title: ECG-gated dual-source CT for detection of left atrial appendage thrombus in patients undergoing catheter ablation for atrial fibrillation.
abstract: OBJECTIVE
  Left atrial ablation is increasingly used to treat patients with symptomatic atrial fibrillation (AF). Prior to ablation, exclusion of left atrial appendage (LAA) thrombus is important. Whether ECG-gated dual-source computed tomography (DSCT) provides a sensitive means of detecting LAA thrombus in patients undergoing percutaneous AF ablation is unknown. Thus, we sought to determine the utility of ECG-gated DSCT in detecting LAA thrombus in patients with AF.
  
  
  METHODS
  A total of 255 patients (age 58 ± 11 years, 78% male, ejection fraction 58 ± 9%) who underwent ECG-gated DSCT and transesophageal echocardiography (TEE) prior to AF ablation between February 2006 and October 2007 were included. CHADS2 score and demographic data were obtained prospectively. Gated DSCT images were independently reviewed by two cardiac imagers blinded to TEE findings. The LAA was either defined as normal (fully opacified) or abnormal (under-filled) by DSCT.
  
  
  RESULTS
  An under-filled LAA was identified in 33 patients (12.9%), of whom four had thrombus confirmed by TEE. All patients diagnosed with LAA thrombus using TEE also had an abnormal LAA by gated DSCT. Thus, sensitivity and specificity for gated DSCT were 100% and 88%, respectively. No cases of LAA filling defects were observed in patients <51 years old with a CHADS2 of 0.
  
  
  CONCLUSIONS
  In patients referred for AF ablation, thrombus is uncommon in the absence of additional risk factors. Gated DSCT provides excellent sensitivity for the detection of thrombus. Thus, in AF patients with a CHADS2 of 0, gated DSCT may provide a useful stand-alone imaging modality.
authors.affiliation: Division of Cardiology, Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Suraj
authors.initials: S
authors.lastname: Kapa
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Martinez
authors.forename: Eric E
authors.initials: EE
authors.lastname: Williamson
authors.forename: Steve R
authors.initials: SR
authors.lastname: Ommen
authors.forename: Imran S
authors.initials: IS
authors.lastname: Syed
authors.forename: DaLi
authors.initials: D
authors.lastname: Feng
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.forename: Peter A
authors.initials: PA
authors.lastname: Brady
mesh_terms: D020517:Atrial Appendage; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000601:surgery*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017115:Catheter Ablation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013927:Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000517:prevention & control; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
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