, Mounds View, Minnesota.
authors.forename: Shelby
authors.initials: S
authors.lastname: Li
authors.affiliation: Cardiac Rhythm Heart Failure Research & Technology, Medtronic PLC, Mounds View, Minnesota.
authors.forename: Douglas
authors.initials: D
authors.lastname: Hine
authors.affiliation: Cardiac Rhythm Heart Failure Research & Technology, Medtronic PLC, Mounds View, Minnesota.
authors.forename: Rick
authors.initials: R
authors.lastname: McVenes
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000008:administration & dosage* / Q000494:pharmacology; D004285:Dogs; D004567:Electrodes, Implanted; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000494:pharmacology; D006352:Heart Ventricles / Q000187:drug effects* / Q000473:pathology; D008297:Male; D014680:Veins; D016276:Ventricular Function / Q000187:drug effects*
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone
keywords: pacing threshold; quadripolar left ventricular cardiac vein lead; steroid elution