Anatomic types of single or common ventricle in man: morphologic and geometric aspects of sixty necropsied cases

In 60 necropsied cases of single or common ventricle in man, four major unrelated ventricular malformations were found: (1) absence of the right ventricular sinus, in 47 cases (78%), designated type A; (2) absence of the left ventricular sinus, in 3 cases (5%), type B; (3) absence or rudimentary development of the ventricular septum, in 4 cases (7%), type C; and (4) absence of both ventricular sinuses and of the ventricular septum, in 6 cases (10%), type D. Three types of relationship between the great arteries were present: a normal (solitus) interrelationship, in 9 cases (15%), designated type I; d-transposition, the transposed aortic valve lying to the right (dextro, or d), relative to the transposed pulmonary valve, in 25 cases (42%), type II; and l-transposition, the transposed aortic valve lying to the left (levo or l), relative to the transposed pulmonary valve, in 26 cases (43%), type III. In none was the inversus interrelationship, type IV, displayed. Three types of visceral and atrial situs were found: solitus, or normal, in 50 cases (83%); inversus, an exact apparent mirror image of normal, in 2 cases (3%); and heterotaxy, the uncertain visceral and atrial situs associated with asplenia, in 8 cases (13%). The 60 cases were classified segmentally, according to the anatomy of the three cardiac segments: the great arteries, the ventricular sinuses, and the atria. The classic single ventricle with a rudimentary outlet chamber was found morphologically to be a large left ventricle with a right ventricular infundibulum, the sinus of the right ventricle being absent (type A). The myocardium of the right ventricular infundibulum, of the right ventricular sinus, and of the left ventricular sinus was identified by the distinctive gross morphologic characteristics of each. The planes of the atrial and ventricular septa, and the relationships between the great arteries at the semilunar valves, were measured as projections upon the horizontal plane, relative to the anteroposterior line. An approach to cardiac anatomy is presented which is segmental, morphologic and geometric. This approach has angiocardiographic, electrocardiographic and embryologic applications.