The direction of blood flow in anomalous left coronary artery arising from the pulmonary artery.

MYOCARDIALI infaretion in infancy secondary to the anomalous origin of the left coronary artery from the pulmonary artery is now a condition that is being recognized with increasing frequency during life. One of the more interesting aspects of this congenital abnormality is the problem of the direction of the blood flow in the left coronary artery. In 1886 St. John Brooks1 first postulated that the flow in an anomalous coronary artery was retrograde. Following an anatomic dissection in 2 cases in which the right coronary artery arose from the pulmonary artery, he concluded that arterial blood flowed from the normal left coroinary artery, which arose from the aorta, through anastomotic collateral vessels into the right coronary artery with ultimate drainage into the puLlmonary artery. If the flow is retrograde, it is apparent that one of the coronary arteries is not only failing to supply the myocardium but is actually draining fully oxygenated blood from the heart into the pulmonary artery. Recentlv Edwards2 and others have presented further evidence in support of this view. The present communication concerns a patient with anomalous origin of the left coronary artery from the pulmonary artery in whom the direction of blood flow in this vessel was studied and demonstrated conclusively.