ECG-Gated Dual-Source CT for Detection of Left Atrial Appendage Thrombus in Patients Undergoing Catheter Ablation for Atrial Fibrillation

J Interv Card Electrophysiol. 2010; 28(1):1123-1128

Kapa S, Martinez MW, Williamson EE, Ommen SR, Syed IS, Feng D, Packer DL, Brady PA

OBJECTIVES: 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.

PMID: 20809409

2 Responses

  1. Ronen Rubinshtein  on September 5th, 2010

    More data from this group describing excellent sensitivity for DSCT for exclusion of LAA thrombus in a large cohort of patients using TEE as the refernce standard.

  2. Jacobo Kirsch  on September 6th, 2010

    It appears that CT, either DSCT or MDCT with or without ecg-gating, is quite good at detecting LAA thrombus.

    Using nongated MDCT, this group showed a sensitivity and specificity of 100% and 92%, respectively, with a negative predictive value of 100% and positive predictive value of 23%. (link)


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