title: The influence of the external structures in atrial fibrillation patients: Relationship to focal low voltage areas in the left atrium.
abstract: BACKGROUND
  Left atrial (LA) low voltage areas (LVAs) are suggested as an important factor for maintaining atrial fibrillation (AF). The relationship between focal LVAs and anatomical contact is still unclear.
  
  
  METHODS
  Thirty paroxysmal AF (PAF) and 30 persistent AF (PsAF) patients underwent high density voltage mapping during sinus rhythm before any radiofrequency applications were performed. The relationship between the LVA (<0.5mV) and contact area (CoA) demonstrated by enhanced CT and the distance to near external structures were investigated.
  
  
  RESULTS
  The anterior region, posterior wall and left pulmonary vein (LPV) antrum were the three most frequent LVA sites that corresponded to CoA sites, and LVAs mostly overlapped with CoAs (PAF 47/61: 77%, PsAF 63/74: 85%). In the PAF group, patients with posterior-LVAs had a shorter distance to the vertebrae than those without (2.8 ± 1.1 vs. 4.4 ± 1.9 mm; P=0.0086). The distance to the vertebrae was the only predictive factor of the existence of a posterior-LVA and the cut-off value was ≤2.9 mm (P<0.0001). Similarly, an LPV-LVA also had the same results (2.0 ± 0.5 vs. 2.7 ± 0.8mm, P=0.0127) and the cut-off value was ≤2.6mm (P=0.0391). In contrast, the PsAF patients had no difference in the distance when compared to the existence of an LVA.
  
  
  CONCLUSIONS
  Anatomical CoAs demonstrated a spatial relationship to the LVAs in AF patients. In PAF patients, the distance to near external structures in the posterior region was a predictive factor for the existence of an LVA and may have had some influence on maintaining AF, while in PsAF patients no relationship was suggested.
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Hori
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan. Electronic address: nshiro@dokkyomed.ac.jp.
authors.forename: Shiro
authors.initials: S
authors.lastname: Nakahara
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Tsukada
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Nakagawa
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Hayashi
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Komatsu
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Sayuki
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sakai
authors.affiliation: Department of Cardiology, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Taguchi
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology*; D006328:Cardiac Catheterization / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: Atrial fibrillation; Catheter ablation; Electroanatomic mapping; Remodeling; Voltage mapping