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• v.12(4); Oct-Dec 2011

Classics in Cardiology: On Cardiac Murmurs (Part 1) *

Austin flint.

Professor of the Principles and Practice of Medicine in the Bettevue, Medical College, N. Y., and in the Long Island College Hospital

The clinical study of cardiac murmurs, within the last few years, has led to our present knowledge of the diagnosis of valvular lesions of the heart. By means of the organic murmurs, it is positively ascertained that lesions exist in cases in which, without taking cognizance of the murmurs, the existence of lesions could only be guessed at. The absence of the organic murmurs, on the other hand, enables us generally to conclude, with positiveness, that valvular lesions do not exist. As a rule, to which there are but a few exceptions, these lesions may be excluded, if there be no murmur. These are great results; but the practical auscultator of the present day need not be told that the clinical study of cardiac murmurs has led still further into the mysteries of diagnosis. Having ascertained the different murmurs which occur in connection with valvular lesions, having traced their connection, respectively, with different lesions, having shown their relations to the movements of several portions of the heart and to the cardiac sounds, and having explained satisfactorily the mechanism of their production, we are able to determine not only the existence or non-existence of valvular lesions, but also their particular situation when they are present, and to a certain extent, their character and consequences.

The practiced auscultator, by listening to the murmurs alone, is able to tell whether lesions are situated at the mitral, or the aortic, or the pulmonic orifice, and he is able to say, in certain cases, that the valves which are to protect these orifices against a regurgitant current of blood have been rendered by disease inadequate to their office. It is unnecessary to adduce proof of these statements; their correctness is sufficiently known to those who are conversant with physical exploration as applied to the diagnosis of affections of the heart. How strikingly do these facts exemplify the progress of practical medicine to those who, although still among the junior members of the profession, have practiced before and since the recent developments in this department of our knowledge!

These remarks are introductory to the consideration of various practical points pertaining to the cardiac murmurs. And the first subject will relate to these murmurs in general, viz., the limitations of their significance . After having considered certain points embraced in this subject, I propose to take up various points relating to the different murmurs separately.

By the limitations of the significance of the murmurs, I mean the actual amount of knowledge respecting valvular lesions to be derived from this source. It is evident, from what has been stated already, that the knowledge which they convey is of very great importance, but important as this knowledge is, it has certain limits which are not always sufficiently understood, and as a consequence, the practitioner is liable to fall into unfortunate errors of opinion as regards the gravity of the lesions which the murmurs represent.

Prior to the clinical study of the cardiac murmurs, the existence of organic affections of the heart was recognized when, in conjunction with disturbed action of the organ, symptomatic events had taken place which belong to an advanced stage of only a certain proportion of cases. Dyspnea, palpitation, and dropsy were the symptoms mainly relied upon for the diagnosis. The recognized cases were then comparatively rare, and when recognized, a speedily fatal issue was expected. This fact, together with the frequency with which cardiac lesions were revealed by postmortem examinations in cases of sudden death, rendered the diagnosis of organic disease of the heart equivalent to a summons from the grave. The prognosis, as a matter of course, was as unfavorable as possible; the doom of the patient was either to die unexpectedly at any moment or to endure protracted sufferings until released by death. The study of the murmurs together with the application of other signs enabled the practitioner to recognize organic affections at a period in the disease when otherwise they would not have been discovered. The recognized cases became more frequent. Persons who presented few or no symptoms pointing obviously to disease of the heart were found to have cardiac lesions. The ideas which had prevailed relative to the gravity of organic affections, however, naturally enough, continued to prevail. An organic murmur, consequently, had a fearful significance. It was considered as proof of disease which was not less surely destructive because earlier ascertained. Let it be said of a patient that he had a cardiac murmur denoting a valvular lesion, and his doom was pronounced; sudden death, which might occur at any time, or an early development of the distressing symptoms characteristic of cardiac disease, were to be expected, whatever might be his present condition.

So far from concealing from patients the fearful significance of cardiac murmurs, it was considered important for them to understand fully their precarious condition, in order to receive their cooperation in the measures of management which were deemed essential. These measures embraced general and local blood-letting, depletion by cathartics, sedative remedies addressed to the circulation, mercurialization, low diet, together with as much inaction of mind and body as possible. The consequences of this management were calamitous in the extreme. In fact, these measures contributed, in small degree, to the fulfillment of the gloomy predictions impressed upon the minds of the unfortunate patients who were found to present the auscultatory sign of valvular lesions. So long as these notions with regard to the treatment of cardiac affections prevailed, an early diagnosis, instead of being desirable, was a serious disadvantage, and truly fortunate were they who kept aloof from the stethoscope of the auscultator!

