title: Motion of left atrial appendage as a determinant of thrombus formation in patients with a low CHADS2 score receiving warfarin for persistent nonvalvular atrial fibrillation.
abstract: BACKGROUND
  The aim of this study was to define the independent determinants of left atrial appendage (LAA) thrombus among various echocardiographic parameters measured by Velocity Vector Imaging (VVI) in patients with nonvalvular atrial fibrillation (AF) receiving warfarin, particularly in patients with a low CHADS2 score.
  
  
  METHODS
  LAA emptying fraction (EF) and LAA peak longitudinal strain were measured by VVI using transesophageal echocardiography in 260 consecutive patients with nonvalvular persistent AF receiving warfarin. The patients were divided into two groups according to the presence (n=43) or absence (n=217) of LAA thrombus. Moreover, the patients within each group were further divided into subgroups according to a CHADS2 score ≤1.
  
  
  RESULTS
  Multivariate logistic regression analysis showed that LAAEF was an independent determinant of LAA thrombus in the subgroup of 140 with a low CHADS2 score. Receiver operating characteristics curve analysis showed that an LAAEF of 21% was the optimal cutoff value for predicting LAA thrombus.
  
  
  CONCLUSIONS
  LAA thrombus formation depended on LAA contractility. AF patients with reduced LAA contractile fraction (LAAEF ≤21%) require strong anticoagulant therapy to avoid thromboembolic events regardless of a low CHADS2 score (≤1).
authors.affiliation: Department of Cardiology, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ono
authors.forename: Makoto
authors.initials: M
authors.lastname: Iwama
authors.forename: Masanori
authors.initials: M
authors.lastname: Kawasaki
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Tanaka
authors.forename: Takatomo
authors.initials: T
authors.lastname: Watanabe
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Onishi
authors.forename: Shunichiro
authors.initials: S
authors.lastname: Warita
authors.forename: Tai
authors.initials: T
authors.lastname: Kojima
authors.forename: Takashi
authors.initials: T
authors.lastname: Kato
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Goto
authors.forename: Masazumi
authors.initials: M
authors.lastname: Arai
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nishigaki
authors.forename: Genzou
authors.initials: G
authors.lastname: Takemura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Noda
authors.forename: Sachiro
authors.initials: S
authors.lastname: Watanabe
authors.forename: Shinya
authors.initials: S
authors.lastname: Minatoguchi
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology*; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology; D014463:Ultrasonography; D016277:Ventricular Function, Left / Q000502:physiology; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin