Unusual Communication between the Pulmonary Artery and Vieussens' Arterial Ring Causing Infective Endocarditis.

Coronary artery fistula is an abnormal communication between the coronary artery and the cardiac chambers. In particular, an abnormal connection between the conus branch of the right coronary artery and the proximal left anterior descending coronary artery is defined as Vieussens' arterial ring. Coronary artery fistulas are usually asymptomatic, but some can cause complications such as infective endocarditis. Here, we report a case of Vieussens' arterial ring causing infective endocarditis with severe mitral regurgitation.