Isolated absence of coronary sinus: two cases report.

Coronary sinus (CS) is the venous drainage system of the heart. Absence of the coronary sinus or atresia of ostium of the CS are rarely seen cardiac malformations. Congenital absence of CS usually is found together with other cardiac malformations, however, isolated congenital absence of CS is very rare. Multiple coronary-cameral fistulous connections, through which the blood drains into one of the cardiac chambers, are commonly seen in patients with CS abnormalities. Herein we present a case two cases of total absence of CS with a venous system draining directly into the left ventricle through Thebesian veins.