Lipomatous Interatrial Septum Detected During Cardioversion Evaluation for Atrial Fibrillation

Abstract

Primary cardiac tumors are rare, with an estimated prevalence in autopsy series ranging from 0,001 to 0,28%. Benign tumors are the most common type, with lipoma being the second most frequent among these, following myxoma. Lipoma can pose a differential diagnostic problem with lipomatous hypertrophy of the interatrial septum (IAS). This entity is rare and often asymptomatic, requiring no surgical treatment unless it causes obstruction of surrounding anatomical structures. In practice, cardiac CT and MRI are frequently used to confirm echocardiographic suspicions, both transthoracic and transesophageal. We present the case of a 72-year-old patient referred for management of recent atrial fibrillation, with heart rate control proving difficult despite maximum dose medical treatment. We opted for electrical cardioversion to improve the patient's hemodynamic state in the short term and to prevent progression to atrial cardiomyopathy in the medium and long term. In the transesophageal echocardiogram (TEE), the patient exhibited significant thickening of the interatrial septum, measuring 22 mm, without compression of the superior vena cava, and with the fossa ovalis remaining intact. Through this case, we discuss the diagnostic and therapeutic approaches to lipomatous hypertrophy of the IAS.