Heart failure due to giant congenital aorto-right atrial fistula: report of a case.

Coronary arterio-venous fistula (CAVF) is a rare coronary artery anomaly. We demonstrated the rare findings of a large congenital aorto-right atrial fistula with initial presentation of heart failure symptoms. Transthoracic echocardiography and transesophageal echocardiography made the accurate diagnosis. Further haemodynamic and angiographic study proved this large CAVF with extraordinary oxygen saturation step-up (26%) and large pulmonary to systemic shunt (Qp/Qs = 4.25). It was corrected by surgery because of evidence of heart failure and the possible risk of endocarditis and coronary steal effect.