A rare congenital anomaly of the coronary arteries, in which the left coronary arterial system starts from the arteria pulmonalis, is known as Bland-White-Garland (BWG) syndrome. Isolated left anterior descending (LAD) or circumflex (Cx) arteries originating from the pulmonary artery are even more rare. These anomalies may cause myocardial ischaemia, myocardial infarction, arrhythmia and sudden death. Even if the patient is asymptomatic, he/she should undergo corrective surgery. Here we present the case of an 18-year-old male who survived sudden cardiac arrest during exercise. We identified intra-myocardial blood flow from transthoracic echocardiography, and performed coronary and computed tomographic (CT) angiography, which showed that all the coronary arteries were ectatic and curly and there were disseminated collaterals among the coronary arteries. We diagnosed 'anomalous left coronary artery from the pulmonary artery' (ALCAPA) syndrome, as additionally, the LAD originated from the pulmonary artery. We treated the patient with a left internal mammarian artery - left anterior descending artery (LIMA-LAD) graft.