Unroofed coronary sinus syndrome is an uncommon anomaly, Unroofed coronary sinus syndrome is caused by incomplete formation of the left atriovenous fold, and it usually is associated with Left SVC. If it is not diagnosed, a residual reversed or bidirectional shunt will result, and its complications will reduce life expectancy. We experienced 3 cases of unroofed coronary sinus syndrome which combines TOF with PLSVC, partial ECD, primum type ASD. In case of Unroofed coronary sinus syndrome which combines TIF with PLSVC, preoperative diagnosis was not made. In corrective operation for TOF of this case, pump weaning was failed due to hypoxia and cardiac arrest, and he expired at operation room. At autopsy of this case, complete unroofed coronary sinus was found. In the other 2 cases, partial unroofed coronary sinus syndrome was found in operation field and corrective operation was performed successfully. We report these 3 experiences with its review. ^u ++ Noninvasive Assessment of Pressure Gradients across Prosthetic Heart Valve by Doppler Ultrasound - A comparative study of the Duromedics Bileaflet Valves in mitral position and Normal Mitral Valves -with its review.