Accurate sizing of the left atrial appendage (LAA) is essential for selecting the appropriate device during percutaneous LAA occlusion procedures and for planning electrophysiology interventions.

Transesophageal echocardiography (TEE) is commonly used during procedures because of its excellent temporal resolution and ability to visualize the appendage. However, its semi-invasive nature and limited foreshortening can affect measurement accuracy.

Multidetector computed tomography (CT) offers high spatial resolution and the ability to perform true-orthogonal reformatting, which allows for precise assessment of complex LAA anatomy. CT measurements, however, can be influenced by factors such as the timing of the contrast bolus and cardiac phase (Sattar Y et al., 2022).

This prospective, blinded study compares TEE with contrast-enhanced CT for assessing LAA dimensions. The primary endpoint is the agreement between the two modalities in measuring the LAA ostium diameter and appendage depth. This is analyzed using Bland-Altman analysis, with CT serving as the spatial reference due to its high isotropic resolution (Soh BWT et al., 2024).

Secondary endpoints include comparing LAA morphological subtypes and location classification between the two imaging methods.

We will enroll adult patients who are already scheduled for routine TEE and a prescribed cardiac CT. Eligible participants will receive an additional contrast-enhanced cardiac CT at no cost, performed during the same clinical visit or within 48 hours to avoid anatomical changes.

Two independent readers, each focused on a specific imaging modality and blinded to each other’s results and clinical data, will measure the LAA ostium diameter and depth using predefined anatomical landmarks. All data will be securely stored for later statistical analysis, allowing a direct comparison of imaging results and an evaluation of TEE performance under blinded conditions.