Erroneous views respecting the significance of cardiac murmurs, and also respecting the indications for treatment in cases of organic disease of the heart, are still, to a greater or lesser extent, prevalent. I propose now to confine myself to the former, i.e., the significance of the murmurs. It is obvious that with the acquirement of means of ascertaining the existence of lesions at an early period, when, without these means, the lesions could not have been discovered, clinical experience had to take a new point of departure as regards prognosis. And experience has shown that lesions giving rise to cardiac murmurs by no means invariably denote impending danger or serious evils, and that they are not infrequently innocuous. Several clinical observers, within the last few years, have contributed facts going to show the correctness of this statement. Of these, Dr. Stokes is especially prominent. Dr. Gairdner, of Edinburgh, has lately communicated a valuable paper on this subject. I have been able to gather some facts having an important bearing on the subject under consideration. Of the cases which have come under my observation, exemplifying the “limitations of the significance of cardiac murmurs,” I shall select a few of the most striking.

Thirteen years ago, I attended a child, aged 11 years, with a slight rheumatic attack. Directing attention to the heart, I found a very loud mitral, regurgitant murmur, heard over the left lateral surface of the chest and on the back. The heart was enlarged; the extent and degree of dullness in the praecordia being increased, and the apex beat without the nipple. The murmur was evidently not due to an endocarditis developed during the present attack of rheumatism; the lesion giving rise to it probably originated in an obscure thoracic affection which had occurred 7 years before. I was at that time less acquainted with the significance of cardiac murmurs than now, and I deemed it my duty to inform the mother of the patient of the existence of an organic affection of the heart, which would be likely to destroy life within a period not very remote. The patient is still living. She is now 24 years of age, and although presenting a delicate appearance, a casual observer would not suspect the existence of any disease. She is subject to palpitation, to coldness of the extremities, and experiences want of breath on active exercise, but she does not consider herself an invalid, and the apprehensions caused by my communication to the mother have long since disappeared.

It is fair to presume that my opinion in this case was considered as a mistake. It was, indeed, an error of judgment as regards the prognosis, but the diagnosis was correct; the loud bellows murmur is still there, and heard over the whole chest, even through the dress, and the heart is considerably enlarged. The patient, if not destroyed by some intercurrent affection, will ultimately die of cardiac disease; yet, it is now 20 years since the probable commencement of the lesions giving rise to the cardiac murmur.

Nearly 20 years ago, a person was examined by a medical friend with reference to an assurance on his life. My friend, finding a loud murmur and an abnormally strong action of the heart, brought the person to me as an interesting case for examination. I failed to record the case, and am not therefore positive as regards the particular murmur present, but I think it was the mitral regurgitant. Since that examination, until recently, I have been in the habit of meeting this person often, although he has never been my patient. He has been, and still is engaged in active business. He is now about 50 years of age. He has survived his wife, and been again married within a few years.

I have selected these two cases as illustrating the duration of life and comfortable health for 13 and 20 years after a loud organic murmur, together with enlargement of the heart, had been ascertained; in both cases, life and comfortable health are continuing at the present moment. I could cite, in addition, numerous cases of persons now living, and apparently well, who have had organic murmurs for several years. In making examinations of chests, supposed to be healthy, for purposes of study, I have repeatedly found a murmur, evidently organic, when no disease of the heart was suspected either before or after my examination. The following case is instructive, as showing the importance of taking into account the coexistence of functional disorder of the heart, dependent on anemia, with organic disease.

In November 1852, I visited, in consultation with Professor Rogers of Louisville, a lady aged about 25. She had had repeated attacks of acute rheumatism. She had an infant several months old, which she was nursing, and she had become quite anemic. She had begun to suffer from palpitation during the preceding summer, and her attention was attracted to a sound in the chest which she heard in the nighttime. This sound was also heard by a sister with whom she slept. She described, of her own accord, the sound to be like that produced by a pair of bellows. She had never heard of cardiac bellows-murmurs, and at this time there had been no examination of the chest. Prof. Rogers had been called to the patient a short time before my visit, and detected at once the existence of organic disease.

