Key Clinical Message:
The association of UCSS with PLSVC must be kept in mind during operation. Creating an intra-atrial tunnel to divert the flow of PLSVC into RA, without obstructing the mitral valve or the pulmonary veins, is a safe surgical approach.
Introduction :
Persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly, with an incidence of 0.2% in normal neonates (1). However; it is more common among patients with congenital heart diseases (CHD) (1.4%), and recognition of its presence by preoperative diagnosis is of a great importance during congenital heart surgery (1-4). Commonly, PLSVC drains into the right atrium (RA) via the coronary sinus (CS), and when isolated, it is usually asymptomatic, and may be detected incidentally (1). Unroofed coronary sinus syndrome (UCSS) is an uncommon CHD which leads to a left to right shunt at the atrial level, and comprises <1% of all atrial septal defect (ASD) types (2, 5). When UCSS is associated with PLSVC, it is difficult to detect the diagnosis by transthoracic echocardiography (TTE) (1). Herein, we present a case of a 2-year-old patient with preoperative diagnosis of coronary sinus-type ASD; however, PLSVC draining into the left atrium (LA) was detected during surgery.