An Electrophysiological and Anatomical Space-Occupying Lesion: Lipomatous Hypertrophy of the Interatrial Septum in a Patient Presenting with Atrial Tachycardia

Lipomatous hypertrophy of the interatrial septum (LHIS) rarely causes clinical sequelae and is often reported as an incidental finding on cardiac imaging. Arrhythmia is an unusual complication of LHIS, although other tumors have been reported to cause arrhythmias by mass effect or tissue invasion.1 We present an unusual case of atrial arrhythmias associated with a large atrial mass that was subsequently confirmed to be LHIS.