She presented an aortic direct and a mitral regurgitant murmur, both loud; the heart was moderately enlarged, and its action violent. She was conscious of this violent action, and slight exercise or mental excitement occasioned much distress from palpitation. The urgent symptoms in the case were attributed to anemia; weaning was at once enjoined, and chalybeate remedies, etc., were advised. I met the patient a year later without recognizing her. She was apparently in perfect health and presented a blooming appearance. Her friends thought we must have been mistaken in our opinion as to the existence of organic disease of the heart. The murmurs and the signs of enlargement, however, were still there. She continued to enjoy good health until the summer of 1856, when she suffered from uterine hemorrhage and again became anemic. The action of the heart became irregular, and she complained much of vertigo. Tonics, stimulants, nutritious diet and fresh air failed to remove the anemic state, and at length she was seized with apoplexy and hemiplegia. She recovered from the apoplexy, but the hemiplegia continued, and death took place between 2 and 3 weeks after the apoplectic seizure.

The significance of organic murmurs is limited to the points of information already stated in the introductory remarks, viz., the existence of lesions, their localization, and the fact of valvular insufficiency or regurgitation. Whether the lesions involve immediate danger to life, or, on the contrary, are compatible with many years of comfortable health, the murmurs do not inform us, nor do they teach us how far existing symptoms are referable to the lesions, and how far to functional disorder induced by other morbid conditions. Neither the intensity nor the quality of sound in the murmurs furnishes any criteria by which the gravity of the lesions or their innocuousness can be determined. A loud murmur is even more likely to be produced in connection with comparatively unimportant lesions than with those of a grave character because in the former, rather than in the latter case, is the action of the heart likely to be strong, and the intensity of the murmur, other things being equal, will depend on the force with which the currents of blood are moved. Whether the murmur is soft, or rough, or musical, depends not on the amount of damage which the lesions have occasioned, but on physical circumstances alike consistent with trivial and grave affections.

It may be imagined that these assertions, although true as regards murmurs produced by the direct currents of blood, do not hold good with respect to the regurgitant murmurs. The latter, it may be said, involving as they do insufficiency of the valves, will be loud in proportion to the amount of blood which regurgitates, and, therefore, the intensity of the murmur should be a criterion of the amount of valvular insufficiency. But clinical observation disproves this surmise. A minute regurgitant stream is as likely to be intensely murmuring as a large current, perhaps even more so. Here, too, the loudness of the sound will depend, in a great measure, on the power of the heart's action. To this point I shall recur when I come to consider the different murmurs separately.

The practical injunction to be enforced in connection with the limitations of the significance of the cardiac murmurs is that we are not to judge of the magnitude of valvular lesions, of the amount of danger on the one hand, or of the absence of danger on the other hand, by the characters belonging to the murmurs. The physician who undertakes to interrogate the heart by auscultation is not to decide that the condition of his patient is alarming, simply because he finds a murmur which he satisfies himself is dependent on an organic lesion of some kind. The lesion may be at that time, and perhaps ever afterward, innocuous; the evils arising from cardiac affections may be remote, and so far from plunging the patient into despair by the announcement of the fact that he has an incurable disease of the heart, there may be just grounds for holding out expectations of life and comfortable health for an indefinite period. Neither does it necessarily alter the case when more than one murmur is discovered; the existence of several murmurs by no means excludes the possibility of similar encouragement. We are to look to other sources of information than the murmurs in forming an opinion respecting the gravity of the affection. What are the sources of information on which our opinion is based? It does not fall within the scope of this essay to consider at length the points involved in the answer to this inquiry. I shall answer it in a few words.

The heart sounds furnish means of determining whether the lesions are of a nature to affect materially the function of the valves. I must here pass by this useful and beautiful application of auscultation with a simple allusion to it, referring the reader elsewhere for a full exposition of the subject. I shall, however, return to the subject presently in considering the murmurs individually. Means requiring less proficiency in physical exploration relate to enlargement of the heart. It is not a difficult problem to determine whether the heart be or be not enlarged, and it is easy to determine the degree of enlargement. Now, in general, if valvular lesions have not led to enlargement of the heart, they are not immediately dangerous, and the danger is more or less remote. Here is a criterion of great importance in estimating the gravity, on the one hand, or the present innocuousness, on the other hand, of lesions giving rise to murmurs. So long as the heart is not enlarged, the lesions cannot have occasioned to much extent those disturbances which arise from contraction or patency of the orifices. The murmurs, in themselves, give no information with respect to the amount of obstruction from contracted orifices or of regurgitation from valvular insufficiency. Let this fact be constantly borne in mind. But obstruction and regurgitation, singly or combined, inevitably lead to enlargement of the heart; hence, the latter becomes evidence of the former. The degree of enlargement is, in general, a guide to the extent and duration of the disturbances occasioned by contracted and patescent orifices. As a rule, if the heart be slightly or moderately enlarged, the immediate danger from the lesions which may give rise to one or more loud murmurs is not great.

