Congestive heart failure (CHF) due to high output states is known to occur in a variety of systemic illnesses and in patients with arterial-venous fistulas. This paper reports the case of a 45-year-old man admitted to the emergency room with a diagnosis of new onset atrial fibrillation and CHF, whose past medical history was not significant except for a gunshot wound to his abdomen 22 years previously. The etiology of his CHF together with the cardiomegaly and hyperdynamic left ventricular systolic function was unknown. A subcostal view routinely done during transthoracic echocardiography revealed a severely dilated inferior vena cava and the presence of an aorto-caval fistula by color doppler. The patient underwent successful corrective repair with dramatic improvement in symptoms and resolution of the atrial fibrillation, and cardiac size returned to normal. This rare case emphasizes that patients with refractory CHF must be closely examined with particular attention to palpation and auscultation over all scars, irrespective of the duration since any traumatic or surgical event.