title: Experimental evaluation of myocardial fibrosis in a rapid atrial pacing model in New Zealand rabbits using quantitative analysis of ultrasonic backscatter.
abstract: BACKGROUND
  The aim of this study was the establishment of a rapid atrial pacing (RAP)-induced atrial fibrillation (AF) model with electrophotoluminescence and the application of ultrasonic backscatter quantitative analysis of the degree of myocardial fibrosis in New Zealand white rabbits.
  
  
  METHODS
  Sixteen New Zealand white rabbits were randomly divided into 2 groups: 1) a sham operation group (n=8) with implanted electrodes and no rapid pacing and 2) a pacing group (n=8) with an AF model induced by short-term rapid right atrial pacing for 12 h. Establishment of an AF model, atrial myocardium of myocardial fibrosis was tested by Masson staining and expression of collagen I and collagen III protein was detected with pathologic immunohistochemistry integrated back-scatter (IBS). Back scattering integral cycle variation (CVIB) were detected in atrial septal and posterior wall of the right atrium.
  
  
  RESULTS
  Rapid atrial pacing successfully induced the atrial fibrillation model in rabbits. Masson staining showed myocardial fibrosis significantly increased in the pacing group. Expression of collagen I and collagen III protein was strongly positive in the pacing group, and expression of collagen I and collagen III protein were weakly positive in the sham operation group. Compared with the sham operation group, AII was increased (8.24±0.85 vs. 15.56±1.30, P<0.05) and (7.58±0.56 vs. 16.60±2.45, P<0.05). CVIB was significantly decreased (2.78±0.86 vs. 1.08±0.13, P<0.05) and (3.12±0.65 vs. 1.56±0.15, P<0.05) in septal and posterior wall of the right atrium of the pacing group.
  
  
  CONCLUSIONS
  Ultrasonic backscatter measurement technique can be used to evaluate degree of myocardial fibrosis in a right atrial pacing-induced atrial arrhythmia model.
authors.affiliation: Clinical Postdoctoral Research Station, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Juan
authors.initials: J
authors.lastname: Sun
authors.affiliation: Function Center, Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Zhang
authors.initials: Z
authors.lastname: Rong
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Najina
authors.initials: N
authors.lastname: Wugeti
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Adila
authors.initials: A
authors.lastname: Azhati
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Yujun
authors.initials: Y
authors.lastname: GUo
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Haili
authors.initials: H
authors.lastname: Liu
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Ruping
authors.initials: R
authors.lastname: Qian
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Long
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Heart Center, The First Affiliated Hospital of Xinjiang Medical University, Urumuqi, China (mainland).
authors.forename: Yitong
authors.initials: Y
authors.lastname: Ma
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy; D009202:Cardiomyopathies / Q000503:physiopathology*; D005355:Fibrosis; D023421:Models, Animal; D010138:Pacemaker, Artificial; D011817:Rabbits; D014465:Ultrasonics