Multimodality imaging of an asymptomatic giant right atrial appendage aneurysm.

Right atrial appendage (RAA) aneurysm is a rare congenital cardiac abnormality thought to be caused by dysplasia of the muscular wall of the RA and RAA. Structural, contractile, or electrical atrial changes are associated with the onset and progression of atrial fibrillation. The RAA aneurysm can have various symptoms, such as thromboembolic complications. Diagnosis of RAA aneurysm greatly depends on imaging modalities, among which echocardiography is the most widely used one. Echocardiography is very effective in discovering the aneurysm, distinguishing it from other abnormalities such as pericardial cysts, Ebstein's anomaly and cor triatriatum, and detecting intracardiac thrombosis or blood flow limitations. Cardiac magnetic resonance imaging and computed tomography are important complementary examinations. They may provide more details on the neighboring structures of the aneurysm, especially when echocardiographic images are suboptimal.