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The Clinical Significance of Heart Murmurs in Children
THE CLINICAL SIGNIFICANCE OF HEART MURMURS IN CHILDREN STANLEY GIBSON,
M.D.*
IT would seem appropriate to preface any discussion of heart murmurs with an apology. Perhaps there is no other phase of the physical examination of the patient in which the personal factor enters to the extent that it does in the practice of auscultation of the heart. It is doubtful whether any two individuals are endowed with the same ability to estimate the intensity, quality and pitch of heart murmurs. Even though two individuals may agree in general as to the character of an abnormal sound, they may yet disagree as to its significance. On the other hand, different examiners may not be in complete agreement as to the nature of the sounds heard and yet be in agreement as to the underlying pathology. There is no substitute for experience in the evaluation of heart murmurs, and this experience must include a large number of cases followed to the postmortem room. In spite of the difficulties involved, heart murmurs are sufficiently important to merit special study. I have little patience with that school of cardiologists which teaches that murmurs are of little moment and that attention should be focused chiefly upon the amount of work which the heart is able to do. I have equally little patience with the physician who is so intent upon an abnormal sound in the heart that he neglects other means of examination. The electrocardiogram, the x-ray, the determination of function are all important, and it cannot be too strongly emphasized that auscultation is only one feature of the cardiac examination. I should like to add, however, that at least in children it is the most important single feature. Moreover, the evaluation of abnormal cardiac sounds in children requires a different approach from that which one uses in the adult. One wants to know first of all whether the child has heart disease. If he has heart disease it is important to know the cause, for the management of the child is to a great degree dependent upon the etiology of the cardiac ailment. It is my firm conviction that in answering these questions a careful evaluation of the murmur or murmurs heard yields more inf~rmation than any other single method of examination. If any physician will recall his peqonal experience I think he will agree that in most instances where a question of heart disease in childhood has From The Children's Memorial Hospital, Chicago . .. Professor of Pediatrics and Chairman of the Department of Pediatrics, Northwestern University Medical School; Physician-in-Chief, The Children's Memorial llospital, Chicago. 35
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STANLEY GIBSON
brought out conflicting opinions the discussion has usually revolved about the significance of a cardiac murmur. TECHNIC OF EXAMINATION
The technic of auscultation of the heart in infancy and childhood is important. It goes without saying that the examination will be unsatisfactory, or even worthless, if the patient is crying. Few of us have escaped the embarrassment of missing heart murmurs in young babies only to hear them so loudly at a subsequent examination that we can be morally certain that they did not develop during the interval. Occasionally in babies one must wait until they are asleep before a satisfactory examination can be made. ~,cl1iJd"whQjSJl~rvsr\ls. a1).(i a.l?P!~h~nsjye, JIH!Y. ,s.l,l~", .~"n1l:lr1!lux_-",l,l!ch ,will, become .less marked or c2..n:!E!et~.Y disapp"earw:h~. th.e heart quiets. down. It should be an invariable rule to examine each patient in the supive p'osltiOn.:He should also be examined in the left l.at~ral and in the sitting positions. In~~£h .as the transmission of a murmur may give a Slue "as to its origin, it is important to listen in various directions from the point of maximum intensity, including the right side of the chest and the back. FUNCTIONAL MURMURS
Heart murmurs are so frequent during the period of childhood that even in a well child the absence of a murmur rather than its presence occasions surprise. These murmurs are variously spoken of as accidental, functional or physiological, the inference being that they occur in the absence of organic involvement of the heart. These innocent murmurs have certain characteristics which usually enable one to distinguish them from organic murmurs. The most frequent functional murmur is that which occurs in the second left interspace over the pulmonary area. This murmur is sys~()lic in time,
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
37
