A patient who had high-output heart failure resulting from anastomosis of the intercostal and bronchial arteries to the right pulmonary artery is reported. The patient was a fifty-one year-old man who was admitted to our hospital with left heart failure. A radionuclide angiocardiogram revealed blood flow from the aorta to the right pulmonary artery. A descending aortogram revealed abnormally dilated right intercostal and bronchial arteries, which formed the anastomosis. The right pulmonary artery was visualized via that anastomosis. Tuberculous pleurisy in the patient's history was considered to be the cause of the anastomosis. The therapeutic procedure used was embolization via a catheter for the anastomosis, but most anastomoses could not be embolized. The present report is considered the first on anastomosis of the intercostal artery to the pulmonary artery to the extent that high-output heart failure occurs.