title: Substrate of complex fractionated atrial electrograms: evidence by pathologic analysis.
abstract: BACKGROUND
  Ablation of complex fractionated atrial electrograms (CFAE) is an important adjunctive therapy in atrial fibrillation (AF). The present study was to elucidate the substrate underlying CFAE.
  
  
  METHODS
  Nine adult mongrel dogs were involved in the present study. AF was induced through rapid atrial pacing with vagosympathetic nerve stimulation. CFAE was recorded during AF. Ablation was performed at CFAE sites. Based on the location of the ablation scar, the atrial specimens were divided into CFAE and non-CFAE sites. Serial sections of the atrium were stained respectively with hematoxylin-eosin (HE) and the general neural marker protein gene product 9.5 (PGP9.5). We compared the characteristics of the myocardium and the ganglionated plexus (GPs) distribution between the CFAE and non-CFAE sites.
  
  
  RESULTS
  The myocardium of non-CFAE sites was well-organized with little intercellular substance. However, the myocardium in the CFAE site was disorganized with more interstitial tissue ((61.7 ± 24.3)% vs. (34.1 ± 9.2)%, P < 0.01). GPs in the CFAE site were more abundant than in non-CFAE sites ((34.45 ± 37.46) bundles/cm(2) vs. (6.73 ± 8.22) bundles/cm(2), P < 0.01).
  
  
  CONCLUSIONS
  The heterogeneity of the myocardium and GPs distribution may account for the substrate of CFAE and serve as a potential target of ablation.
authors.affiliation: Department of Cardiology, 406th Hospital of Chinese People's Liberation Army, Dalian, Liaoning, China.
authors.forename: De-jun
authors.initials: DJ
authors.lastname: You
authors.forename: Dong
authors.initials: D
authors.lastname: Chang
authors.forename: Shu-long
authors.initials: SL
authors.lastname: Zhang
authors.forename: Dong-hui
authors.initials: DH
authors.lastname: Yang
authors.forename: Lian-jun
authors.initials: LJ
authors.lastname: Gao
authors.forename: Xiao-meng
authors.initials: XM
authors.lastname: Yin
authors.forename: Zhen-liang
authors.initials: ZL
authors.lastname: Chu
authors.forename: Yun-long
authors.initials: YL
authors.lastname: Xia
authors.forename: Yu-chun
authors.initials: YC
authors.lastname: Wang
authors.forename: Ying-xue
authors.initials: YX
authors.lastname: Dong
authors.forename: Yan-zong
authors.initials: YZ
authors.lastname: Yang
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000473:pathology; D004285:Dogs; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D009206:Myocardium / Q000473:pathology*