When they are fairly loud, differentiation from organic murmurs may be more difficult. Yet if one keeps in mind the location, the timing and the characteristics of these murmurs as mentioned above it is usually possible to arrive at a satisfactory decision. tt}., some instances, however, a murmur must be followed for years before it can be stated Wltli'reasonable certainty wheJIler it is functional or organic. Itn:ls my opportunity, together with my colleagues in the cardiac clinic, to follow over a period of years a large number of children with murmurs such as I have described. It has been our experience that the great majority of these murmurs have become less distinct or have disappeared altogether at the approach of adolescence. Only rarely have they become more intense and taken on the quality of organic murmurs. Closely related to the type of murmur described above is that which is encountered in children who are ill but in whom there is no evidence of cardiac involvement. I refer to the murmurs which are often sEoken of as hernic, namely, thoseoccllrdng 'in'-the ~ne-~i;s, in the presence of fever, and various other conditions in which the heart may be temporarily affected by disease elsewhere. The fact that such murmurs become less distinct or disappear as the child's general condition improves is convincing evidence of their nature. Sounds Sometimes Confused with Murmurs.-A word should be said at this point concerning certain sounds which are unimportant except for the fact that they are sometimes confused with murmurs. The most important is the y!!!:.0us bum. It is a blowing or roaring sound, continuous throughout the cardiac cycle, best heard in the neck, and more intense on the right side of the neck than on the left. Confusion may arise from the fact that this hum may extend down over the chest, and if heard on the left side may be confused with the continuous murmur of patent ductus arteriosus. Yet the differential diagnosis is easy. The venous hum is loudest in the ,sitting position. It is much less loud or may even disappear when the patient is lying down. It also varies in intensity when the head is turned from side to side. Finally, pressure over the neck veins obstructing the flow of blood causes the hum to disappear. It is well to remember that such a sound does occur. More than once I have seen the diagnosis of patent ductus arteriosus made because of unfamiliarity with the characteristics of the venous hum. There are other adventitious sounds which may occasionally occur in the cardiac area. One of these is a so-called "click" which may be heard at some point in the cardiac cycle. The origin may be obscure. In some instances at least the sound seems to be due to the sudden forcing of air from alveoli of the lung adjacent to the heart. There are also occasional whistling sounds heard over the precordium which may possibly be due to aberrant chordae tendineae.
been
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STANLEY mBSON
MURMURS OF ORGANIC HEART DISEASE
In evaluating the murmurs due to organic heart disease it is essential first of all to be familiar with the pathological lesions which occur in the heart of a child. With few exceptions these lesions are due either to c.2.ng~nital or rheumatic heart disease. . Congenital Heart Disease.-At the very basis of an understandmg of congenital anomalies of the heart is an appreciation of the fact that in the great majority of instances there is an abnormal communication between the systemic and venous circulations. Ther~~ are three common avenurs of communicatio?;-~.__ ddect of the I. interventricular s~~m, arl.l~~.i?!:al1len_QV(lI~,\:?6.L(l_. patent ductus ateriosus. Their importance in the pathology of congenital heart disease is attested by the statistics of Abbott who found in an analysis of 1000 cases that existing alone or in combination with other lesions there were 257 examples of defect of the interventricular septum, 290 of open foramen ovale, and 242 of patent ductus arteriosus. The passage of blood through anyone of these openings may give rise to a murmur. In at least two of these conditions the murmur is so characteristic that the diagnosis can be made with confidence in most instances. 11!.. a.)qca#zed defect of the interventricular septum one hears a ITstoli<: murmur maximum in the third to fourth interspaces just to the left of the sternum, This murmur is harsh in character and is usua!!Y._FJ~dytrans~itt~d. fn~:w_~llmark<:d cases.a.sy~toli.c thrill can he f~Jh.e area of maxirpu!ILinJe.m!rYQf th.~rnJJJ.mur. This murmur is usually heard as soon as the infant is horn, and remains constant throughout childhood. In a series of twelve infants and children coming to autopsy at The Children's Memorial Hospital in whom a defect of the interventricular septum was found, the typical systolic murmur described above had been noted in eleven cases. In the remaining one the infant was moribund on admission to the hospital and the physical examination was not completed. Perhaps the most remarkable murmur in the entire field of cardiology is that which occurs in typical cases of pgtent dU.ctus arteriosus. This murmur is best heard in the first and second left interspaces. It iS~.h~~!d through practically the entire cardiac cycle, though louder In systole than in diastole. It is harsh and rumbling and has been variously described as h.!!!!!~il1g top, machinery, rpill wheel, tunnel, and rolling thunder in character. It is 'us'uaIly accompanied by a thrill. Although this murmur when occurring in typical form is diagnostic of patent ductus arteriosus it is worthy of emphasis that the characteristic murmur is of slow evolution. I have never heard a humming top murmur in a newborn infant. We have been fortunate in having had the opportunity to follow from birth a number of infants who subsequently proved to have the typical findings of a patent ductus. In the majority no murmur was descrihed in the early months of life. In
