A case of right atrial appendage aneurysm mimicking a pericardial cyst on echocardiogram

Right atrial appendage aneurysms (RAAAs) are rarely encountered. If symptomatic, they present with atrial arrhythmias or embolic events. Surgical resection is indicated for symptomatic patients. We describe a 65-year-old man presenting with palpitation for 6 months. Electrocardiogram showed atrial flutter. Transthoracic echocardiography revealed a large thin-walled cystic mass anterior to right ventricular outflow tract, which was confirmed to be a giant RAAA by contrast transoesophageal echocardiography and later by contrast-enhanced computerised tomography. The patient underwent electrocardioversion, following which he remained in sinus rhythm and was asymptomatic during the 3 months follow-up period. LEARNING POINTS: RAAA can present with atrial flutter. Transoesophageal contrast echocardiography is the most valuable non-invasive tool in diagnosis of RAAA. Although computed tomography scan is not necessary for establishing the diagnosis, it may provide useful information regarding the structural anatomy.