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 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 is 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.

The practical bearing of these views respecting hypertrophy and dilatation, on the management of organic affections of the heart, is obvious. They are inconsistent with the employment of measures to prevent or diminish hypertrophy; on the contrary, they point to the importance of an opposite end of management, viz., to encourage hypertrophy in preference to dilatation and to maintain the vigor of the heart's action. It does not fall within the scope of this essay to consider therapeutic applications, and I must content myself with this passing notice of an immensely important reform in the management of organic affections.

Returning to the means of determining the gravity of valvular lesions, I repeat, they become serious, in other words, the distressing and dangerous symptomatic events are to be expected, in proportion as hypertrophy merges into dilatation, or as weakness of the organ may be induced by structural degeneration or other causes. In connection, then, with murmurs, we are to determine the condition of the heart as respects the points just mentioned, in order to estimate properly the gravity of the lesions which the murmurs represent. In leaving this subject, viz., the limited significance of the cardiac murmurs, I will give a case which is a type of a class of cases not infrequently coming under observation. In the spring of 1860, I was consulted by a medical gentleman from a distant state, who furnished me with the following written statement of his case:

“About a year ago I went to the city of _________ to place myself under the care of Dr. _________, for a trifling surgical difficulty with which I had been annoyed for a long time. At long intervals previous to that time, I had had severe pains in the left breast about the cardiac region, but at no time from any constant pain. I thought the pain was of a neuralgic character. While at _________ 1 thought I would have my lungs examined, as some members of my family had been consumptive. I went to Dr. _________ and to Dr. _________, both of whom pronounced my lungs sound, but said that my heart was affected. I came home much depressed by their opinion, and suffered so much from mental anxiety that in the course of a month or two I determined to go back and consult another medical gentleman, Dr. _________. He told me there was some roughness about the sounds of the heart but no serious organic disease. I was much relieved by this opinion, and clung to the belief that the pains were of a neuralgic character.

Previous to my going to _________ I had all my life taken a good deal of out-door exercise, such as riding, hunting, fishing, etc., for the purpose of warding off any tendency to consumption. I have always had a frail figure and been inclined to despondency. I have suffered a great deal of anxiety, owing to family affairs and business matters. After my return from consulting Dr. _________ I thought it best to give up active exercise for fear of increasing any cardiac affection that might exist. I do not think that I have had any severe pain in my chest frequently, at any time, but only at intervals and apparently occasioned by anxiety about patients, etc.

In December last I went into the country, 13 miles to see a patient. The weather was very cold, rainy, and windy; I returned in the night. I was suffering from toothache and smoked a cigar in order to relieve the pain. I went over to my office to write a prescription for a sick child, and on my way back I was attacked by palpitation of the heart for the first time in my life. I came into the house and lay down, when I was seized with severe rigors without chills. I had also pain in the back, and afterwards fever. Since then I have been subject, at intervals, to a jarring or knocking sensation about the heart, but no palpitation of long continuance. I cannot sleep as well on my left side as formerly, as it causes an uneasy sensation with something like palpitation and some pain. I do not take much exercise, and find that I get out of breath easily. I am very sensitive to cold. The attacks of increased action of the heart are always accompanied by rigors and irritability of the bladder.

On the 19 th of March, I was taken with a feeling of fatigue and indigestion, followed by severe rigors together with great heat of the head and body. The circulation was rapid and accompanied by palpitation. The attack lasted nearly an hour, and I feel the effect of it today, March 22. I notice, when reading a newspaper or small book that the action of the heart causes it to vibrate. During my first attack in Dec., I had an intermittent pulse. I did not recover from that attack so as to go out for a week, and have not since been as well as before.

