Implantation of a Cardiac resynchronization therapy system in a patient with an unroofed coronary sinus

The unroofed coronary sinus (URCS) is a spectrum of cardiac anomalies in which part or all of the common wall between the coronary sinus and the left atrium is absent. Rarely, it is associated with coronary sinus atresia. The diagnosis of this lesion is important for the prognosis of the patient, especially in cases when cardiac interventions such as CRT implantation needs to be performed. It is found incidentally because of nonspecific clinical features. We report a case of a complete URCS and CS atresia during a computed tomographic investigation performed following prior impossibility of LV lead to be implanted.