Apical systolic murmur was an entity already recognized at the end of the 19th century, but its significance was not identified yet.
In 1892, Griffith suggested that midsystolic and late systolic murmurs might result from mitral regurgitation. Similarly, in 1903, Hall postulated that late systolic murmurs were from mitral origin. In 1913, Gallavardin reported that apical systolic murmurs were from extracardiac origin and resulted from pleuropericardial adhesions. Great British cardiologists such as Lewis and Mackenzie were of the opinion that apical systolic murmur could be neglected when not accompanied by other signs of heart disease.
Furthermore according to the teaching of Mackenzie and Lewis, isolated mitral regurgitation with no signs of myocardial failure was of little consequence. The following is a statement from Sir James Mackenzie in the third edition of "Diseases of the heart" :
"The really serious trouble in connexion with mitral regurgitation arises when the muscle is impaired and the regurgitation is due to a complication of the dilated orifice and diseased valve. The subsequent results depend on the degree of the exhaustion of the muscle of the heart. The backward pressure resulting from the regurgitation embarrasses the left auricle. The exhaustion also affects the right ventricle and so adds to the embarrassment of the pulmonary circulation. While back-pressure is a factor of importance and may be a predisposing cause, yet it produces comparatively few symptoms until the tonicity gives away, which is manifested by dilatation of the heart...In fact, in the majority of cases, as Graham Steell says, "the change in the valves is altogether inadequate to explain the evidently free regurgitation that occurred during life, and the disastrous dilatation of the heart. The muscle-failure factor, it may be presumed, was the essential one"...It will thus be seen that the symptoms produced by mitral incompetence are only of gravity when there is also muscle failure."
In 1937, Paul white suggested that the mid-systolic murmurs might be from mitral origin due to abnormal chordae tendinae. This concept was not, however, broadly acknowledged by the cardiology community and pleuropericardial diseases remained the main explanation for apical systolic murmur . In 1930's and 40's, two observational studies were published in which the clinico-pathological correlations demonstrated for the first time that the apical systolic murmur was due to mitral regurgitation resulting from either chordal rupture or elongation. Subsequently, in 1960's, significant advances occurred in our knowledge of apical systolic murmur and the recognition of degenerative mitral valve disease with the work of Reid and outstanding contribution of Barlow.
In 1934, Frothingham and Hass reported the first case of mitral valve regurgitation with chordae rupture in the absence of endocarditis at postmortem examination.
The patient was a 65 year old male with chief complain of dyspnea on exertion. Two years prior to this presentation, he had a medical examination at the age of 63 which was unremarkable. At Physical examination, Frothingham noted:
"He was cyanotic and markedly dyspneic. He had pulmonary edema and tachycardia...The heart appeared somewhat enlarged to percussion. No thrills were felt. The first sound all over the precordia was replaced by a harsh systolic murmur."
The patient initially improved with medical therapy. His clinical situation, however, worsened gradually over a period of six months and he died from congestive heart failure.
The autopsy findings were reported as follows:
"The mitral valve and its annulus fibrosus, chordae tendineae and papillary muscles were the seat of the only significant pathological changes in the heart. The orifice easily admitted the passage of two fingers. When viewed from the auricular side, it was noted that the middle three-fifth of the posterior cusp bulged upward into the mitral opening...the middle one-third of the posterior cusp was almost entirely free from its attachments to the papillary muscles. Four ruptured chordae tendineae were found...there was no evidence of either a healed or active endocarditis...in the annulus fibrosus there were irregular masses of calcium which extended for from 1 to 3 mm. into the substance of the valve at its attachment. Of greatest significance was the restriction of these calcific deposits to the annulus fibrosus of the posterior cusp, especially at the attachment of that portion of the leaflet which was affected by the rupture of the chordae tendineae."
Histologic examination of the chordae were described as :
"The tissue was composed of dense as well as loose-textured avascular collagen in which stellate and fusiform connective tissue cells were imbedded...the histology of the intact chordae, which were cut in serial sections for the purpose of making control studies, differed from that of the ruptured chordae tendineae in that the collagen fibrils were arranged in normal, compact, straight, parallel bundles which were of uniform texture."
This is most likely the first description of a case of mitral regurgitation with chordae rupture in the absence of endocarditis. Although the authors ruled out the latter etiology, they did not elaborate any hypothesis regarding the potential cause of mitral valve disease in their report. Frothingham and Hass obviously did not understand the significance of their findings at that time.
Considering our current knowledge, several elements in this report direct us toward the diagnosis of degenerative mitral valve disease and more specifically fibroelastic deficiency which was first described by Alain Carpentier in 1975.
In fact, the age of the patient at presentation (greater than 60), the short period of evolution of the disease and the absence of a history of systolic murmur are all characteristic features of fibroelastic deficiency. Similarly the gross macroscopic view of the valve (see above), description of valvular lesions such as moderate annular dilatation, prolapse of the middle scallop of the posterior leaflet due to chordae rupture, and mild annular calcification, and finally histological findings are altogether in favor of this affection.
Griffith JPC. Midsystolic and late systolic mitral murmurs. Am J Med Sci 1892;104:285-94
Hall JN. Late systolic mitral murmurs. Am J Med Sci 1903;125:663-66
Gallavardin L. Pseudo dedoublement du deuxieme bruit du coeur simulant le dedoublement mitral par bruit extra-cardiaque telesystolique surajoute. Lyon Med 1913;121: 409-77
White PD. Congenital cardiovascular defects. Heart disease, 2nd Ed. New York, Mackmillan, 1937