title: Microelectrode array measurement of potassium ion channel remodeling on the field action potential duration in rapid atrial pacing rabbits model.
abstract: BACKGROUND
  Atrial fibrillation (AF) arises from abnormalities in atrial structure and electrical activity. Microelectrode arrays (MEA) is a real-time, nondestructive measurement of the resting and action potential signal, from myocardial cells, to the peripheral circuit of electrophysiological activity. This study examined the field action potential duration (fAPD) of the right atrial appendage (RAA) by MEA in rapid atrial pacing (RAP) in the right atrium of rabbits. In addition, this study also investigated the effect of potassium ion channel blockers on fAPD.
  
  
  METHODS
  40 New Zealand white rabbits of either sex were randomly divided into 3 groups: 1) the control, 2) potassium ion channel blocker (TEA, 4-Ap and BaCl2), and 3) amiodarone groups. The hearts were quickly removed and right atrial appendage sectioned (slice thickness 500 μm). Each slice was perfused with Tyrode's solution and continuously stimulated for 30 minutes. Sections from the control group were superfused with Tyrode's solution for 10 minutes, while the blocker groups and amiodarone were both treated with their respective compounds for 10 minutes each. The fAPD of RAA and action field action potential morphology were measured using MEA.
  
  
  RESULTS
  In non-pace (control) groups, fAPD was 188.33 ± 18.29 ms after Tyrode's solution superfusion, and 173.91 ± 6.83 ms after RAP. In pace/potassium ion channel groups, TEA and BaCl2 superfusion prolonged atrial field action potential (fAPD) (control vs blocker: 176.67 ± 8.66 ms vs 196.11 ± 10.76 ms, 182.22 ± 12.87 ms vs 191.11 ± 13.09 ms with TEA and BaCl2 superfusion, respectively, P < 0.05). 4-AP superfusion significantly prolonged FAPD. In pace/amiodarone groups, 4-Ap superfusion extended fAPD.
  
  
  CONCLUSIONS
  MEA was a sensitive and stable reporter for the measurement of the tissue action potential in animal heart slices. After superfusing potassium ion channel blockers, fAPD was prolonged. These results suggest that Ito, IKur and IK1 remodel and mediate RAP-induced atrial electrical remodeling. Amiodarone alter potassium ion channel activity (Ito, IKur, IK1 and IKs), shortening fAPD.
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University Urumqi, Xinjiang.
authors.forename: Juan
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Electrocardiogram, Huadong Hospital Jing'an District, Shanghai.
authors.forename: Huang
authors.initials: H
authors.lastname: Yan
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University Urumqi, Xinjiang.
authors.forename: Najina
authors.initials: N
authors.lastname: Wugeti
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University Urumqi, Xinjiang.
authors.forename: Yujun
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University Urumqi, Xinjiang.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University Urumqi, Xinjiang.
authors.forename: Mei
authors.initials: M
authors.lastname: Ma
authors.affiliation: Department of Electrocardiogram, Huadong Hospital Jing'an District, Shanghai.
authors.forename: Xingui
authors.initials: X
authors.lastname: Guo
authors.affiliation: Department of Electrocardiogram, Huadong Hospital Jing'an District, Shanghai.
authors.forename: Changan
authors.initials: C
authors.lastname: Jiao
authors.affiliation: Department of Electrocardiogram, Huadong Hospital Jing'an District, Shanghai.
authors.forename: Wenli
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Electrocardiogram, Huadong Hospital Jing'an District, Shanghai.
authors.forename: Tianqi
authors.initials: T
authors.lastname: Li
keywords: Atrial fibrillation; field action potential duration; microelectrode arrays; potassium ion channel blocker; rapid atrial pacing