Most pulmonary arteriovenous fistulas occur in one lobe or segment of the lung, and the abnormal artery and vein, the ones causing the fistula, can be identified through minimally invasive thoracoscopy and the lesion surgically removed. Usually only the diseased segment of the lung is removed and no lobectomy is required. If the arterial and venous fistula is removed, there is no short circuit from the artery to the vein and cardiac function can be improved and the congenital pulmonary arteriovenous fistula can be cured. If a severe pulmonary arteriovenous fistula exists throughout the lobe, it may cause cardiac effects, such as right heart failure.