CASE PRESENTATION: A 45-year-old woman with a past medical history of uterine sarcoma resection complicated by chronic right hydronephrosis and a chronic stent, a recent deep vein thrombosis and massive pulmonary embolism requiring surgical embolectomy and chronic anticoagulation, presented with increasing dyspnea on exertion and palpitations. Initial assessment including vital signs showed blood pressure of 132/80mmHg, heart rate 115 beats/min and respiratory rate of 18/min. Cardiovascular examination revealed absent jugular venous distension, a new pan-systolic non-radiating grade II/VI murmur at the mitral area, faint S1, S2 and bilateral clear breath sounds. An electrocardiogram revealed sinus tachycardia with no ischemic changes. An urgent transthoracic echocardiogram demonstrated a possible membranous ventricular septal defect. This warranted a trans-esophageal echocardiogram (TEE) which surprisingly revealed left to right shunt with systolic and diastolic flow between the right sinus of Valsalva and the right atrium. This was consistent with aorto-atrial fistula. She underwent emergent successful redo sternotomy and closure of the fistula with no postoperative complications.