a direct communication between an artery and vein, without an intervening capillary bed. It can occur as a congenital abnormality or it may be acquired following injury or surgery. It may affect the limbs, lungs, or viscera and may be single or multiple. If the connection is large, the short-circuiting of blood may produce heart failure. Large isolated arteriovenous aneurysms may be closed surgically.
* * *
a communication, either congenital or traumatic, between an artery and a vein; arterial blood may flow directly into the vein (aneurysmal varix) or be carried into it by a connecting sac (varicose aneurysm).Medical dictionary. 2011.