Detection of Left Atrial Appendage Thrombus by Cardiac Computed Tomography in Patients With Atrial Fibrillation: A Meta-Analysis

Study Questions:

What is the accuracy of cardiac computed tomography (CCT) to identify left atrial/left atrial appendage (LAA) thrombus as compared to transesophageal echocardiography (TEE)?


This meta-analysis examined the diagnostic accuracy of CCT to identify LAA thrombus as compared to TEE as a reference standard. Studies were included if both TEE and CCT were done within 7 days; the studies were performed to evaluate potential LAA thrombus in patients with atrial fibrillation prior to ablation or cardioversion procedures, or as part of a stroke evaluation; and calculation of diagnostic accuracy was available. A total of 19 studies that included 2,955 patients met inclusion criteria and were included in the analyses.


Mean age was 61 ± 4 years and 71% were male. The incidence of LAA thrombus was 9 ± 7%. Studies were performed prior to atrial fibrillation ablation procedures (n = 11) or cardioversion procedures (n = 1), or to evaluate patients following stroke (n = 7). The mean sensitivity, specificity, positive predictive value, and negative predictive values of CCT as compared to TEE were 96%, 92%, 41%, and 99%, respectively, with an overall accuracy of 94%. In a subgroup of seven studies that include delayed imaging, the mean accuracy was 99%, and the sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 99%, 92%, and 100%, respectively.


CCT may represent an accurate means to identify LAA thrombus, and this accuracy improves with the use of delayed CCT imaging.


This meta-analysis demonstrates that CCT may represent an accurate method to identify LAA thrombus in patients with atrial fibrillation or possible embolic stroke. CCT has an advantage in that it is noninvasive, and it may be particularly helpful in patients with a nondiagnostic TEE or with contraindication to TEE. Nevertheless, CCT is associated with its own risks, including a need for iodinated contrast and exposure of the patient to ionizing radiation. While these findings are promising, before CCT can be considered a standard alternative to TEE, studies are needed that examine the clinical outcomes following CCT evaluation of the left atrium and appendage in these patients.

Clinical Topics: Arrhythmias and Clinical EP, Noninvasive Imaging, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound

Keywords: Heart Diseases, Stroke, Radiation, Ionizing, Atrial Appendage, Thrombosis, Cardiology, Electric Countershock, Catheter Ablation, Echocardiography, Transesophageal

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