A patient with severe hypoxia secondary to a large iatrogenic pulmonary artery to pulmonary vein fistula.

Pulmonary arteriovenous malformations are uncommon communications between the pulmonary arteries and veins, most commonly associated with hereditary haemorrhagic telangiectasia. They can also be associated with a variety of other conditions, and can be single or multiple. We present a case of a female patient with a history of coronary artery bypass grafting and mitral valve repair, who presented to the hospital with severe hypoxia. She was found to have a large pulmonary artery to superior pulmonary vein fistula that was successfully repaired using a septal occluder. To our knowledge, this is the first case of a large pulmonary artery to superior pulmonary vein fistula following mitral valve repair.