Caudal vena cava obstruction caused by redundant pacemaker lead in a dog.

Inferior vena cava obstruction, a rare but serious complication of transvenous pacemaker lead placement in humans, has not been reported in dogs. We describe this complication in a dog that developed ascites 8 months after pacemaker implantation. Radiography disclosed a loop of redundant lead within the caudal vena cava (CVC), and angiography demonstrated obstruction to blood flow. Withdrawal of the loop from the CVC did not restore blood flow. Persistent obstruction was suspected secondary to fibrosis resulting from vascular damage caused by the loop of lead. Angioplasty of the CVC obstruction restored blood flow and resolved the dog's clinical signs.