Jean Baptiste de Senac was one of the most outstanding physicians in France in the 18th century and made numerous important contributions to cardiology. He had a great interest in anatomy, physiology and pathology of cardiovascular system. De Senac had a great sense of observation and recorded in detail his findings.
His monograph, "Traite de la structure du coeur, de son action, et de ses maladies," is one of the most important medical books of the 18th century. This monumental treatise of 1200 pages was first published in 1749 and contained many original observations. A second revised edition was published in 1783 which was augmented in volume and included new engravings from Antoine Portal, the famous French anatomist. De Senac's text remained influencial for more than a century and was cited by Laennec and Bertin in 19th century.
This first comprehensive cardiology book is divided into four sections and is a systematic analysis of the anatomy including foetal cardiac anatomy , physiology, the circulation of the blood, and cardiac diseases. Most De Senac's observations were based on the great number of autopsies that he performed throughout his life.
In the anatomic section, De Senac provided an accurate account of the organization of myocardial fibers. He described precisely the structure of the cardiac valves including the mitral valve. His description of the mitral subvalvular apparatus was detailed and differentiated the marginal chordae from the chordae attached to the ventricular aspect of the mitral valve leaflets. He also commented on the presence of basal chordae at the level of the posterior leaflet and their absence on the anterior leaflet. He mentioned that the number and the position of chordae present with individual variability and that they became thinner with more divisions as they inserted closer to the free margin of the leaflets.
De Senac also reported that the mitral valve was a stronger structure compared to the tricuspid valve. He explained that the closure of the mitral was "tighter" as mitral valve leaflets have a greater height compared to the tricuspid valve leaflets.
He also reviewed the anatomy of cardiac valves as observed by other major anatomists of his time or those who preceded him. De Senac's anatomic description of cardiac valves is displayed here.
De Senac's treatise is accompanied with a great number of engravings. These fine engraved plates are magnificent and of historical importance due to their precision.
Regarding cardiac pathology, De Senac described cases of pericardial effusion and pericarditis. He mentioned the association between heart failure and hydrothorax. He also suggested a direct relationship between age, and lack of physical activity ("mode de vie sedentaire") and the incidence of heart disease.
De Senac reported several cases of valvular heart disease including a case of mitral valve ossification. He wrote that all cardiac valves could be ossified. He, however, recognized that the semilunar valves were more affected than the atrioventricular valves. De senac made reference to the work of William Cowper who gave the first account of aortic valve ossification with aortic insufficiency in 1706. He also mentioned Vieussens' observation of a case of aortic valve stenosis leading to a severe obstruction of the left ventricular outflow tract. He finally reported his own observation of a case of mitral valve ossification with symptoms of congestive heart failure. He wrote that the leaflets were thickened, ossified and adherent to the ventricular wall at postmortem examination. Similarly, the chordae were heavily thickened and ossified. He finally mentioned that the cardiac chambers were dilated and that the left ventricle was larger than the right ventricle. It is interesting to note that the patient ,described by De Senac, presented with both mitral stenosis and regurgitation and this fact was recognized by him. From clinical point of view, De Senac was among the first physicians to suggest that pulmonary symptoms such as asthma and orthopnea, and lower extremities edema could be from cardiac origin.
De Senac was also the first to discuss mitral regurgitation and to mention that although mitral regurgitation and stenosis were two complete different entities, they had very similar consequences with respect to left atrial dilatation and pulmonary manifestations. De Senac wrote that after the ossification and retraction of mitral leaflets, the blood regurgitates into the left atrium leading to the dilatation of this chamber. Subsequently, the orifice of the mitral valve enlarges and additional blood enters the left venticle which would then cause ventricular dilatation. He concluded that if the mitral valve orifice stays open entirely or partially that would have the same drawbacks as if the mitral orifice was narrowed. In both cases, blood accumulates in the atrial chamber forcing its walls and leading to its distension.
De Senac's text is extremely modern and could have been written by one of our contemporaries. Unfortunately, historians in medicine have not acknowledged the first description of mitral regurgitation by him. The entire text of this discussion on the consequences of mitral stenosis and regurgitation is displayed here.
Finally, De Senac wrote extensively about palpitation. He believed that palpitation could result from cardiac diseases and particularly from mitral valve disease. He reported cases of palpitation in both mitral stenosis and regurgitation. He also speculated that palpitation should be more intense in mitral regurgitation as the blood regurgitates into the left atrium. He postulated that palpitation is caused by the accumulation of blood which irritates the fibers of left atrial wall. Furthermore, he mentioned that long and rebellious palpitation was related to distension and strain of the atria with increased atrial volumes. In his treatise, De Senac also described the irregular pulse of atrial fibrillation as we recognize it today and suggested the use of quinine for the treatment of palpitation.
Degris G. Etude sur Senac, Premier medecin de Louis XV. Thesis for doctorate of medicine. Paris, 1901
Bowman IA. Jean Baptiste de Senac and his treatise on the heart. Texas Heart Inst J 1987;14:4-11
McMicheal J. History of atrial fibrillation 1628-1819, Harvey-de Senac-Laennec. Br Heart J 1982;48:193-197