Origin of the left coronary artery from the pulmonary artery.

A 45-year-old woman with angina pectoris, beginning at the age of 16 and progressing to produce incapacitation, was found to have an anomalous left coronary artery arising from the pulmonary artery. Because of the severity of symptoms and progression' of disability, the anomalous artery was ligated at its origin from the pulmonary artery. Pressure in the left coronary system increased from 35/10 to 105/30 mm Hg. Since operation the patient has been relieved of her symptoms. There was no evidence of increased myocardial ischemia after ligation. This indicates that operative treatment of this anomaly can be carried out successfully in the older age group. It is also suggested that a fourth stage of progression of this anomaly occurs in which there is an exaggeration of the intercoronary communications between the right and left coronary systems. This produces such a large arteriovenous shunt that blood flow to the myocardium is again reduced, resulting in a "coronary steal syndrome."