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
39
others a systolic murmur was noted. And in practically all cases a systolic murmur was the only one described during the first year of life. At some time during the second year a diastolic phase of the murmur was usually recorded, an.~ the typical continuous roaring murmur was ordinarily noted by the second or third year. A few months ago a baby 6 months of age was admitted to the hospital with symptoms and signs of congenital heart disease. There was marked cardiac enlargement, cyanosis on crying, and a harsh murmur chiefly in systole, but with a distinct diastolic phase heard in the first and second left interspaces. It was our opinion that a patent ductus arteriosus was present. The baby came to autopsy. The diagnosis of patent ductus was confirmed at autopsy, and there was in addition a fairly large open foramen ovale. This is the only instance in which I have heard a definite humming top murmur in a patient under 1 year of age. Increased interest has been aroused recently in the subject of patent ductus arteriosus because of the numerous instances of successful ligation following the development of this operation by Dr. Robert E. Gross of Boston. It should be emphasized, however, that the presence of the typical murmur does not in itself constitute an indication for operative interference. Other criteria must be fulfilled. In cases ofq'p'~ntoramen ovale there is less uniformity of o~inion as to whether a murmur occurs, and if so whether it is suffiCIently characteristic to be regarded as diagnostic. The contraction of the auricles is relatively feeble and the difference in blood pressure between the chambers is not great. One can easily imagine that a fairly large open foramen might exist without the transference of a sufficient amount of blood at a velocity which would produce a murmur. One sees at autopsy not infrequently a physiologically patent foramen ovale where no murmur had been noted during life. On the other hand, I have seen two instances in which a loud systolic murmur best heard in the second and third left interspaces was heard by numerous observers over a period of years and at autopsy the only abnormal finding was a large open foramen ovale. In these cases a defect of the interventricular septum had been suspected. In summary, then, it may be said that of the three common lesions which allow of mixture of arterial and venous blood, the diagnosis of two, namclydefect .of the interventricular septum and patent ductus l,lxreriosus, ca,n be made with a good deal of assurance when they exist i!.LP11reJorm. Where more than one of these lesions exists in the same individual or where one of them occurs in combination with some other anomaly, the resulting murmur or murmurs produced by the passage of blood through two or more abnormal openings may leave doubt as to the exact origin. A classical example is the..t.etralQgyof F allQt.. In this condition there is both a defect of the interventricular' septu~ and stenosis of the pulmonary artery. Under such conditions one cannot say to what extent each of these lesions contributes to the
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STANLEY GIBSON
precordial murmur which is heard in the tetralogy. The situation may be still further complicated by the fact that an open foramen ovale or a patent ductus may be present in addition to the other lesions. In such circumstances the diagnosis must be determined by other means such as the presence or absence of cyanosis, the x-ray silhouette, and the electrocardiogram. In the absence of an abnormal communication between the systemic and venous circulations, murmurs due to congenital lesions may still occur. Pulmonary stenosis may occur as a single lesion though it is relatively rare. In this condition one hears a systolic murmur maximum at the second left interspace, usually harsh in character, though the quality and transmission of the murmur will naturally depend upon the degree of stenosis. Congenital subaortic stenosis is a more frequent lesion, though by no means common. It is manifested by a harsh systolic murmur best heard in the first and second right interspaces and often accompanied by a thrill. Often times a thrill may be palpated in the suprasternal notch when it cannot be felt over the aortic area. At this point it may be well to mention the occurrence of murmurs in