title: Incidence and predictors of left atrial thrombus prior to catheter ablation of atrial fibrillation.
abstract: BACKGROUND
  Transesophageal echocardiography (TEE) is commonly used prior to catheter ablation of atrial fibrillation (AF) in order to exclude left atrial (LA) thrombus. However, the incidence and predictors of LA thrombus detected with TEE have not been systematically examined in this setting.
  
  
  METHODS
  This study included 732 cases (mean age 57 +/- 11 years; 23% female; 353 persistent AF) in 585 consecutive patients referred for catheter ablation of AF. Patients were anticoagulated for at least 4 weeks prior to the procedure and then bridged with enoxaparin. TEE was performed in all cases within 24 hours prior to ablation.
  
  
  RESULTS
  Preprocedural TEE revealed LA thrombus in 12 of 732 cases (1.6%), all located in the LA appendage. Among these 12 patients, 9 had persistent AF and 3 had paroxysmal AF. All patients with thrombus had an LA size >or= 4.5 cm. LA thrombus was present in 0.3%, 1.4%, and 5.3% of patients with CHADS(2) scores of 0, 1, and >or= 2, respectively. In multivariate analysis, a CHADS(2) score >or= 2 and larger LA diameter remained significant predictors of LA thrombus.
  
  
  CONCLUSIONS
  Despite oral anticoagulation treatment, there is a small but significant incidence of LA thrombus by TEE prior to AF ablation. A CHADS(2) score >or= 2 and larger LA diameter are independent predictors of LA thrombus in this patient population, while type of AF or rhythm at the time of TEE is not. The risk of LA thrombus is low in patients with a CHADS(2) score of 0 and in patients with an LA diameter < 4.5 cm.
authors.affiliation: Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Scherr
authors.forename: Darshan
authors.initials: D
authors.lastname: Dalal
authors.forename: Karuna
authors.initials: K
authors.lastname: Chilukuri
authors.forename: Jun
authors.initials: J
authors.lastname: Dong
authors.forename: David
authors.initials: D
authors.lastname: Spragg
authors.forename: Charles A
authors.initials: CA
authors.lastname: Henrikson
authors.forename: Saman
authors.initials: S
authors.lastname: Nazarian
authors.forename: Alan
authors.initials: A
authors.lastname: Cheng
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Berger
authors.forename: Theodore P
authors.initials: TP
authors.lastname: Abraham
authors.forename: Hugh
authors.initials: H
authors.lastname: Calkins
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage; D001281:Atrial Fibrillation / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D006328:Cardiac Catheterization; D017115:Catheter Ablation; D017548:Echocardiography, Transesophageal; D017984:Enoxaparin / Q000008:administration & dosage; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome; D014859:Warfarin / Q000008:administration & dosage
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D014859:Warfarin