title: Characteristics of the conduction of the left atrium in atrial fibrillation using non-contact mapping.
abstract: BACKGROUND
  We evaluated the conduction properties of the posterior left atrium (LA) using a non-contact mapping (NCM) system as well as the significance of linear ablation at the roof of the posterior LA (LA roof) and inferior region of the posterior LA (LA bottom).
  
  
  RESULTS
  In 133 patients with atrial fibrillation (AF) (83 paroxysmal type, 50 persistent/long-lasting persistent type), we performed complete isolation of the posterior LA including pulmonary veins (Box isolation) using NCM. Isochronal activation maps were analyzed during sinus rhythm (SR), during pacing from the proximal coronary sinus (CS), and during pacing within the posterior LA before and after ablation. In sinus rhythm, horizontal conduction along the LA roof line, but not into the posterior LA wall, was observed in 59% of the patients. During paroxysmal CS pacing, horizontal conduction along the LA bottom line was observed in 69% of the patients. Posterior wall pacing conducted vertically over the LA roof and bottom lines in 98% and 83% of the patients, respectively. During AF, rotor wave conduction into the posterior LA through the LA roof and bottom lines was observed in 85% of the patients. Heterogeneous conduction directions in the posterior LA at the LA roof and bottom lines were observed in 60% of the patients.
  
  
  CONCLUSIONS
  Heterogeneous conduction was observed at the roof and inferior region of the posterior LA in most of these AF patients. The conduction properties of the posterior LA are affected by the direction of the wavefronts, and this may play an important role in the initiation and maintenance of AF. The complete isolation of the posterior LA may prevent AF.
authors.affiliation: Department of Cardiology, Fukuoka University, 7-45-1 Nanakuma, Jounan-ku, Fukuoka 814-0180, Japan. saku-k@cis.fukuoka-u.ac.jp
authors.forename: Hideo
authors.initials: H
authors.lastname: Takashima
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kumagai
authors.forename: Naomichi
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Tomoo
authors.initials: T
authors.lastname: Yasuda
authors.forename: Hideko
authors.initials: H
authors.lastname: Nakashima
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Satoru
authors.initials: S
authors.lastname: Hida
authors.forename: Soichi
authors.initials: S
authors.lastname: Muraoka
authors.forename: Chiharu
authors.initials: C
authors.lastname: Mitsutake
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Miura
authors.forename: Keijiro
authors.initials: K
authors.lastname: Saku
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology*; D018780:Body Surface Potential Mapping / Q000379:methods*; D017115:Catheter Ablation; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged