Background: Anomalous origin of the left coronary artery (LCA) from the pulmonary artery (ALCAPA) is a rather rare congenital anomaly that has a profound effect on heart function. This study aimed to retrospectively illustrate the perioperative clinical features, therapy experience, and midterm outcomes after surgical correction, and to determine the value of left ventricular ejection fraction (LVEF) and myocardial viability in differentiating critically ill patients among infants and children with ALCAPA. Methods: From April 1999 to March 2013, infants and children patients diagnosed with ALCAPA in Beijing Fuwai Hospital were analyzed. Clinical data of patients were summarized and retrospectively analyzed. All patients were divided into two groups according to LVEF level (Group 1: LVEF >50%, or Group 2: LVEF ≤50%) to compare perioperative and follow-up variables. Effect of myocardial viability evaluated according to myocardial perfusion/18F-fluorodeoxyglucose (FDG) imaging on the clinical variables was also analyzed. Results: A total of 50 patients with ALCAPA (male/female: 29/21; median age: 3.1 years [range: 4 months to 18 years]) were included. Younger age, lower weight, intercoronary collaterals (ICC) dysplasia, ratio of the proximal right coronary artery diameter to the aortic root diameter <0.2, and larger cardiothoracic ratio (CTR) were more frequently found in Group 2 than those in Group 1. Forty-seven patients underwent cardiac surgery. The times of cross-clamp and cardiopulmonary bypass were not different between the two groups; however, the duration of mechanical ventilation and postoperative Intensive Care Unit stay were longer in Group 2 than those in Group 1. Follow-ups were possible in 38 patients (80.9%); median time: 84.5 months (range: 49 months to 216 months). There was one late sudden death with simple ligation of the LCA at 8 months after surgery. No severe complications and reoperation occurred. The relationship of the grades of myocardial viability and clinical features was analyzed in 15 patients with myocardial perfusion/18F-FDG imaging, and the results showed that myocardial viability correlated well with LVEF, CTR, abnormal Q waves, and left ventricular end-diastolic dimension. It was not correlated with age, mitral regurgitation, and ICC. Heart implantation was decided in one patient with little viable myocardium; however, this patient died 2 months after the diagnosis while waiting for transplantation. Two patients with no viable myocardium in the area of aneurysm had aneurysmectomy concomitantly. Conclusions: In infants and children withALCAPA, heart function and myocardial viability are closely related to clinical features. LVEF and the grades of myocardial viability can differentiate high-risk patients before surgery and in the early stage of recovery after surgery. The area and extent of myocardial infarction are also crucial in making preoperative clinical decisions. However, even in patients with depressed ventricular function and severe myocardial infarction, the midterm follow-up showed satisfactory recovery of cardiac function after the successful restoration of a dual-coronary arterial system.