A congenital cardiovascular malformation in which there is direct communication between the left atrium and the coronary sinus.
Additional information: this term includes partial and complete unroofing of the coronary sinus in the presence or absence of an interatrial communication. If an interatrial communication is present through the coronary sinus orifice then also select the term 'Interatrial communication through coronary sinus orifice'. If a left superior caval vein (superior vena cava) is present then one should also select the term for 'Left superior caval vein (superior vena cava) to left-sided atrium'.
Coding note
If an interatrial communication is present through the coronary sinus orifice code also interatrial communication through coronary sinus orifice. If a left superior caval vein (superior vena cava) is present code also left superior caval vein (superior vena cava) to left-sided atrium.