title: Left atrial pathological degeneration assessed by integrated backscatter transesophageal echocardiography as a predictor of progression to persistent atrial fibrillation: results from a prospective study of three-years follow-up.
abstract: BACKGROUND
  It is recognized that one of the causes of atrial fibrillation (AF) is pathological degeneration of the left atrium (LA). However, prospective study that elucidated the relationship between the incidence of persistent AF and pathological degeneration has not been performed. The purpose of this study was to elucidate the usefulness of integrated backscatter (IBS) values for the prediction of progression from paroxysmal AF (PAF) to persistent AF.
  
  
  METHODS
  We measured IBS values of the entire LA wall at 5 mm intervals (except the posterior wall) in 27 patients with paroxysmal AF and evaluated progression to persistent AF for three years. IBS values were acquired with transesophageal echocardiography (TEE) using a 4-7 MHz transducer. IBS values were calculated as the average power of the backscattered signal from regions of interest (ROI). Each IBS value was color-coded to construct three dimensional maps.
  
  
  RESULTS
  Average IBS values of total voxels in color-coded maps in the persistent AF group were significantly greater than those in the non-persistent AF group (25.8 ± 5.0 dB vs. 17.4 ± 10.2 dB, p = 0.047), whereas there was no significant difference in LA diameter between the persistent AF and the non-persistent AF group. There was significant difference in persistent AF-free survival after the baseline measurements in the subjects stratified by IBS value (< 20 dB versus ≥ 20 dB) (univariate Cox regression analysis: hazard ratio: 8.74, p =0.046).
  
  
  CONCLUSIONS
  Using IBS values measured by TEE, we can identify an increase in atrial degeneration that may predict the occurrence of persistent AF before LA dilation.
authors: Department of Cardiology, Gifu University Graduate School of Medicine, Gifu, Japan.
authors: Tomoki
authors: T
authors: Kubota
authors: Masanori
authors: M
authors: Kawasaki
authors: Nobuhiro
authors: N
authors: Takasugi
authors: Hajime
authors: H
authors: Imai
authors: Yoshiyuki
authors: Y
authors: Ishihara
authors: Munenori
authors: M
authors: Okubo
authors: Shigekiyo
authors: S
authors: Takahashi
authors: Hironobu
authors: H
authors: Sato
authors: Kazuhiko
authors: K
authors: Nishigaki
authors: Genzou
authors: G
authors: Takemura
authors: Shinya
authors: S
authors: Minatoguchi
mesh_terms: D001281:Atrial Fibrillation / Q000000981:diagnostic imaging*; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity