Left atrial anomalous bands associated with arrhythmia detected by computed tomography during coronary CT angiography: a case series

False tendons are fibrous cord-like malformations within the cardiac chambers, with only approximately 2% occurring in the left atrium. In this study, we analyzed the clinical and imaging characteristics of multiple cases of left atrial false tendons (LAFTs) to provide additional clinical insights into this uncommon anatomical variant. A total of 10 representative LAFTs cases identified between September 2015 and June 2022 were included in this analysis. All patients were diagnosed using coronary computed tomographic angiography (CCTA). A retrospective analysis was performed using data retrieved from the Radiology Information System (RIS) and Picture Archiving and Communication System (PACS). Clinical history and electrocardiographic data were reviewed, and Xelis software was used for three-dimensional reconstruction to evaluate the morphology, anatomical position, and length of the LAFTs. Among the patients, eight exhibited arrhythmias: five had coarse, short longitudinal muscle bundles associated with atrial premature beats, while three had delicate longitudinal bundles accompanied by nonspecific T-wave abnormalities. The remaining two patients showed no specific symptoms or arrhythmic findings. Imaging analysis revealed that longitudinal and transverse muscle bundles measured approximately 2.5-3.0 cm and 3.5-4.4 cm in length, respectively, with attachments commonly located between the anterior and posterior walls of the left atrium or between the interatrial septum (near the fossa ovalis) and the lateral wall. A potential correlation between LAFTs and electrocardiographic abnormalities was observed. These findings suggest that LAFTs may be considered in the differential diagnosis when evaluating patients with unexplained arrhythmias undergoing CCTA.