title: Left atrial appendage emptying fraction assessed by a feature-tracking echocardiographic method is a determinant of thrombus in patients with nonvalvular atrial fibrillation.
abstract: BACKGROUND
  Left atrial appendage (LAA) thrombus increases the risk of thromboembolism in atrial fibrillation (AF), and LAA contractile function like emptying fraction (EF) should have physiological importance in thrombus formation. The aim of this study was to validate a velocity vector imaging (VVI) method for quantification of the LAA function and to elucidate echocardiographic parameters that are related to the presence of LAA thrombus in patients with nonvalvular AF.
  
  
  METHODS
  We measured left atrial (LA) dimension and LAEF by VVI using transthoracic echocardiography, and LAA emptying velocity, spontaneous echo contrast (SEC), and LAAEF by VVI using transesophageal echocardiography (TEE) in 142 consecutive patients with nonvalvular AF. The patients were divided into two groups according to the presence (n=38) or absence (n=104) of LAA thrombus.
  
  
  RESULTS
  There was a good correlation between the VVI method and manual-tracing method for LAAEF and LAEF of patients with AF (r=0.97, r=0.96, respectively, p<0.001). LAAEF in AF with thrombus was significantly reduced compared with AF without thrombus (16.9±3.1% and 29.0±9.7%, p<0.001). In multivariate logistic regression analysis, LAAEF, SEC, and prior stroke were independent determinants of LAA thrombus. Using 20% of LAAEF as a cutoff value, the sensitivity was 92% and specificity was 88% for LAA thrombus.
  
  
  CONCLUSIONS
  The VVI method was reliable in the measurement of LAAEF and LAEF compared with the manual-tracing method. LAAEF assessed by the VVI method using TEE was related to the presence of LAA thrombus.
authors.affiliation: Department of Cardiology, Gifu Prefectural General Medical Center, Gifu, Japan.
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: Koji
authors.initials: K
authors.lastname: Ono
authors.forename: Takatomo
authors.initials: T
authors.lastname: Watanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Hirose
authors.forename: Maki
authors.initials: M
authors.lastname: Nagaya
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; D020517:Atrial Appendage / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000150:complications* / Q000000981:diagnostic imaging*; D004452:Echocardiography / Q000379:methods*; D017548:Echocardiography, Transesophageal / Q000379:methods; D005260:Female; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology*