The occurrence of an arteriovenous fistula is a potential complication of cardiac catheterization. Most of these fistulas cause no harm. We report the clinical case of a 70 years old woman with high-output heart failure caused by an arteriovenous fistula (FAV) in the groin. The fistula was successfully closed by surgical repair and the heart failure was resolved. This case confirms the potential harmfulness for the vascular bed of certain surgical/endovascular interventions and intravascular monitoring techniques. When heart failure of uncertain etiology appears in patients previously submitted to one of the above mentioned procedures, a careful clinical examination can lead to a correct diagnosis of iatrogenic FAV, whose surgical correction is usually followed by the restoration of a normal cardiac function.