conditions of heart strain in which the essential pathologic changes lie outside the heart. One such condition is the adult type of coarctation of the aorta. The pathology consists of an abrupt narrowing of the aorta as if a string were tied tightly around it. The narrowing usually occurs beyond the origin of the great vessels of the arch at about the point of insertion of the ductus arteriosus. Theoretically one would anticipate a characteristic murmur at the base of the heart. In practice we have not found this to be true. It has been my privilege to observe some fifteen children with coarctation of the aorta. The striking feature has been the variability of the auscultatory findings in these children. A murmur has usually been present. Most often it has been systolic, sometimes in the second interspace, sometimes at the third left interspace, and other times at the apex. In one instance systolic and mid-diastolic murmurs were heard near the apex, closely simulating rheumatic heart disease. In one patient a diastolic murmur was heard along the left sternal margin beginning with the second sound such as is usually heard in aortic insufficiency. It was our suspicion that this may have been due to a bicuspid aortic valve which is known to be a frequent accompaniment of coarctation of the aorta. Of course one cannot make the diagnosis of coarctation of the aorta by auscultation of the heart. Yet the fact that one hears a murmur over the heart which does not fit into the usual pattern of either congenital or acquired heart disease should arouse one's suspicions. The diagnosis is made by the increased blood pressure in the arms, weakened or absent femoral pulsations, with lowered or unobtainable blood pressure in the legs, throbbing of the intercostal arteries and scalloping of the ribs on x-ray examination.
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
41
A second condition producing heart strain is that in which there is hypertension in the pulmonary circuit producing dilatation of the pulmonary artery. In this condition a diastolic murmur due to pulmonary regurgitation may occasionally be heard in the second left interspace although a murmur is not ordinarily present. In one patient who had decreased exercise tolerance, intermittent cyanosis, and retarded growth a diastolic murmur was heard in the second left interspace. Autopsy revealed a huge pulmonary artery with relatively insufficient pulmonary valve, and the microscopic examination revealed primary proliferative arteriolar sclerosis of the pulmonary vessels. Rheumatic Heart Disease.-Let us now turn to a consideration of the murmurs which one encounters in rheumatic heart disease. Here again one must be familiar with the underlying pathology. Numerous postmortem studies have established the fact that in rheumatic invasion of the heart the mitral valve. is practically always involved. Hence it is necessary to dir-ect one;s attention to the murmurs which are produced by the inflammatory changes in the leaflets of this valve. I.Q.s_utficiency of the mitral valve occurs early. It is manifested by a systolic murmur, usually soft and blowing in character, which is transmitted to the left. This murmur is oftentimes heard within a few days of the onset of the first symptoms of rheumatic fever. It is doubtful whether this early murmur is due to changes in the leaflets of the valve; it is probably due to relative insufficiency due to cardiac dilatation. The myocardium is regularly involved in the rheumatic assault upon the heart and is often of more serious moment than the valvular involvement. On this account early dilatation of the heart is to be expected. Whether the systolic murmur at the apex in the early course of rheumatic heart disease is due merely to stretching of the valve or whether it is due to an inflammatory process in the valve itself is after all largely a didactic question. 1he appearance of such a murmur in a heart previously known to be clear at the apex is presumptive evidence of rheuniatl<;. h~art disease. If such a murmur persists for weeks or months after the acute rheumatic episode has susbided one can then feel fairly certain that the mitral valve has suffered permanent damage. This ~urmur is usually more distinct in the lying than in the sitting position and is oftentimes still better heard when the patient is turned on the left side. --Wit:hi~a short time of the appearance of the systolic murmur, an early diastolic rumble may be heard. It occurs at a barely appreciable interval after the second sound, occupying in the cardiac cycle the position of the third heart sound. It is of short duration, is rumbling rather than blowing, and is usually quite localized at or near the apex. In the absence of marked cardiac dilatation this murmur is looked U.QQ.!L:J,S reasonably definite eVIdence of· mitral involvement. Months or years after the appearance of the first signs of mitral damagea-rhird m1.i~lllur may become evident. Thi~is t~eJamiIiarpresystolic mllrmur.
