Uncommon presentation of coronary sinus endocarditis.

A 79-year-old man, who underwent femoropopliteal bypass surgery 1 month prior to admission, presented with fever and fatigue. ECG showed complete atrioventricular block. Transthoracic echocardiography was performed, revealing a round homogeneous right atrial mass and severe mitral regurgitation. Transoesophageal echocardiography revealed involvement the coronary sinus (CS). Computed tomography imaging demonstrated abscess of the atrioventricular sulcus and infiltration of the CS.