Fearing that my situation was critical I have been careful of myself. I have feared to increase the affection and that I might die suddenly. But I have had fear that in taking care of the cardiac affection I shall increase a tendency to consumption. Any mental anxiety increases the action of the heart. I do not smoke nor chew tobacco, nor drink any alcoholic liquors. I have suffered much from toothache; in other respects have had generally very good health. I have never had rheumatism. I am a married man with five children. I think my cardiac affection has been getting worse since December last, and I suffer in mind dreadfully on that account, as I have a great deal to live for.”

On examination of the chest, in this case, I found the apex beat in the 5 th intercostal space half an inch within a vertical line passing through the nipple. The area of superficial cardiac dullness carefully delineated on the chest, was found to be of normal extent. The left border of the heart fell within the nipple. The respiratory murmur, on a deep inspiration, was heard over the whole praecordia. The apex beat was not abnormally strong; no other impulse was discovered, and no heaving of the praecordia.

At the first examination, the heart being but little excited, I discovered a slight murmur just to the left of the apex, heard only during the latter part of each inspiratory act. I could discover no murmur at the base. At a subsequent examination on the same day, made after dinner, the patient having drunk a little wine with his dinner, the action of the heart was much greater than at the previous examination. I then discovered a well-marked systolic murmur at the apex, to the left of the apex and at the lower angle of the scapula; I also ascertained the existence of a soft systolic murmur at the base on the left side of the sternum and not on the right side. This murmur extended over the whole summit of the chest on the left side. At the summit it came evidently from the subclavian, as the pitch differed from that of the murmur over the pulmonary artery, i.e., in the 2 nd intercostal space on the left side.

On the next morning, I made an examination while the patient was still in bed. The heart was then acting tranquilly. I discovered a feeble murmur at the apex only; this murmur was not perceived behind, and no murmur was heard at the base. The aortic and pulmonic second sounds were normal, and so also were the mitral and tricuspid valvular elements of the first sound.

I shall quote from my record book the remarks which were appended to this case when the record was made:

“The heart is but little if at all enlarged, and the heart sounds abnormal. There exist, therefore, no lesions which at present are of serious import. The cardiac trouble which has occasioned the patient so much unhappiness and anxiety is purely functional. Dr. (who first examined this patient) evidently discovered a murmur. His examination was not very critical, and was made after the patient had just mounted stairs at his hotel. The opinion that there was organic disease without any qualifying explanations produced a profound moral impression on the patient. The opinion of Dr. _________ subsequently did something toward revealing the apprehensions of the patient; but his coming such a long distance to consult me is evidence how much his mind was ill at ease on the subject.

The heart is not entirely free from lesions; there is slight mitral re-gurgitation. The murmur at the base is perhaps inorganic, or at all events it does not denote important valvular lesions, since a comparison of the aortic and pulmonic sounds show the two to be in a normal relation to each other. The lesions in fact which exist in the case are of no immediate seriousness, and of this I assured the patient in the most positive manner.

This case affords an illustration of the importance of discriminating between functional disorder and the effects of organic disease when there is evidence of the latter. It illustrates, also, the importance of the heart sounds and of the size of the heart in determining the gravity of lesions. The evils which may arise from the lesions (if they ever occur) are remote, and I felt warranted in assuring the patient that his condition involved no present danger, and that he might dismiss all thoughts of disease of the heart. I ordered him to live well and to resume his out-door sports. His apprehensions were entirely relieved by my assurances, and his expressions of gratification afforded evidence of what he had suffered mentally from the idea of an organic disease incapacitating him from the duties of life and rendering him liable to sudden death.”

As I have said, this case is a type of a class of cases of not infrequent occurrence. The existence of a cardiac murmur was discovered in consequence of an examination with reference to the lungs. Prior to this time, no symptoms of disorder of the heart existed; the discovery of the murmur was an unfortunate circumstance for the patient; the belief that he had serious disease of the heart became fixed in his mind, and doubtless contributed to the disorder which subsequently occurred. The functional disorder was slight in comparison with cases which are of daily occurrence; but the patient naturally attributed it to organic disease. The affection was in fact altogether functional, albeit the existence of an organic murmur; this is the practical point which the case is intended to illustrate.

* Excerpted from Willus, F.A., & Keyes, T.E., 1941. CARDIAC CLASSICS: A Collection of Classic Works on the Heart and Circulation with Comprehensive Biographic Accounts of the Authors. St. Louis, Mo; C.V. Mosby Company.