Abstract 13210: A Hidden Right Atrial Lipoma in a Patient With Recurrent Sustained Supraventricular Tachycardias

Abstract

Introduction: Cardiac lipomas, known for their benign nature, compose 8 percent of primary cardiac tumors. Advanced imaging modalities allow improved diagnosis, yet little of their potential complications involving the heart's conduction system is known. Case: A 65-year-old male presented to the Emergency Department with palpitations. History was significant for recurrent sustained orthodromic atrioventricular reentrant tachycardia using a concealed left posterior accessory pathway from a prior EP study. He was treated with ablation twice in the past. The patient was hemodynamically stable on evaluation. ECG showed supraventricular tachycardia (SVT) involving orthodromic re-entry with a ventricular rate of 227 bpm. Computer tomography (CT) of the chest revealed a large, low-attenuated lesion with -102 Hounsfield unit (HU) attached to the right atrial roof, extending to both SVC and IVC. No sparing of foramen ovale was seen. Findings suggest right atrial lipoma. A transthoracic echocardiogram (TTE) visualized the same echo-dense structure without increased vascularity. The patient responded to intravenous Adenosine. We discussed the case with the Cardiothoracic surgery team. Outpatient cardiac MRI and elective surgery were planned. Discussion: The case presented clinically significant atrial arrhythmia in a patient with a massive right atrial lipoma. Although most cardiac lipomas remain asymptomatic, arrhythmias coinciding with the location of involved chambers have been reported. In addition, the recurrence of orthodromic tachycardia despite previous ablation suggests the potential benefit of surgical intervention.