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Updated: Aug 11, 2026
The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Impact of left atrial appendage thrombus location on diagnostic accuracy of cardiac CT: a single-centre case-control
Chuxian Guo1,2, Zhi Jiang1, Jionghong He1,3
1Cardiology Department, Guizhou Provincial People's Hospital, Guiyang, Guizhou, China.
Insights
Cardiac CT (CCT) shows lower sensitivity than TEE for detecting left atrial appendage (LAA) thrombi, particularly smaller, faster-moving LAA-ostium thrombi. This impacts atrial fibrillation ablation planning.
Area of Science:
- Cardiology
- Radiology
- Medical Imaging
Background:
- Left atrial appendage (LAA) thrombus is a risk factor for stroke in atrial fibrillation patients.
- Cardiac CT (CCT) is an emerging non-invasive tool for LAA thrombus detection.
- Conflicting results exist regarding CCT accuracy for LAA thrombus.
Purpose of the Study:
- To evaluate the diagnostic accuracy of CCT for detecting LAA thrombus.
- To compare CCT with trans-oesophageal echocardiography (TEE) as the reference standard.
- To identify factors influencing CCT accuracy in patients undergoing atrial fibrillation catheter ablation.
Main Methods:
- A case-control study involving 726 patients undergoing catheter ablation for atrial fibrillation.
- Both CCT (angiographic and 30s delayed scan) and TEE were performed.
- LAA thrombi defined by TEE (mass) or CCT (defect); dimensions, location, and LAA flow velocity assessed by TEE.
Main Results:
- TEE identified LAA thrombi in 7.9% of patients (n=57).
- CCT detected 48.3% of LAA-ostium thrombi but 89.3% of intra-LAA thrombi (p=0.001).
- LAA-ostium thrombi with high flow velocity (>0.35 m/s) and small size (<10 mm) were frequently missed by CCT.
Conclusions:
- CCT with a 30s delay scan has lower sensitivity than TEE for LAA thrombi.
- CCT is less effective for detecting LAA-ostium thrombi, especially when small and mobile.
- TEE remains crucial for comprehensive LAA thrombus assessment prior to atrial fibrillation ablation.
Objective:
Cardiac CT (CCT) is an emerging non-invasive modality for assessing left atrial appendage (LAA) thrombus, but the results were conflicting. Our study aims to evaluate the accuracy of CCT for detecting LAA thrombus in patients undergoing catheter ablation of atrial fibrillation, using trans-oesophageal echocardiography (TEE) as the reference standard.
Design:
Case-control study.
Setting:
Patient data were collected from a tertiary hospital in China between 2017 and 2022.
Participants:
The study enrolled 726 patients (male: 60.2%, age: 61±11 years) who had both TEE and CCT before catheter ablation of atrial fibrillation.
Measures:
The CCT protocol consisted of one angiographic phase and one delayed scan 30 s later. LAA thrombi were defined as solid masses on TEE or persistent defects on CCT. The thrombus dimension and location, the LAA filling and emptying flow velocity were assessed by TEE.
Results:
Of the 57 (7.9%) patients with LAA thrombi identified by TEE, 29 (50.9%) were located at the LAA ostium, and 28 (49.1%) were in the LAA. The former showed higher motility following blood flow and heartbeats than the latter. The CCT detected 14 (48.3%) of the LAA-ostium thrombi but 25 (89.3%) of those in the LAA (p=0.001). The LAA-ostium thrombi with the LAA mean flow velocity >0.35 m/s and maximum diameters <10 mm were more prone to have CCT false-negative results.
Conclusion:
For patients undergoing catheter ablation for atrial fibrillation, CCT with a 30 s delay scan is less sensitive to LAA thrombi than TEE, especially for LAA-ostium thrombi with smaller sizes and higher LAA flow velocity.
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