Angiographic diagnosis of an anomalous right coronary artery arising from the pulmonary artery.

Abnormal origin of the coronary arteries from the pulmonary artery can occur in four different ways. Either the left or the right coronary artery, both coronary arteries, or an accessory coronary artery may arise from the pulmonary artery. The most frequent of these malformations is the abnormal origin of the left coronary artery. Many publications have dealt with the clinical, physiological, and anatomical picture of this malformation (7). The majority of patients are symptomatic in early life because of marked anoxia of the anterolateral and apical portions of the left ventricle, the result of insufficient intercoronary anastomoses. Some patients, however, may become symptomatic later in life, and in these abundant anastomoses are found between both coronary arteries. From catheterization and angiographic investigations, there is conclusive evidence that the blood flow is directed from the right coronary artery through intercoronary anastomoses into the distal branches of the left coronary artery and fr...