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STANLEY GIBSON
which is rumbling in character beginning at an appreciable interval after the second sound and ending abruptly with the first heart sound. The presystolic murmur is often quite localized at or near the apex and may be missed entirely unless one listens carefully in and about the apical region. It is much better heard in the s,!!pil1e position than when the patient is sitting, and may in some instances become· audible only in the left lateral position. There are then three murmurs which may be heard at the apex due to rheumatic involvement of the mitral valve. In the milder cases only the systolic murmur may be heard. In others the mid-diastolic murmur is also heard. In still others a presystolic murmur becomes evident. At times all three murmurs may be heard at one time. In some instances the valve may apparently heal, so that the murmurs previously heard may disappear. This is particularly true in the case of the systolic and mid-diastolic murmurs although once the presystolic murmur is well heard it is usually a permanent finding. In addition to involvement of the m~y!!!ye the !l()..!'ti.c. Y;llye is also frequently invaded in the rheumatic process. The lesion at least in its early stages is chiefly that of insufficiency and is manifested by a c!ie~~.Qlic .murmur, u~~gllY blowing in charact.er, ~~.gipning with the second soun~, bestheard in the third and fourth interspaces along the ~lfsternaImargln. It is important to emphasize the fact that this murmur in children should be sought along the left sternal margin and not over the aortic area. The aortic murmur is much better heard with the Bowles type of stethoscope than with the bell, and in my own experience the naked ear applied to the chest is the best means of all. In early cases the murmur is very short, soft and localized and will be missed unless a careful examination is made. It is distinguished from the diastolic murmurs of mitral disease by its location and by the fact that it begins with or immediately after the second heart sound. Stenosis also occurs in rheumatic involvement of the aortic valve though it is seldom clinically evident in children. Its presence is indicated by a harsh, rough systolic murmur which is heard best in the first and second right interspaces near the sternal margin. Involvement of the tricuspid valve is not unusual, but it is usually of lesser extent than the accompanying mitral involvement and the findings are so nearly identical with those arising at the mitral valve that diagnosis is seldom possible. The pulmonary valve may occasionally show slight involvement at postmortem examination, but clinical evidence is practically never present during life. Finally, attention should be called to the pericardial friction rub which occurs in acute pericarditis. Typically it is a to-and-fro sound which is harsh, rasping or leathery in character, often louder in systole than in diastole. The sound may be heard over the entire precordiuIll, or even beyond, and may sometimes be heard in the back. It may completely obscure any cardiac murmurs which may be present. On
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
43
the other hand, the friction rub may be very localized, llIay occur in only one phase of the cardiac cycle, and may be so soft that it is difficult to differentiate from a heart murmur. In doubtful cases repeated examinations may be necessary. The friction rub is transient, and changes in quality and location from day to day. Heart murmurs remain relatively unchanged over longer periods of time. Summary and Differential Diagnosis.-Having outlined the characteristics of the murmurs which are encountered in congenital heart disease and in rheumatic heart disease, let us attempt a brief summary, and consider the differential diagnosis. IE-S()~s:en~t~llle!!r"tAiseas~ _tQe murmur of interventricular septal defect is systolic in time, maxImumin -the-thIrd and fourth left interspaces I~ediar to the apex; th~! Dropen foramen ovale (when it is present) iuystalic...jorime, ~est hear(rIn- the-second and third left ip.terspaces; the murmur of aortic stenosis"issystor!