LAUSR

Truncus arteriosus is a congenital heart disease in which a great artery, that is balanced positioned above a large ventricular septal defect, gives origin to the ascending aorta, the pulmonary arteries and the coronary circulation. The atrioventricular septum, both ventricles and the left ventricular outflow tract are usually normal. In most cases the common trunk gives rise to the main pulmonary artery which then bifurcates into branch pulmonary arteries generally of normal size. Truncal valve is usually dysplastic with thickened and deformed leaflets and in order from highest to lowest frequency it may be trileaflet, quadricuspid or bicuspid. The absence of one pulmonary artery is rare (1).