Aortic dextroposition complexes in the fowl: A study in comparative pathology

Abstract

CONGENITAL anatomical defects in the human heart and its associated great vessels have, naturally, been the subject of much study. Similar defects occur in other mammals, but many records of this aspect of comparative cardiology are located in obscure journals. In the last decade, however, with the increasing interest in comparative medicine, certain specific cardiac malformations in domestic mammals (van Nie, 1961; Detweiler, 1962; Patterson, 1963; Fisher and Pirie, 19643) as well as in birds (Siller, 1958) have been the subject of extensive study. It is noteworthy that the heart defects found in birds, where the embryo develops in the independent closed system of the egg, appear to be homologous with malformations in the mammal, where the foetus develops in a very Werent and maternally dependent environment.Reports of spontaneous cardiac malformations in birds are rare and most refer to duplication of the heart. The earliest reference known to the author on dupZicitaS cordis in birds is the statement attributed to Theophrastus , that in Paphlagonia partridges have two hearts. This seems to have been common belief in those days since both Pliny in his Natural history and Gellius in his Attic nights make mention of it. Though it would not be difficult to guess the explanation of this belief, its true origin is lost in obscurity.Littre (1709) reported on two cases of cardiac duplication in fowls and D'Aboville (1786) was so astounded by his discovery of two hearts in a partridge that he obtained affidavits on the veracity of his observation from two friends.Similar observations on birds with two hearts were made subsequently by Meckel (1815), Panum (1859), Constantinescu (1900) and Stanski (1951). However, Larcher (1874) believed that the duplication of hearts in birds is not genuine, but due to exaggerated fissure of the normal heart. He refers to a specimen of a fowl heart in the Museum for Comparative Anatomy at Bologna where the two sides of the heart are completely separated one from the other so that each side has a ventricle and an atrium. Four normal hearts have been reported in one fowl (Mostafa, 1952) and there is the famous case of Verocay (1905) who saw seven apparently normal hearts in one chicken.Descriptions have been given of an ectopic heart in a wild teal (Waterston, 1905-06), one in a pigeon (Joest, 1913) and one in a parakeet (Tuttle and Greene. 1957). Reinhardt (1925, cited by Reis and Nobrega) and Gylstofl (1961) each record a case of patent foramen ovale in a fowl. The morphology of ventricular J. PATH. BACT.-VOL. 94 (1967) 155 156 W. G. S I U E R septal defects in fowls has been described in detail by Siller and their embryological development by Rychter, LemeZ and Siller (1W). FOWL HEART DEFECTS 157 PLATE LIX FIG . 12 (case 19).-Cor triloculare biatrium. View from below and to left of the 1 of the left side of the common ventricle. Under the glass rod is the very large cuspid left AV valve. Below and to the left of it is the stenotic bicuspid right valve, which has becn incised. X...