|HISTORY OF MEDICINE
|Year : 2012 | Volume
| Issue : 1 | Page : 26-28
Classics in cardiology: On cardiac murmurs* (Part 2)
Professor of the Principles and Practice of Medicine in the Bettevue, Medical College, N. Y., and in the Long Island College Hospital,
|Date of Web Publication||26-May-2012|
Professor of the Principles and Practice of Medicine in the Bettevue, Medical College, N. Y., and in the Long Island College Hospital
|How to cite this article:|
Flint A. Classics in cardiology: On cardiac murmurs* (Part 2). Heart Views 2012;13:26-8
I propose now to consider certain practical points pertaining to the cardiac murmur separately; I shall limit my remarks mainly to the murmurs produced by the blood-currents, in the left side of the heart, viz., the aortic direct, the aortic regurgitant, the mitral systolic and the mitral direct. Exclusive of the pulmonic direct murmur I have but little practical acquaintance with murmurs emanating from the right side of the heart.
Aortic Direct Murmur
The question whether a murmur is organic or inorganic has reference generally to a murmur produced by the current of blood from the left ventricle into the aorta. The aortic regurgitant murmur and a mitral murmur which is truly regurgitant are of necessity organic; they require lesions involving more or less insufficiency of the valves. The mitral direct murmur, as will be seen presently, is inorganic only as a rare exception to the rule. A practical point, then, in certain cases, is to determine whether an existing aortic direct murmur be organic, i.e., dependent on lesions, or whether it be inorganic, i.e., dependent on a blood change. This point cannot always be positively settled, but when such is the case it is practically not very important that it should be settled; in other words, when a murmur exists concerning which we are at a loss to decide whether it be organic or inorganic, if it be the former, the lesion giving rise to it must be trivial, since under these circumstances the heart sounds will be found to be normal and the heart not enlarged. If in connection with an aortic direct murmur, we find the aortic second sound impaired and the heart enlarged, we are warranted in considering the murmur organic. But a slight rippling of the current by roughening from an atheromatous or calcareous deposit which occasions no obstruction, and no valvular insufficiency, may yield a murmur. How are we to distinguish this from an inorganic murmur? The absence of the anemic state of other cardiac murmurs of arterial murmurs, of the venous hum, and the persistency and uniformity of the murmur are the circumstances which render it probable that it is organic; while the existence of anemia, of other cardiac murmurs, of arterial murmurs and the venous hum, together with intermittency and variableness of the murmur, render it probable that it is inorganic.
In my work on diseases of the heart, 1859, I have stated roughness of the murmur to be one of the circumstances showing it to be organic. I then believed that an inorganic murmur was never rough. The able reviewer of my work in the Dublin Quarterly says, with regard to this point, "We are unable to give unqualified assent to the statement that an inorganic murmur is uniformly soft." The criticism of the reviewer is just; I was mistaken in the statement as the following case will show:
I visited in May, 1860, a female patient who presented a loud rasping murmur, which had led to the suspicion of aneurism. The patient was exceedingly anemic; there was total loss of appetite with vomiting and diarrhea. The anemia could not be accounted for; it belonged in the category of cases described by Addison as cases of idiopathic anemia. I found a rough rasping murmur at the base of the heart on the right of the sternum, and a similar murmur was heard over the subclavian and carotid. On examination after death, in this case, the heart was perfectly normal, the aortic orifice, the aorta, subclavians, and carotids were free from any morbid change, and the lungs were healthy. The murmur was evidently due to a blood change.
The discrimination of an aortic, direct from a pulmonic direct murmur is a point of interest. If the normal situation of the aortic and pulmonic artery in relation to the walls of the chest be preserved, all aortic direct murmur has its maximum of intensity and may be limited to the point where the aorta is nearest the surface, viz., the second intercostal space on the right side close to the sternum. But the normal relation of the vessels to the thoracic walls is not infrequently changed when the heart becomes enlarged, or as a consequence of past or present pulmonary disease, and hence this murmur may be loudest or limited to the base on the left side of the sternum. The situation of the murmur or of its maximum, therefore, is not always reliable in the discrimination. A pulmonic direct murmur has its maximum or is limited to the second or third intercostal spaces on the left side close to the sternum, the artery being at these points nearest the surface, but, as just stated, an aortic direct murmur may be found to be loudest in this situation.
