One male case, 15 years old, weight 28 kg, one female case, 45 years old, 48 Kg, one male case on examination: cyanosis of lips, oxygen saturation of extremities measured 88-89%, heart rate 80 beats/min, grade II/6 blowing wind-like systolic murmur audible between 2 and 3 ribs at the left edge of the sternum, P2 mildly hyperactive, the rest negative. Electrocardiogram: sinus rhythm, non-deviated cardiac axis, incomplete right bundle branch block. Cardiac echocardiogram: complete absence of coronary sinus apical septum, sinus opening about 19 mm in the right atrium, left superior vena cava converging into the left atrium, estimated pulmonary artery systolic pressure 57 mm Hg. Cardiac 64-row CTA: left superior vena cava seen next to the aortic arch, converging directly into the left atrium, left The left atrial contrast enters the right atrium via the coronary sinus (the septum is visible with a maximum diameter of 18 mm), and there is no traffic between the left superior vena cava and the right superior vena cava. In one female, the echocardiogram was performed: the coronary sinus was completely absent in the apical septum, the sinus opening was about 22 mm in the right atrium, and the estimated pulmonary artery systolic pressure was 52 mm Hg. The procedures were performed under general anesthesia with moderate hypothermic extracorporeal circulation, and myocardial protection fluid was instilled via the aortic root and repeated every 30 minutes. After cardiac arrest, the sinusoidal defect of the coronary vein was revealed through a right atrial incision, and the sinusoidal defect of the coronary vein was repaired (with a polyester sheet) by repairing the primary orifice type defect, isolating the coronary vein opening into the left atrium, freeing the left superior vena cava in one case with a left superior vena cava, severing the left superior vena cava from the proximal end of the left superior vena cava, suturing the proximal end with 4-0 plonre suture, and using a 4 cm × 8 cm size autologous pericardial piece via A 4cm×8cm autologous pericardial piece was treated with 0.6%0 glutaraldehyde solution and sutured with 4-0plonre suture to form a tube of approximately 1.2 cm in diameter, which was anastomosed end-to-end with the proximal end of the left superior vena cava and the distal end with the right auricle. After cardiac resuscitation, the cardiac system was stopped, and the postoperative management was the same as that of ordinary cardiac surgery. Postoperative oxygen saturation was measured 93-94% (2262 m above sea level) without oxygen, and 2 patients recovered well. The postoperative electrocardiogram was sinus rhythm in 1, 3 and 6 months, and the echocardiogram showed no obstruction of the left superior vena cava reflux and no mitral regurgitation. Pang Yunfeng, Department of Cardiac Surgery, Qinghai Cardiovascular Hospital, China Discussion Coronary sinus syndrome without apex, also known as coronary sinus type septal defect, is relatively rare, due to incomplete formation of the left atrial vein wall during embryonic development, resulting in partial or complete defect of the top of the coronary sinus and its corresponding left atrial posterior wall, i.e., coronary sinus septum, thus causing the coronary sinus to communicate directly with the left atrium, forming a group of Comprehensive cardiac malformation. There are three types of coronary sinus defects according to the location and extent of the defect. Type I: complete coronary vein apical defect, in which the coronary sinus septum is completely absent and the coronary vein flows directly back into the left atrium with multiple openings. Type II: intermediate partial coronary vein apex defect, i.e., one or several garden-shaped or oval-shaped III coronary vein apex defects somewhere in the middle to upstream section of the coronary sinus septum, so that the coronary sinus communicates with both the left atrium and the right atrium. Type III: Terminal partial coronary sinus septal defect at the opening of the coronary sinus, often combined with an atrial septal defect, manifests as an opening of the coronary sinus in the left atrium, just below the posterior internal junction of the mitral valve. Once diagnosed, an apexless coronary sinus syndrome requires surgical treatment. However, the combination of the left superior vena cava and the presence of a patent innominate vein between it and the right superior vena cava plays a decisive role in the surgical approach. In cases where the left superior vena cava is not combined or is combined but can be ligated, only the coronary sinus type septal defect needs to be repaired, or the primary foramen type septal defect needs to be repaired leaving the coronary sinus opening in the left atrium. In cases where the left superior vena cava and the right superior vena cava lack a patent innominate vein and cannot be ligated, the following methods are usually used (1) intra-atrial plate barrier method: if an atrial septum exists, all the atrial septal tissue except the anterolateral septum is removed, and the septum is reconstructed with an autologous pericardial piece or artificial patch, and the superior and inferior vena cava and the left superior vena cava are septated into the right atrium and drained into the tricuspid valve; the pulmonary veins are septated into the left atrium and drained into the mitral valve. The pulmonary vein is septated into the left atrium and drains into the mitral valve. However, there is a possibility of obstruction of pulmonary vein and left superior vena cava reflux. (2) Supra-atrial pathway: The atrial septum is cut near the entrance of the superior vena cava, and a tunnel is made by an autologous pericardial piece or an artificial patch, which is extended from the entrance of the left superior vena cava along the left atrial apex to the upper part of the right atrium, and connected to the above cut atrial septum to close the interatrial traffic. (3) Coronary sinus apex reconstruction method: A new sinus apex is made with an autologous pericardial piece or a fold of atrial coin. Care is taken to avoid obstruction of the left superior vena cava and vena cava reflux when suturing, and to avoid damage to the conduction bundle. (4) Extracardiac method: The left superior vena cava is cut at the proximal atrium, and the proximal end is sutured closed to connect the distal end to the right auricle. If the length of the left superior vena cava is not sufficient, a PTEE artificial vessel can be used. Contraindications are those with Eisenmenger syndrome due to combined cardiac malformations. We repaired the coronary sinus defect (with a polyester-taki piece) by repairing the primary foramen ovale defect, isolated the coronary vein opening into the left atrium, and used the extracardiac method to connect the left superior vena cava to the right auricle with a conduit made from an autologous pericardial piece, which compensated for the lack of length of the left superior vena cava and simplified the complicated operation, avoiding obstruction of vena cava return and achieving a good therapeutic result.