Exercise performance after repair of anomalous origin of the left coronary artery from the pulmonary artery

Eleven patients underwent exercise testing after operative repair of anomalous origin of the left coronary artery from the pulmonary artery. Five patients repaired after 2 years of age comprised a childhood surgery group, and six patients repaired before 2 years of age comprised an infant surgery group. All patients were exercised using either a treadmill or electronically braked bicycle with simultaneous thallium 201 scintigraphy. Oxygen consumption, carbon dioxide production, pulmonary functions, and electrocardiogram were all monitored continuously. Pulmonary reserve was normal in all patients. Based on heart rate reserve, respiratory exchange ratio, and oxygen-consumption response to work load, two patients in the infant surgery group stopped exercise before achieving maximum aerobic capacity. All remaining patients achieved their maximum aerobic capacity. There was no difference in work rate or oxygen consumption during exercise between the infant and childhood surgical group. Four patients (two in each surgical group) had an impaired chronotropic response to exercise. Three of these four patients demonstrated perfusion defects by thallium scintigraphy. Thallium scintigraphy was normal in all remaining patients. Electrocardiographic abnormalities were noted in seven of 11 patients having ventricular arrhythmias or ST segment depression. It is concluded from this study that exercise performance after repair of anomalous origin of the left coronary artery from the pulmonary artery is not affected by the age at which surgery is performed. Exercise is frequently associated with electrocardiographic evidence of abnormal myocardial perfusion despite frequently negative simultaneous 201Tl scintigraphy.