title: Pacing and sensing interference by air bubble surrounding the non-extended helix of intact active fixation lead.
abstract: BACKGROUND
  Active fixation pacing leads with silicon cylinder tips have been used for their safety and flexibility. Measurement of baseline sensing/pacing characteristics before fixation of helix helps to identify the optimal pacing site, but we encountered difficulties in making these measurements despite multiple attempts with the model LPA 1200M lead. To identify the cause and overcome this complication, we compared 4 different retractable active fixation lead models, which enabled baseline sensing/pacing measurements before extension of helix. METHODS AND RESULTS: We immersed 4 different lead tips and rings in a 0.18% saline solution, and measured the lead impedance before and after flushing of air bubble visible inside the lead tip. Before evacuation of the air bubble, the impedance of the model LPA 1200M lead was >4,000 Ω in 8 out of 10 measurements, although that of the other leads was within the measurable range. After evacuation of the air bubble, the lead impedance returned to within the measurable range. There was no prominent change in the impedance of the metal cylinder tip lead.
  
  
  CONCLUSIONS
  Air bubbles may interfere with the measurement of baseline sensing/pacing characteristics before active fixation of pacing leads with cylindrical silicon tips. In the case of high impedance beyond the measurable range before extension of helix, the measurement should be repeated after fixation into the myocardium before suspecting lead dysfunction.
authors.affiliation: Second Department of Internal Medicine, University of Occupational and Environmental Health, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Oginosawa
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Abe
authors.forename: Hisaharu
authors.initials: H
authors.lastname: Ohe
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Hayashi
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Kohno
authors.forename: Taichi
authors.initials: T
authors.lastname: Watabe
authors.forename: Masao
authors.initials: M
authors.lastname: Takahashi
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Fujino
authors.forename: Masahito
authors.initials: M
authors.lastname: Tamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Otsuji
mesh_terms: D000388:Air; D016477:Artifacts; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004567:Electrodes, Implanted; D004867:Equipment Design; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012804:Sick Sinus Syndrome / Q000503:physiopathology / Q000628:therapy*