title: Mechanical and substrate abnormalities of the left atrium assessed by 3-dimensional speckle-tracking echocardiography and electroanatomic mapping system in patients with paroxysmal atrial fibrillation.
abstract: BACKGROUND
  Left atrial (LA) remodeling progresses to electrical remodeling, contractile remodeling, and subsequently structural remodeling. Little is known about the relationship between LA electrical and anatomical remodeling and LA mechanical function.
  
  
  OBJECTIVE
  We aimed to clarify the relationship between LA mechanical function using 3-dimensional speckle-tracking echocardiography (3D-STE) and LA electrical remodeling using an electroanatomic mapping system (CARTO 3) and to estimate atrial fibrillation (AF) substrate in patients with paroxysmal AF (PAF).
  
  
  METHODS
  A total of 52 patients with PAF (41 (79%) men; mean age 61 ± 11 years) undergoing their initial pulmonary vein isolation (PVI) were examined. The standard deviation of the time to peak strain in each LA segment (%SD-TPS) was analyzed as an index of LA dyssynchrony using 3D-STE before PVI. Contact LA bipolar voltage and activation maps were constructed during sinus rhythm before PVI using CARTO 3. The LA total activation time was measured and low-voltage zones (LVZs) were determined with a local bipolar electrogram amplitude of <0.5 mV. The patients were divided into those with an LVZ (LVZ group; n = 23) and those without an LVZ (non-LVZ group; n = 29).
  
  
  RESULTS
  The %SD-TPS was significantly higher (14.1 ± 5.7 vs 8.0 ± 5.1; P=.0002) in the LVZ group than in the non-LVZ group and was an independent determinant of the LVZ (odds ratio 1.21; 95% confidence interval 1.04-1.49; P=.01). In addition, the LA total activation time was weakly correlated with the %SD-TPS.
  
  
  CONCLUSIONS
  LA dyssynchrony and conduction delay exist in patients with PAF. The 3D-STE enabled noninvasive estimation of LA electrical remodeling and AF substrate.
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan. Electronic address: nakanoy@hiroshima-u.ac.jp.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Nakano
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Hidaka
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Oda
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Kajihara
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Tokuyama
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Uchimura
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Sairaku
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Chikaaki
authors.initials: C
authors.lastname: Motoda
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Mai
authors.initials: M
authors.lastname: Fujiwara
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawazoe
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Matsumura
authors.affiliation: Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Kihara
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D016279:Atrial Function, Left; D017115:Catheter Ablation / Q000379:methods; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000601:surgery
keywords: Atrial fibrillation; Conduction delay; Dyssynchrony; Electroanatomic mapping; Left atrium; Remodeling; Speckle-tracking echocardiography