Introduction
UCSS is a group of rare, complex cardiac malformations caused by the absence of left atrial venous plica during the development of the embryo, that is, the partial or complete defect of coronary sinus (CS) septum, which lead to direct communication between CS and the LA. UCSS is often associated with LSVC (80% to 90%), whose overall incidence is about 0.3% to 0.5%, and incidence in congenital heart diseases is about 3% to 10%[1]. Preoperative diagnosis used to be difficult because of the lack of specific clinical manifestations and examination methods of UCSS. From May 1998 to May 2019, we treated 68740 cases of congenital heart diseases, including 159 cases of UCSS (0.23%), which treated by different methods of operation and achieved good effects. This paper is to summarize the clinical characteristics and surgical treatment experience, and to provide reference for the preoperative diagnosis and treatment of such diseases in the operation, in order to improve the curative effect