Three arterial ostia in the base of the pig's heart. Abnormal ductus arteriosus or an additional stem vessel?

A macroscopic description of four hearts showing three arterial ostia in the base of the pig's heart was carried out. Portions of the vascular walls were histologically examined in three hearts. All hearts belong to the Tetralogy of Fallot group. Spitzer's hypothesis concerning the phylogenetic development of the mammalian heart was tested against the observations. The hypothesis could not be verified. The study leads to the conclusion that the ductus arteriosus has its origin in the base of the heart in the four hearts studied.