This investigation is a prospective, blinded comparison study in which adult patients (more than 18 years)  requiring evaluation for left atrial appendage (LAA) thrombus will undergo both Transesophageal Echocardiography (TEE) and Contrast Cardiac CT as per standard of care. Patients are enrolled following confirmation that they meet inclusion criteria, such as having atrial fibrillation and being suitable candidates for both TEE and CT. After informed consent is obtained, TEE is performed under routine clinical conditions. Subsequently, within a defined interval to minimize clinical changes, patients receive a Contrast Cardiac CT according to standardized cardiac imaging protocols. The TEE interpreter is blinded to the CT findings, while the CT images are evaluated by a separate cardiac imaging specialist unaware of TEE results.

The primary endpoint is the accuracy, sensitivity and specificity of TEE in detecting LAA thrombus, using CT as the reference standard. The sole secondary endpoint included in this study is correlating the anatomical types and location of the left atrial appendage (LAA) identified by TEE with those observed on CT, thereby assessing the consistency of structural characterization between the two modalities. All relevant findings are captured in a secure database for subsequent statistical analysis, enabling a direct comparison of imaging results and a clear evaluation of TEE performance under rigorous, blinded conditions.