A 25-year-old female presented with an intermittent palpitation. She got transthoracic echocardiography (TTE) 2 months ago at another hospital, after an episode of supraventricular tachycardia, which was reported as normal. Cardiovascular examination revealed a continuous murmur at the left 3rd intercostal spaces. Repeat TTE showed a tunnel-like structure from right coronary sinus on modified parasternal short axis images. The right atrium (RA) dimension was slightly increased. The pulmonary/systemic blood flow (Qp/Qs) ratio was estimated 2.0:1.0 by echocardiography. Cardiac CT was performed in order to characterize the anatomic specification of the tunnel, and showed the tunnel taking its origin from the aortic root and entering the RA. Coronary angiography revealed normal left coronary artery. There was a large tunnel-like structure beginning in the right coronary sinus, and terminating in the junction of superior vena cava (SVC) and RA (Figure). The tunnel showed aneurysmal dilatation, calcification and the right coronary artery (RCA) arose by the tunnel. Right heart catheterization confirmed the results of Qp/Qs shunt ratio as 2.0:1.0. Pulmonary artery systolic pressure was normal. In view of the substantial left-to right shunt and the predisposing risk for spontaneous rupture, surgical treatment was recommended. Aorta-right atrial tunnel is a rare congenital anomaly characterized by an extracardiac vascular communication arising from an aortic sinus and emptying into the RA. Closure of this anomaly is recommended because continued patency of the tunnel might predispose patient the risks of volume overload, aneurysm formation, or spontaneous rupture. Physical examination is an important part of the evaluation of a patient. Although TTE gives valuable information on the morphology of the heart, rare abnormalities cannot be noticed without clinical suspicion. The aorta-right atrial tunnel should be suggested in the clinical differential diagnosis of continuous murmur.