If the heart be not enlarged or displaced by pressure from below the diaphragm, the chest not depressed, and the lungs are free from disease, the fact that a murmur has its maximum at or is limited to the right side of the sternum, is evidence of its being aortic rather than pulmonic, and per contra, the fact of a murmur having its maximum at or being limited to the left side of the sternum, is evidence of its being pulmonic rather than aortic. But, the propagation of the murmur into the carotid is the most important circumstance in this discrimination. An aortic direct murmur, unless it is quite weak, is generally propagated into the carotid. A pulmonic direct murmur of course cannot be. Here attention to the pitch and quality of sound is called into requisition. It is to be determined that a murmur heard over the carotid is propagated from the aorta not produced within the carotid. How is this to be determined? Very easily in most cases, by a simple comparison of the murmur as heard over the carotid and at the aortic orifice. If the murmur in the neck be a propagated murmur it will differ from that at the base of the heart chiefly as regards intensity; the pitch and quality will not be materially changed. If it be rough or soft at the base of the heart, it will be the same in the neck, if the pitch be high or low at the base of the heart, it will be the same in the neck. On the other hand, a murmur produced within the carotid, will be likely, in the great majority of cases to differ in quality and pitch from a coexisting murmur at the aortic orifice.
In accordance with what has been stated with reference to the limitations of the significance of organic murmurs in general, an aortic direct murmur, when undoubtedly organic, alone affords little or no information respecting the nature and extent of the lesions which give rise to it. A comparison of the aortic with the pulmonic second sound of the heart enables us frequently to form an opinion as regards the amount of damage which the aortic valve may have sustained. The aortic second sound, in health, as heard in the right second intercostal space near the sternum, is more intense, and has a more marked valvular quality, than the pulmonic second sound as heard in corresponding situation on the left side. Now, it is often easy to determine whether the intensity of the aortic second sound is diminished and its valvular quality impaired; and in proportion all this sound is abnormally altered in these respects, we may infer that the aortic valve is damaged. It is hardly necessary to say that, in order for this comparison to warrant the inference just stated, pulmonary disease must be excluded. A tuberculous deposit, for example, on the left side, may, by conduction, render the pulmonic apparently more intense than the aortic sound, the latter retaining its normal intensity; the same will occur from shrinking of the upper lobe of the left lung so as to bring the pulmonary artery into contact with the thoracic walls. Under the latter circumstances the pulsation of the pulmonic artery may sometimes be distinctly felt in the second left intercostal space near the sternum.
I have met with two cases during the past winter in which the pulsation of the pulmonic artery was so strong as to suggest the idea of aneurism; in both cases, the patients were affected with tuberculous disease of the left lung. Alteration of the normal relation of the aorta and pulmonic artery clue to enlargement of the heart, or to any of the causes already mentioned, will of course preclude a comparison of the two sounds.
With reference to the value of a comparison of the aortic and pulmonic second sound in estimating the amount of aortic lesions, I state that the normal intensity and purity of the aortic second sound warrant the exclusion of lesions affecting it, i.e., the valve, sufficiently to give rise to obstruction. I do not say that contraction of the aortic orifice may not occur without involving the aortic valve, and, in such a case, the aortic second sound may remain intact. In fact, I imply this when I proceed to say, "In a large proportion of the cases of obstructive lesions of the aortic orifice, the valve is involved sufficiently to compromise, to a greater or less extent, its function and impair the intensity of the aortic second sound." This language is equivalent to admitting that there are a small proportion of cases of obstructive lesions of the aortic orifice, in which the valve is not involved sufficiently to compromise its function and impair the intensity of the aortic second sound. These exceptional cases are extremely rare. Surely the able reviewer will admit that, in the great majority of cases, the valve is involved so as to impair its function to a greater or less extent.
