title: Mechanisms of the maintenance of atrial fibrillation: role of the complex fractionated atrial electrogram assessed by noncontact mapping.
abstract: BACKGROUND
  The role of complex fractionated atrial electrograms (CFAEs) in the maintenance of atrial fibrillation (AF) has not been well clarified.
  
  
  OBJECTIVE
  The purpose of this study was to examine the mechanisms of AF maintenance, especially in relation to CFAE.
  
  
  METHODS
  Endocardial mapping of the left atrium was performed during AF using a three-dimensional noncontact mapping system in 16 patients with paroxysmal AF.
  
  
  RESULTS
  During AF, focal discharges were found at the pulmonary vein and sites within the CFAE region (3.0 +/- 1.9 vs. 2.8 +/- 1.5 times/s; P = NS) but not in the non-CFAE region. One to four meandering waves propagated over various pathways during AF. The frequency of the wave break and pivoting activation in the CFAE region were significantly higher than in the non-CFAE region (5.6 +/- 3.6 vs. 0 +/- 0 times/s, P <.0001 and 5.0 +/- 2.1 vs. 0.3 +/- 0.8 times/s; P <.0001). Wave fusion in the CFAE region was more frequently observed than in the non-CFAE region (6.5 +/- 5.8 vs. 3.6 +/- 3.1 times/s; P <.05). Conduction velocity in the CFAE region was slower than in the non-CFAE region (0.7 +/- 0.4 vs. 1.9 +/- 0.5 m/s; P <.0001). The generation of a new wave was associated with the wave break, fusion, and focal discharge. Furthermore, perpetuation of these waves accompanied by slow conduction and pivoting activation was mostly observed in the CFAE region.
  
  
  CONCLUSIONS
  The CFAE region plays an important role in the perpetuation of AF. In addition to focal discharge, wave break and fusion associated with slow conduction and pivoting activation in the CFAE region sustained wave propagation, resulting in the maintenance of AF.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. yamabe_hi@ybb.ne.jp
authors.forename: Hiroshige
authors.initials: H
authors.lastname: Yamabe
authors.forename: Kenji
authors.initials: K
authors.lastname: Morihisa
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Uemura
authors.forename: Koji
authors.initials: K
authors.lastname: Enomoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawano
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D003971:Diastole; D022062:Electrophysiologic Techniques, Cardiac; D004699:Endocardium; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins; D013223:Statistics as Topic; D013318:Stroke Volume