Misdiagnosis of aorta-right atrial tunnel.

First reported by Coto in 1980, aorta-right atrial tunnel (ARAT) is a rare congenital vascular connection between the aortic root and RA. The case report presents a 38-year-old male patient with ARAT. Echocardiography showed a tunnel-like structure which appeared to be a connection between the left coronary sinus and the left atrium although the tunnel was connected to the right atrium. The misdiagnosis may be explained that the images were overlaid and abnormal color flow signal was not detected in RA because of the failure to detect color flow spectrum at the outlet of superior vena cava (SVC). We have discussed the diagnostic experience of the rare congenital cardiac anomaly in echocardiography: (1) carefully detect the origin and termination of abnormal tunnel structure; (2) the outlet of SVC into RA should be detected for possible artery flow spectrum and color flow signal into RA; (3) transesophageal echocardiography should be performed for identifying the diagnosis of ARAT if it is necessary.