persistent truncus arteriosus persistent trun·cus ar·te·ri·o·sus (trŭng'kəs är-tēr'ē-ō'səs)
n.
A congenital cardiovascular deformity resulting from the failure of the septum between the aorta and pulmonary trunk to develop and characterized by a common arterial trunk opening out of both ventricles with the pulmonary arteries branching from the ascending common trunk.