title: Effectiveness of epicardial atrial pacing using a bipolar steroid-eluting endocardial lead with active fixation in an experimental model.
abstract: OBJECTIVE
  To assess the effectiveness of bipolar epicardial atrial pacing using an active fixation bipolar endocardial lead implanted on the atrial surface in an experimental model.
  
  
  METHODS
  A total of ten Large White adult pigs underwent pacemaker implantation under general anesthesia. Atrial pacing and sensing parameters were obtained at the procedure, immediate postoperative period and on the 7th and the 30th postoperative in unipolar and bipolar configurations.
  
  
  RESULTS
  All procedures were successfully performed. There were no perioperative complications and no early deaths. Atrial pacing and sensing parameters for both unipolar and bipolar modes remained stable throughout the study. We observed a progressive increase in atrial thresholds, ranging from 0.49 ± 0.35 (at implantation) to 1.86 ± 1.31 volts (30th postoperative day), in unipolar mode. Atrial impedance measurements decreased slightly over time, ranging from 486.80 ± 126.35 Ohms (at implantation) to 385.0 ± 80.52 Ohms (30th postoperative day). Atrial sensing measures remained stable from the immediate postoperative period until the end of the study.
  
  
  CONCLUSIONS
  The bipolar active fixation endocardial lead implanted epicardially can provide stable conditions of pacing and sensing parameters throughout the postoperative follow-up.
authors.affiliation: Postgraduate Program in Thoracic and Cardiovascular Surgery, Division of Cardiothoracic Surgery, Heart Institute (InCor), Clinics Hospital, Medical School, University of Sao Paulo (USP), Brazil.
authors.forename: Sávia Christina Pereira
authors.initials: SC
authors.lastname: Bueno
authors.forename: Wagner Tetsuji
authors.initials: WT
authors.lastname: Tamaki
authors.forename: Marcelo Fiorelli Alexandrino da
authors.initials: MF
authors.lastname: Silva
authors.forename: Cristiane Maciel
authors.initials: CM
authors.lastname: Zambolim
authors.forename: Kátia Regina da
authors.initials: KR
authors.lastname: Silva
authors.forename: Martino
authors.initials: M
authors.lastname: Martinelli Filho
authors.forename: Roberto
authors.initials: R
authors.lastname: Costa
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004567:Electrodes, Implanted; D004867:Equipment Design / Q000379:methods*; D006325:Heart Atria / Q000503:physiopathology / Q000601:surgery*; D061646:Operative Time; D010138:Pacemaker, Artificial; D011184:Postoperative Period; D015203:Reproducibility of Results; D013256:Steroids / Q000008:administration & dosage*; D013499:Surface Properties; D013552:Swine; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D013256:Steroids