Anomalous Left Atrial Band With Atrial Septal Defect

A 55-year-old woman was referred to hospital for transcatheter closure of an atrial septal defect (ASD). The preprocedural transesophageal echocardiogram revealed an abnormal band-like structure in the left atrium (Figure A), which contrast-enhanced computed tomography (CT) confirmed was extending from the posterior defect rim to the left atrial roof (Figure B–D). Given the potential for interference with a transcatheter closure device, the heart team decided to perform surgical closure. During surgery, an anomalous band leading from the defect rim to the left atrial roof was identified and resected (Figure E,F). The pathological findings revealed fibrous tissue composed of dense collagen fibers with a surface covering of a single endothelial layer.

Figure.

(A) Transesophageal echocardiogram shows the anomalous left atrial band (arrow). (B–D) Short-axis, coronal, and 3D contrast-enhanced CT images show the band connecting the interatrial septum and left atrial roof (arrows). (E) During surgery, the band visible through the atrial septal defect (ASD; arrow) and (F) resected. LA, left atrium; RA, right atrium.

Anomalous left atrial band is a rare congenital anomaly reported in 2% of autopsy cases, characterized by a pathology composed of fibrous or fibromuscular tissues.¹ It often coexists with patent foramen ovale (PFO) and Chiari network, but there are no reported cases of concomitant ASD. Because the band typically connects the fossa ovalis to the other wall of the left atrium, it should be identified as a complication of ASD or PFO, which have indications for closure. From a clinical standpoint, the band may interfere with transcatheter closure devices, potentially leading to procedural failure or complications. Furthermore, improper placement of the closure device may result in residual shunts, thrombosis, or device dislodgement. Surgical closure should be considered in such cases.

Disclosures

Y.S. is a member of Circulation Journal’s Editorial Team. The other authors declare no conflicts of interest.

Data Availability

The deidentified participant data will not be shared.

Reference

• 1.   Yamashita T, Ohkawa S, Imai T, Ide H, Watanabe C, Ueda K. Prevalence and clinical significance of anomalous muscular band in the left atrium. Am J Cardiovasc Pathol 1993; 4: 286–293.