A Rare Association of Patent Ductus Arteriosus (PDA) With Persistent Left Superior Vena Cava (PLSVC) and Unroofed Coronary Sinus (UCS) Terminating Into Left Atrium (LA): A Case Report of an Indian Infant.

Unroofed coronary sinus syndrome (UCSS), also named coronary sinus (CS) septal defect, is a rare type of atrial septal defect (ASD) with the incidence less than 1% of the total number of ASDs. It is caused by incomplete formation of left atrial venous folds during embryonic development. There is communication between the CS and left atrium (LA) due to the presence of a left superior vena cava (LSVC) along with an incomplete or complete loss of the CS roof draining into the LA. It usually presents as mild breathlessness on exertion and the appearance of murmurs on auscultation. A case that is diagnosed as an unroofed CS (UCS) related to a continuous LSVC terminating into the CS, which further terminates into LA, along with a large patent ductus arteriosus (PDA) is a rare presentation.