Austin Flint was one of the most outstanding American physicians of the 19th century. He studied at Harvard Medical School and graduated in 1833. His teachers were prominent physicians such as Jacob Bigelow, John Warren and James Jackson.
Austin Flint had a great interest in physical diagnosis of heart diseases and is regarded as an American pioneer in the application of cardiac auscultation with original contributions of major significance. Flint was a productive academic physician and wrote the first comprehensive American textbook in heart disease. His classic monograph, "A practical treatise on the diagnosis, pathology, and treatment of diseases of the heart," was published in 1859. This textbook of 461 pages is divided into ten chapters dealing with enlargement of the heart, lesions affecting the valves and orifices of the heart, congenital malformations of the heart, inflammatory affections of the heart, functional disorder of the heart, and diseases of the aorta. In the chapter on valvular heart disease, Flint described the clinical symptoms, etiology and physical diagnosis of aortic and mitral valve diseases. He placed a great emphasis on auscultation and described in detail cardiac murmurs in patients with mitral stenosis and regurgitation. An excerpt of the chapter on diastolic and systolic murmurs of mitral stenosis and regurgitation respectively is displayed here.
Austin Flint published a classic article under the title, "On cardiac murmurs", in 1862. From historical point of view, this text is probably the most precise and accurate account of cardiac murmurs published in the 19th century. In this work, he analyzed in detail cardiac murmurs in the setting of valvular heart disease. He devoted considerable attention to the negative impact of valvular lesions on myocardial function. In that regard, Flint commented:
"The murmurs, in themselves, give no information respecting the amount of obstruction from contracted orifices, or of regurgitation from valvular insufficiency...But obstruction and regurgitation singly or combined, inevitably lead to enlargement of the heart; hence the latter becomes evidence of the former...The truth is, the evils and danger arising from valvular lesions, for the most part, are not dependent directly on these lesions, but on the enlargement of the heart resulting from the lesions. We may go a step further than this and say that, ordinarily, serious consequences of valvular lesions do not follow until the heart becomes weakened either by dilatation or by degenerative changes of tissue. So long as the enlargement be due mainly to hypertrophy of the muscular walls, the patient is comparatively safe. Hypertrophy is a compensatory provision, the augmented power of the heart's action enabling the organ to carry on the circulation in spite of the disturbance due to obstruction and regurgitation. Happily, in most cases, hypertrophy is the first effect of valvular lesions, and, for a time, it keeps pace with the progress of the latter. Dilatation, which weakens the heart's action, is an effect consecutive to hypertrophy, and as a rule, it is not until the dilatation predominates that distressing and dangerous evils are manifested."
In the same article, Flint described for the first time the presystolic mitral murmur in the setting of aortic regurgitation. This cardiac murmur is eponymously remembered as Austin Flint murmur (Roulement de Flint). In this publication, Flint described two patients who presented with typical signs of aortic regurgitation and stenosis. In both cases, he noted a distinct presystolic murmur at the apex. At postmortem examination, the mitral valves were normal without gross pathology. Austin Flint described this presystolic mitral murmur as follows:
"...The murmur is oftener rough than soft. The roughness is often peculiar. It is a blubbering sound, resembling that produced by throwing the lips or the tongue into vibration with the breath of respiration. I suppose that the murmur is caused, in these cases, by the vibration of the mitral currents, and that the vibration of the lips or tongue by the breath of respiration represents the mechanism of the murmur as well as imitates the character of the sound. At one time , I supposed this blubbering murmur denoted a particular lesion, viz., adhesion of the mitral curtains at their sides, forming that species of mitral contraction knows as the buttonhole slit; but I have found this variety of murmur to occur without that lesion, and, in fact, as will be seen presently, when no mitral lesion whatever exists."
Austin Flint then provided the following mechanism for the occurrence of this presystolic mitral murmur in the presence of aortic regurgitation:
"...Now in cases of considerable aortic insufficiency, the left ventricle is rapidly filled with blood flowing back from the aorta as well as from the auricle, before the auricular contraction takes place. The distension of the ventricle is such that the mitral curtains are brought into coaptation, and when the auricular contraction takes place the mitral direct current passing between the curtains throws them into vibration and gives rise to the characteristic blubbering murmur. The physical condition is in effect analogous to contraction of the mitral orifice from an adhesion of the curtains at their sides, the latter condition, as clinical observation abundantly proves, giving rise to a mitral direct murmur of a similar character. A mitral direct murmur, then, may exist without contraction and without any mitral lesions, provided there be aortic lesions involving considerable aortic regurgitation. This murmur by no means accompanies aortic regurgitant lesions as a rule; we meet with an aortic regurgitant murmur frequently when not accompanied by the mitral direct murmur... The practical conclusion to be drawn from the two cases which have been given is, that a mitral direct murmur in a case presenting an aortic regurgitant murmur and a cardiac enlargement, is not positive proof of the existence of mitral contraction or of any mitral lesion."
The entire text of Flint's historical article is displayed here.
Shaftel N. Austin Flint, Sr. (1812- 1886): Educator of physicians. J Med Educ 1960;35:1122
Smith DC. Austin Flint and auscultation in America. J Hist Med Allied Sci 1978;33:129
Evans AS. Austin Flint and his contributions to medicine. Bull Hist Med 1958;32:224
Ackerknecht EH. Medicine at the Paris Hospital: 1794-1848. Baltimore, Johns Hopkins Press,1967
Fye WB. Profiles in cardiology: Austin Flint, 1812-1886. Clin Cardiol 1989;12:476-477