Identification and Analysis of Atrial-Bronchial-Abdominal Disharmony in Patients with Isomeric Atrial Appendages.

Ideally, the morphology of atrial appendages should solely be used to identify and differentiate patients with isomeric right and left atrial appendages. However, in clinical practice, the segregation is often indirectly based on the arrangement of thoraco-abdominal structures. The correlation between thoraco-abdominal arrangement and atrial appendages, however, is imperfect. In this study, we sought to clarify the cardiovascular malformations in patients with isomeric atrial appendages with an emphasis on atrial-thoracic-abdominal disharmony. A retrospective review of all patients who underwent cardiac CT angiography between January 2014 and June 2023 and identified to have isomeric atrial appendages was performed. Of the 366 cases (median age: 2 years [interquartile range: 11 months-7 years]), 247 (67.5%) patients had isomeric right atrial appendages while 119 (32.5%) patients had isomeric left atrial appendages. In 316 (86.3%) patients, the thoraco-abdominal arrangement was as per atrial appendage morphology while the remaining 50 (13.6%) patients had disharmonious patterns. Compared to isomeric left atrial appendages, the disharmonious pattern was more frequent with isomeric right atrial appendages (5.9% vs. 17.4%; p 0.003). Irrespective of the type of isomerism, disharmony was mostly confined to the level of the abdomen. Not all patients with isomeric atrial appendages have a harmonious thoraco-abdominal arrangement. The atrial-bronchial-abdominal disharmony is more frequent with isomeric right atrial appendages and is mostly present at the level of the abdomen. A detailed sequential segmental analysis with an independent description of each organ system is, therefore, essential for the complete evaluation of patients with isomeric atrial appendages.