The conducting system of the heart in the syndrome of visceral symmetry
Pohanka, I.; Vítek, B.
Folia Morphologica 26(4): 379-388
1978
ISSN/ISBN: 0015-5640 PMID: 711046 Document Number: 133690
The conducting system of the heart of 2 deceased infants with the syndrome of visceral symmetry was examined by serial histological sections. In the 1st case there were bilateral bilobed lungs, polysplenia, isomerism of the heart atria with a symmetric inlet of 2 superior venae cavae and a common ventricle, D-transposition of the great arteries and atresia of the pulmonary artery. In the 2nd case there were bilateral trilobed lungs, asplenia, isomerism of the heart atria with a symmetric inlet of 2 superior venae cavae and a common ventricle with a small outlet chamber, a double outlet of a small outlet chamber and L-transposition of the great arteries with infundibular stenosis of the pulmonary artery. In both cases isomerism of the sa[sino-atrial]-node was found, the left one of which was the pacemaker of the heart. Two av[atrio-ventricular]-nodes were also formed, one in the place of the anterior endocardial cushion and the other in the place of the posterior endocardial cushion. These 2 cases are characteristic models of the early stage of the embryonic development of the heart. The mode of development of the conducting system is discussed.