Gigantic coronary sinus associated with concurrent persistent left superior vena cava and right ventricular volume overload

A 76-year-old women with known atrial fibrillation and congestive heart failure presented with increasing shortness of breath. A 2-dimensional (2-D) transthoracic echocardiogram was performed to assess left ventricular function. An incidental finding of a very large coronary sinus with a diameter of 4.8 cm was seen, raising a suspicion for the possibility of a persistent left superior vena cava (PLSVC) (Figure 1). Additional pertinent positive findings included a massively dilated right atrium (estimated volume: 538 mL), dilated tricuspid annulus with poor leaflet coaptation, severe tricuspid regurgitation, and pulmonary artery systolic pressure (PASP) of 50 mmHg with an estimated mean right atrial pressure (RAP) of 25 mmHg. After agitated saline administration into the left brachial vein, there was immediate and sequential opacification of the dilated coronary sinus, right atrium, and right ventricle, confirming the presence of a PLSVC (Figure 2). CT angiography provided detailed anatomical and morphological characterization demonstrating drainage of the PLSVC into the gigantic coronary sinus and right-sided cardiac chambers and absence of other vascular or congenital anomaly (Figures 3 and 4).