Abnormal coronary sinus morphology Coronary sinus enlargement 2017-08-13T21:47:43Z The coronary sinus is rarely seen on echocardiography in healthy persons. The differential diagnosis of dilated coronary sinus includes right ventricular dysfunction, right atrial hypertension, and anomalous venous drainage into the coronary sinus. Abnormal increase in size of the coronary sinus. Coronary sinus dilatation Enlarged coronary sinus