Partially unroofed coronary sinus and persistent left superior vena cava: intracardiac echocardiographic observation.

Unroofed coronary sinus, a rare congenital anomaly first described by Raghib and colleagues1 in 1965, is a result of an embryologic error involving imperfect or complete failure of development of the left atriovenous fold, which is manifested as a focal (fenestration or partial unroofing of the coronary sinus) or complete absence of the coronary sinus septum. Before the era of echocardiography, precise diagnosis of this anomaly was possible only...