Left-ventricular function and myocardial perfusion were studied in 8 patients for between 3 and 21 years (mean 16 years) after ligation of the anomalous left coronary artery from the pulmonary artery. While only one patient complained of exercise-dependent stenocardia, 4 patients had abnormal ST-segments in the exercise ECG and all patients showed myocardial ischemia at exercise scintigraphy. At rest, the ejection fraction of the left ventricle was within normal range in all patients. In 5 patients, it failed to increase adequately under exercise conditions, reflecting impaired ventricular function. These results confirm the advantages of surgical procedures establishing a 2-coronary system.