~JQ--tiijie- arid-maximum in the-second rIght intersp·~ice; -rFiat-of.21!Jl1)911i£stenosis ()ccurs in systole with its greatest intensIty in the second left interspace; the murmur of a patent ductus arterIOSUS is continuous and is loudest in the first and second left interspaces. In rheumatic heart disease, systolic. and diastolic rnurmurs are heard at -the apex -when die mitral valve is "involved, and a diastolic murmur iSliearanear the- sternum in the third and fourth'lnterspaces in ins~lenc:y"or.ihe aortic valve. - . It will thus be noted that the murmurs of congenital heart disease are loudest over the body of the heart or at the base rather than at the apex. It will also be noted that with the single exception of the continuous murmur of patent ductus arteriosus those mentioned are all systolic in time. In contrast, the one important systolic murmur in rheumatic heart disease in children is maximum at the apex. Diastolic murmurs may be heard at the apex in mitral involvement, and along the left sternal margin in the third and fourth interspaces in aortic involvement. In sh()rt, a systolic murmur best heard above. the apex is Eresumptive evidence otcongenital heart disease, while a diastOllcmurmur either at the apex or above it (save for the "cII;istollc phaseth-e murmur of patent ductus arteriosus) is suggestive of rheumatic involvement in the heart. -_."" ..... In typical cases the differential diagnosis can usually be made by a study of the murmurs alone. It should not be forgotten, however, that both congenital and rheumatic heart disease may exist in the same individual. This may confuse the picture. Moreover, as was emphasized in the beginning, other means of diagnosis must not be neglected. The patient's age and history are important. An organic murmur heard during the first year of life is practically always due to a congenital defect, aQgyp to the age ()f }year~ [heumatit:: invasion of the heart is infreqtlent. The history or the presence of joint pains, rheumatic-· nodules, chorea or of annular erythema suggests rheumatic in-
ot
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STANLEY GIBSON
fection, and would naturally in the case of doubtful physical signs in the heart influence one in favor of a rheumatic cardiac involvement. Finally, the entire patient, not merely the heart, should be examined, and the use of x-ray, the electrocardiogram and other laboratory means should be employed as necessary to complete the diagnostic study.
M.D.*
IT would seem appropriate to preface any discussion of heart murmurs with an apology. Perhaps there is no other phase of the physical examination of the patient in which the personal factor enters to the extent that it does in the practice of auscultation of the heart. It is doubtful whether any two individuals are endowed with the same ability to estimate the intensity, quality and pitch of heart murmurs. Even though two individuals may agree in general as to the character of an abnormal sound, they may yet disagree as to its significance. On the other hand, different examiners may not be in complete agreement as to the nature of the sounds heard and yet be in agreement as to the underlying pathology. There is no substitute for experience in the evaluation of heart murmurs, and this experience must include a large number of cases followed to the postmortem room. In spite of the difficulties involved, heart murmurs are sufficiently important to merit special study. I have little patience with that school of cardiologists which teaches that murmurs are of little moment and that attention should be focused chiefly upon the amount of work which the heart is able to do. I have equally little patience with the physician who is so intent upon an abnormal sound in the heart that he neglects other means of examination. The electrocardiogram, the x-ray, the determination of function are all important, and it cannot be too strongly emphasized that auscultation is only one feature of the cardiac examination. I should like to add, however, that at least in children it is the most important single feature. Moreover, the evaluation of abnormal cardiac sounds in children requires a different approach from that which one uses in the adult. One wants to know first of all whether the child has heart disease. If he has heart disease it is important to know the cause, for the management of the child is to a great degree dependent upon the etiology of the cardiac ailment. It is my firm conviction that in answering these questions a careful evaluation of the murmur or murmurs heard yields more inf~rmation than any other single method of examination. If any physician will recall his peqonal experience I think he will agree that in most instances where a question of heart disease in childhood has From The Children's Memorial Hospital, Chicago . .. Professor of Pediatrics and Chairman of the Department of Pediatrics, Northwestern University Medical School; Physician-in-Chief, The Children's Memorial llospital, Chicago. 35
36
STANLEY GIBSON
brought out conflicting opinions the discussion has usually revolved about the significance of a cardiac murmur. TECHNIC OF EXAMINATION
