Aortopulmonary Window is a rare congenital heart defect comprising 0.1-0.2% of the total spectrum. Spontaneous closure of this defect is unknown and survival into childhood and adult life is rarely seen. Severe pulmonary artery hypertension develops and causes dilatation of the pulmonary artery. Left main coronary artery extrinsic compression by an enlarged pulmonary artery is a rare complication and a potential cause for chest pain and sudden cardiac death in patients with pulmonary hypertension.