Giant coronary sinus and absent right superior vena cava.

Although persistent left superior vena cava (PLSVC) is rare, it is the most common thoracic venous anomaly. The prevalence of PLSVC is 0.3 % in a general population and 10 % in patients with congenital heart disease. Diagnosis of PLSVC is usually incidental during cardiovascular imaging or surgery. Although PLSVC is usually not associated with any negative hemodynamic effect, it is important to be aware of its existence, since it may cause problems in central venous catheterization, pacemaker implantation and cardiopulmonary bypass. The overall proportion of absent right superior vena cava in patients with PLSVC is approximately 20 %. If PLSVC is associated with absence of the right superior vena cava, the coronary sinus may become gigantic due to excessive inflow. Herein, we report a case of PLSVC complicated by the absence of a right superior vena cava resulting in a giant coronary sinus.