The technic of auscultation of the heart in infancy and childhood is important. It goes without saying that the examination will be unsatisfactory, or even worthless, if the patient is crying. Few of us have escaped the embarrassment of missing heart murmurs in young babies only to hear them so loudly at a subsequent examination that we can be morally certain that they did not develop during the interval. Occasionally in babies one must wait until they are asleep before a satisfactory examination can be made. ~,cl1iJd"whQjSJl~rvsr\ls. a1).(i a.l?P!~h~nsjye, JIH!Y. ,s.l,l~", .~"n1l:lr1!lux_-",l,l!ch ,will, become .less marked or c2..n:!E!et~.Y disapp"earw:h~. th.e heart quiets. down. It should be an invariable rule to examine each patient in the supive p'osltiOn.:He should also be examined in the left l.at~ral and in the sitting positions. In~~£h .as the transmission of a murmur may give a Slue "as to its origin, it is important to listen in various directions from the point of maximum intensity, including the right side of the chest and the back. FUNCTIONAL MURMURS
Heart murmurs are so frequent during the period of childhood that even in a well child the absence of a murmur rather than its presence occasions surprise. These murmurs are variously spoken of as accidental, functional or physiological, the inference being that they occur in the absence of organic involvement of the heart. These innocent murmurs have certain characteristics which usually enable one to distinguish them from organic murmurs. The most frequent functional murmur is that which occurs in the second left interspace over the pulmonary area. This murmur is sys~()lic in time,
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
37
When they are fairly loud, differentiation from organic murmurs may be more difficult. Yet if one keeps in mind the location, the timing and the characteristics of these murmurs as mentioned above it is usually possible to arrive at a satisfactory decision. tt}., some instances, however, a murmur must be followed for years before it can be stated Wltli'reasonable certainty wheJIler it is functional or organic. Itn:ls my opportunity, together with my colleagues in the cardiac clinic, to follow over a period of years a large number of children with murmurs such as I have described. It has been our experience that the great majority of these murmurs have become less distinct or have disappeared altogether at the approach of adolescence. Only rarely have they become more intense and taken on the quality of organic murmurs. Closely related to the type of murmur described above is that which is encountered in children who are ill but in whom there is no evidence of cardiac involvement. I refer to the murmurs which are often sEoken of as hernic, namely, thoseoccllrdng 'in'-the ~ne-~i;s, in the presence of fever, and various other conditions in which the heart may be temporarily affected by disease elsewhere. The fact that such murmurs become less distinct or disappear as the child's general condition improves is convincing evidence of their nature. Sounds Sometimes Confused with Murmurs.-A word should be said at this point concerning certain sounds which are unimportant except for the fact that they are sometimes confused with murmurs. The most important is the y!!!:.0us bum. It is a blowing or roaring sound, continuous throughout the cardiac cycle, best heard in the neck, and more intense on the right side of the neck than on the left. Confusion may arise from the fact that this hum may extend down over the chest, and if heard on the left side may be confused with the continuous murmur of patent ductus arteriosus. Yet the differential diagnosis is easy. The venous hum is loudest in the ,sitting position. It is much less loud or may even disappear when the patient is lying down. It also varies in intensity when the head is turned from side to side. Finally, pressure over the neck veins obstructing the flow of blood causes the hum to disappear. It is well to remember that such a sound does occur. More than once I have seen the diagnosis of patent ductus arteriosus made because of unfamiliarity with the characteristics of the venous hum. There are other adventitious sounds which may occasionally occur in the cardiac area. One of these is a so-called "click" which may be heard at some point in the cardiac cycle. The origin may be obscure. In some instances at least the sound seems to be due to the sudden forcing of air from alveoli of the lung adjacent to the heart. There are also occasional whistling sounds heard over the precordium which may possibly be due to aberrant chordae tendineae.
