Idiopathic Extremity Arteriovenous Fistula: A Rare Etiology of Cardiac Failure

Idiopathic extremity arteriovenous fistulas are rare, abnormal connections between arteries and veins commonly occurring between iliac vessels. We present the case of a 42-year-old female who was referred to our center for a mitral valve replacement with a one-year history of breathlessness and a six-month history of progressive abdominal distension. Physical examination revealed a pansystolic murmur in the mitral area, basal crepitations, and a non-tender pulsatile swelling in the right iliac fossa. Imaging showed severe mitral regurgitation in heart failure along with a large arteriovenous fistula between the common femoral vessels which suggested that the arteriovenous fistula was the etiology of heart failure. Postoperatively, the patient showed significant improvement in symptoms with imaging. On follow-up, the patient reported no progression of symptoms. Our case demonstrated an idiopathic extremity arteriovenous fistula in an unusual location, unexpectedly causing heart failure despite a significant valvular disease. Therefore, arteriovenous fistulas warrant inclusion in the differential of heart failure despite a valvular lesion and absence of classical signs of high output heart failure, as in our case.