title: Autonomic neural remodeling of the pulmonary vein-left atrium junction in a prolonged right atrial pacing canine model.
abstract: BACKGROUND
  No evidence has been presented to show whether autonomic neural remodeling occurs in pulmonary vein-left atrium (PV-LA) junction and what an important role it may play in AF. This study aims to find out these issues in a prolonged rapid atrial pacing canine model.
  
  
  METHODS
  Twelve healthy mongrel dogs were randomly divided into two groups, six in each: the paced group underwent rapid right atrial pacing at 400 beats per minute for 4 weeks, and the control group was not paced. The effective refractory period (ERP) of left superior pulmonary vein-left atrium (LSPV-LA) junction in all animals was determined immediately after 4 weeks. Tissues were removed from 1 cm around all PV-LA junctions. Immunohistochemical staining and western blotting were performed to examine the expression of tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT).
  
  
  RESULTS
  Compared with the control group, ERP of LSPV-LA junction of the paced group was significantly shortened ([83.33 ± 16.33] ms vs [111.67 ± 20.41] ms, P < 0.05). Spontaneous atrial fibrillation developed in two animals in the paced group, but in none of the control group. Immunohistochemistry showed that the average density and heterogeneity of both TH- and ChAT-positive nerves at LSPV-LA junction in the paced group were significantly higher compared to the control group (P < 0.01). Western blotting showed that the expression of TH and ChAT at four PV-LA junctions in the paced group also increased markedly compared with the control group (P < 0.01).
  
  
  CONCLUSIONS
  Autonomic neural remodeling did exist in PV-LA junction after prolonged atrial pacing, which may contribute to the initiation of atrial fibrillation and be significant in its treatment by radiofrequency catheter ablation.
authors.affiliation: Shandong Provincial Qianfoshan Hospital, and the Department of Clinical Medicine, School of Medicine, Shandong University, Jinan City, China.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Zheng
authors.forename: Yujiao
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhongsu
authors.initials: Z
authors.lastname: Wang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Li
authors.forename: Xujuan
authors.initials: X
authors.lastname: Hou
authors.forename: Wenchang
authors.initials: W
authors.lastname: Duan
authors.forename: Yinglong
authors.initials: Y
authors.lastname: Hou
mesh_terms: D000818:Animals; D016275:Atrial Function / Q000502:physiology*; D001341:Autonomic Nervous System; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004285:Dogs; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male; D009473:Neuronal Plasticity; D011667:Pulmonary Veins
keywords: atrial fibrillation; autonomic neural remodeling; pulmonary vein-left atrium junction