[Double-chamber right ventricle, aortic subvalvular stenosis and interventricular septal defect. Apropos of 12 cases]. / Ventricule droit à double chambre, sténose sous-valvulaire aortique et communication interventriculaire. A propos de 12 cas.

The authors report 12 cases of double-chamber right ventricle associated with discrete subaortic stenosis and ventricle septal defect. The statistics derived from 3,292 surgical reports of congenital heart diseases operated on at the Marie-Lannelongue Surgical Center over an 8 years period show that this association is 7 times more frequent than the law of chance. Twenty-two per cent of double-chamber right ventricles had an associated discrete subaortic stenosis and, in 9% of cases of subaortic stenosis a double-chamber right ventricle was observed. The cause of this malformation could be a developmental defect of the primitive interampullar ring.

[Origin of the common pulmonary vein, septation of the primary sinus venosus atrial situs and theory of the "sinus man"]. / Origine de la veine pulmonaire commune, cloisonnement du sinus veineux primitif, situs des oreillettes et théorie du "bonhomme sinusal".

Situated at the entry to the heart, the sinus venosus regulates at an early stage the distribution of the veins. Originally symmetrical, it receives on either side an omphalomesenteric vein, a common cardinal vein (duct of Cuvieri, ductus cuvieri) and a common pulmonary vein. This symmetrical pattern disappears with the obliteration of the rough right pulmonary vein and the invagination of the left ductus cuvieri into the sinusal cavity. Thus, the pulmonary venous blood is kept on the left side and the systemic venous blood is transferred to the right side. This is the usual situs solitus arrangement. Situs inversus is the opposite arrangement. In situs ambiguus the original symmetry is preserved. A sufficiently early cauterization of the left wall of the sinus venosus prevents the left ductus cuvieri from invaginating and results in "absence of coronary sinus"; this arrangement, where part of the original symmetry is preserved, is in fact similar to situs ambiguus. The situs of the liver and stomach is thought not to be determined by these organs but imposed to them by the sinus venosus, more precisely by the invagination--or lack of invagination--of a ductus cuvieri. This would explain the concordance between their situs and that of the sinus venosus and atria. It would appear that two errors are frequently made: the common pulmonary vein is said to originate from the left atrium, whereas it originates from the sinus venosus and only belongs to the left atrium when the sinus is incorporated in the atrium; the transverse septation of the sinus is incorporated to a shift to the right of the left sinoatrial fold which separates the sinus from the primitive atrium. This fold is indeed displaced to the right, but it is more distal and corresponds, in fact, to the cephalic border of the left ductus cuvieri, and its shift is produced by the invagination of that duct.

Migration and torsions of the conotruncus in the chick embryo heart: observational evidence and conclusions drawn from experimental intervention.

It seems difficult to escape the conclusion that conotruncal migration and torsions do occur: The amplitude, direction and timing of these movements can be accurately tracked and they can be experimentally arrested. The movements have a significant function: Associated with the partitionings, they regulate the outlet ventricular distribution at two levels, permitting an adjustment between the ampullae and conus (a function of migration) and between the proximal and distal conal segments (via torsions). Their defects result in malalignments--double outlet right ventricle and transposition of the great vessels, respectively. The mechanism of the migration is linked to the differential growth of ampullae; the right ampulla and certain areas of this ampulla appear as dominant during the embryonic period. The conus is carried by the right ampulla and passively undergoes migration. The mechanism of the torsions is not entirely clear. The proximal torsion appears to be linked to a myocardium--jelly dissociation; the distal torsion seems to be linked to an oriented myocardial growth of its wall; the torsion of the truncus is evidently passive, occurring as a consequence of the conus distal torsion.

[Single ventricle and malposition of the dorsal part of the interampullary septum. Experimental study on the chick embryo heart]. / Ventricule unique et malposition de la partie dorsale du septum interampullaire. Etude expérimentale sur le coeur d'embryon de poulet.

