3 ︱ DISCUSSION
Of all types of CAF, giant left coronary aneurysm with right atrium fistula is uncommon 4. It has been reported that 90% of CAF originated from the right coronary artery, of which only 0.2% were giant coronary aneurysms (> 4 times of the normal diameter) 5. CAF often has no specific clinical manifestations, with or without angina pectoris and cardiac murmur, which is closely affected by the location and size of the fistula. The optimal treatment for CAF remains controversial, the most common approaches are transcatheter closure of the fistula, surgical resection of the aneurysm, and bypass grafting of the coronary artery. Multimodal imaging and functional testing play vital roles in the diagnosis of CAF. Specially, coronary angiography and cardiac CT are universal methods for diagnosing and tracking the anatomical abnormalities of coronary. However, coronary angiography is invasive, and CT often misses tiny breaks. In this study, we proved that TTE and TEE are necessary and sufficient to determine the complex anatomy of coronary fistula and its relationship to adjacent structures, and can be used for preoperative, intraoperative, and postoperative assessments. Echocardiography has the advantages of non-invasive, real-time, and inexpensive, especially in detection of the rupture and location of fistula by color Doppler. It is worth noting that the echocardiographic images in this case need to be differentiated from the three-atrial heart, and the apical four-chamber view of TTE may easily mistake the aneurysm wall for the right atrial septum and the fistula for the septal hole.