I have lately been interested in a nice point of observation connected with the murmur under consideration, viz., the concurrence of two aortic direct murmurs, one produced at the aortic orifice and another within the aorta just above the orifice. One of the murmurs may be organic and the other inorganic or both murmurs may be organic. At the present moment, I have under observation 3 cases of endocarditis with rheumatism, each presenting a high pitched basic murmur when the stethoscope is placed over the sternum and a little to the right of the median line, the murmur limited to a circumscribed space, and just above this point, in the right second intercostal space, is another murmur differing from the former notably ill pitch, being quite low. In one of these cases, there is still another murmur in the pulmonic artery. The high pitched murmur just below the second intercostal space, as I infer from the situation to which it is limited, is a murmur produced at the aortic orifice and the low pitched murmur just above, as I infer, also, from the situation to which it is limited, is an aortic murmur produced within the artery above the aortic orifice. I infer that there are two murmurs from the notable difference in pitch, it being by no means probable that a single sound would be so much altered within the area in which the two murmurs are heard, this area not being larger than a half dollar. That an aortic murmur is sometimes produced at the orifice and sometimes within the artery above the orifice, in different cases, is certain, but I am not aware that the production of a murmur in each situation, at the same time, in the same case, and the discrimination of the two by means of the character of the sound, have been pointed out.
| Aortic Regurgitant Murmur|| |
This murmur need never, as a matter of course, be confounded with the systolic murmurs, viz., the aortic direct, and. mitral regurgitant, the latter occurring with the first, and the former with the second sound of the heart. In general, too, there is no difficulty in distinguishing the aortic regurgitant, from the mitral direct murmur. The former occurs with and follows the second sound, the latter precedes the first sound. The one is diastolic, the other is pre-systolic. This is a distinction, nice, it is true, but easily appreciable in practice, to which I shall recur under the heading of the mitral direct murmur.
The situation of the murmur is also distinctive. It is best heard at, and below the base of the heart. Usually, it is best heard below the base to the left of the median line on a level with the third or fourth rills. This is doubted by the reviewer in the Dublin Quarterly, to whom I have referred, but as the statement is based on a pretty large number of recorded observations, I must consider it as correct. It is not uncommon to hear this murmur distinctly, and even loudly, over the apex; it may be diffused over the whole praecordia and even propagated beyond this region. An aortic murmur with the second sound at the heart, propagated below the base of the heart, necessarily implies regurgitation, in other words there must be insufficiency of the aortic valvular segments. But, it is always to be borne in mind that no inference can be drawn from the intensity or character of the murmur, respecting the amount of insufficiency and consequent regurgitation. An extremely small regurgitant stream may give rise to a loud murmur, while a feeble murmur may accompany a large regurgitant current, as the rippling brook is noisy while the deep broad river flows silently. In a case recently under observation, there existed a loud aortic regurgitant murmur, and on examination after death the aortic segments were so slightly impaired that, on cursory inspection, they might have been considered as normal. Weakening or extinction of the aortic second sound of the heart, are points of importance as showing frequently the extent to which the function of the aortic valve is impaired. Comparison with the pulmonic sound enables us to judge whether the aortic sound be impaired, provided the pulmonic sound be not abnormally intensified as a result of coexisting mitral lesions. It is important to recollect that when aortic and mitral lesions coexist, the intensity of the pulmonic sound cannot be taken as a criterion for judging whether the aortic sound be, or be not weakened.
This remark is equally applicable to the comparison in cases in which an aortic direct murmur is present. It is needless to say that in comparing the aortic and pulmonic sound in connection with an aortic regurgitant, as with an aortic direct murmur, pulmonary disease is to be excluded, i.e., solidification or shrinking of the left lung will, as already stated, render the pulmonic sound relatively more intense than the aortic, irrespective of, on the one hand, any actual increase of the intensity of that sound, or, on the other hand, of any weakening of the aortic sound. It is also to be stated here, as heretofore, that an alteration of the situation of the aorta and pulmonary artery as regards the thoracic walls, due to enlargement of the heart, or other causes, will preclude a comparison of the two sounds with reference either to intensification of the pulmonic, or weakening of the aortic sound.