Perloff's Clinical Recognition of Congenital Heart Disease (Seventh Edition) - Chapter 25: Truncus arteriosus

Truncus arteriosus is characterized by a failure of the aorta and pulmonary artery to separate into two distinct structures with their own semilunar valves. Therefore, truncus arteriosus is characterized by a single great artery with a single semilunar valve that leaves the base of the heart and gives rise to the coronary, pulmonary, and systemic circulations. The single arterial trunk received the output of both ventricles and so a ventricular septal defect is obligatory and the truncus is dilated.