After the blood has passed through the atrioventricular orifice or orifices or the atrioventricular canal when present, it is distributed to the ventricular ampullae. This distribution depends on the position of the dorsal component or dorsal horn of the interampullary septum with respect to the atrioventricular canal. The position of dorsal horn seems itself to depend on unequal or differential growth of the basal part of the ventricular ampullae. This has been demonstrated by the results, selectively destroying myocardial tissues by cauterisation: "high" cauterisation of the dorsal side of the right ampulla leads to the formation of a single ventricle of the left type; "high" cauterisation of the left side of the left ampulla leads to the formation of a single ventricle right type. In the first case, the dorsal component remains too far to the right, and, in the second, too far to the left. This differential growth which is exaggerated in these cases, also occurs in normal development. The right ampulla seems to be dominant with respect to the left and is responsible for the normal position of the dorsal horn to the left of the right atrioventricular orifice.

[Coronary arteries and their variations. An embryological explanation]. / Les artères coronaires et leurs variations. Une explication embryologique.

The main coronary arteries originate from three vascular circles: The atrioventricular circle, which forms the right coronary artery and the circumflex branch of the left coronary artery; the interampullary circle, which gives rise to the anterior and posterior descending coronary arteries; and the conotruncal circle, also known as the circle of Vieussens, which communicates with the lumen of the truncus arteriosus by way of the coronary ostia and which also anastomoses with the other two coronary arterial circles, thereby establishing the definitive coronary arterial circulation. A diagram facilitates an easy representation of the numerous variations of the coronary arteries that have been described.

[Myocardium-cardiac jelly dissociation and conal torsion. A study on the chick embryo heart]. / Dissociation myocarde - gelée cardiaque et torsions conales. Etude sur le coeur d'embryon de poulet.

Conal twisting seems to result from dissociation between the cardiac jelly and the deep myocardial interface like the lining in the sleeve of a jacket. The conal ridges are the natural markers of the jelly and endocardium. They are responsible for septation of the conus and enable the twisting to be observed and measured. The myocardium is marked artificially by cauterisation. This marks the armature of the wall and leaves behind a zone of reduced resistance in the form of a hernia or false diverticulum. The conal ridges and marked myocardium dissociate. In the mid segment the myocardium does not play any role in twisting. In the proximal and distal segments it is only partially involved. This dissociation is observed even in the structure of the conal wall; the jelly, which is dense near the endocardium, is loose near the myocardium and adheres to the deep surface by dispersed fibres. Perfusion under pressure of the investigated specimens induces a detachment between the jelly and the myocardium and there only. This fragility only lasts during the twisting period. It is not found at the end of cardiac embryogenesis. This zone would allow not only a sliding--due to its fragility--but also a controlled sliding--by its fibres. In addition to twisting there is also conal migration. This takes place in the same direction as proximal twisting and determines myocardial rotation, which is less marked however, than that of the corresponding ridges. Experimentation may exaggerate this dissociation by preventing migration. It may also reduce or even suppress it by the formation of adhesions between the two layers. Although this mechanism is not univocal, a myocardial-jelly adhesion could stop distal twisting for example and explain malposition or transposition of the great vessels. This dissociation is no unique to superior vertebrates as it has also been found in the first living animals in whom conal twisting occurs, the dipneustes.

Experimental creation of univentricular heart in the chick embryo.

An experimental study on the heart of the chick embryo demonstrates that the atrio-ventricular canal does not migrate towards the right, but that it is the inter-ampullar ring which almost completely migrates to the left. Consequently: 1. absence of migration of the interampullar ring will be responsible for the development of type A univentricular heart with an accessory chamber; 2. incomplete migration will result in a special type in which the right atrioventricular orifice overrides the septum; 3. excessive migration may be the explanation for the development of type B univentricular heart; 4. lacking or incomplete development of the inter-ampullar ring is the cause for the development of type C or D univentricular heart. In most of the cases, the univentricular heat can be considered the result of arrest of the normal embryogenesis at a more or less early state.