been
38
STANLEY mBSON
MURMURS OF ORGANIC HEART DISEASE
In evaluating the murmurs due to organic heart disease it is essential first of all to be familiar with the pathological lesions which occur in the heart of a child. With few exceptions these lesions are due either to c.2.ng~nital or rheumatic heart disease. . Congenital Heart Disease.-At the very basis of an understandmg of congenital anomalies of the heart is an appreciation of the fact that in the great majority of instances there is an abnormal communication between the systemic and venous circulations. Ther~~ are three common avenurs of communicatio?;-~.__ ddect of the I. interventricular s~~m, arl.l~~.i?!:al1len_QV(lI~,\:?6.L(l_. patent ductus ateriosus. Their importance in the pathology of congenital heart disease is attested by the statistics of Abbott who found in an analysis of 1000 cases that existing alone or in combination with other lesions there were 257 examples of defect of the interventricular septum, 290 of open foramen ovale, and 242 of patent ductus arteriosus. The passage of blood through anyone of these openings may give rise to a murmur. In at least two of these conditions the murmur is so characteristic that the diagnosis can be made with confidence in most instances. 11!.. a.)qca#zed defect of the interventricular septum one hears a ITstoli<: murmur maximum in the third to fourth interspaces just to the left of the sternum, This murmur is harsh in character and is usua!!Y._FJ~dytrans~itt~d. fn~:w_~llmark<:d cases.a.sy~toli.c thrill can he f~Jh.e area of maxirpu!ILinJe.m!rYQf th.~rnJJJ.mur. This murmur is usually heard as soon as the infant is horn, and remains constant throughout childhood. In a series of twelve infants and children coming to autopsy at The Children's Memorial Hospital in whom a defect of the interventricular septum was found, the typical systolic murmur described above had been noted in eleven cases. In the remaining one the infant was moribund on admission to the hospital and the physical examination was not completed. Perhaps the most remarkable murmur in the entire field of cardiology is that which occurs in typical cases of pgtent dU.ctus arteriosus. This murmur is best heard in the first and second left interspaces. It iS~.h~~!d through practically the entire cardiac cycle, though louder In systole than in diastole. It is harsh and rumbling and has been variously described as h.!!!!!~il1g top, machinery, rpill wheel, tunnel, and rolling thunder in character. It is 'us'uaIly accompanied by a thrill. Although this murmur when occurring in typical form is diagnostic of patent ductus arteriosus it is worthy of emphasis that the characteristic murmur is of slow evolution. I have never heard a humming top murmur in a newborn infant. We have been fortunate in having had the opportunity to follow from birth a number of infants who subsequently proved to have the typical findings of a patent ductus. In the majority no murmur was descrihed in the early months of life. In
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
39
others a systolic murmur was noted. And in practically all cases a systolic murmur was the only one described during the first year of life. At some time during the second year a diastolic phase of the murmur was usually recorded, an.~ the typical continuous roaring murmur was ordinarily noted by the second or third year. A few months ago a baby 6 months of age was admitted to the hospital with symptoms and signs of congenital heart disease. There was marked cardiac enlargement, cyanosis on crying, and a harsh murmur chiefly in systole, but with a distinct diastolic phase heard in the first and second left interspaces. It was our opinion that a patent ductus arteriosus was present. The baby came to autopsy. The diagnosis of patent ductus was confirmed at autopsy, and there was in addition a fairly large open foramen ovale. This is the only instance in which I have heard a definite humming top murmur in a patient under 1 year of age. Increased interest has been aroused recently in the subject of patent ductus arteriosus because of the numerous instances of successful ligation following the development of this operation by Dr. Robert E. Gross of Boston. It should be emphasized, however, that the presence of the typical murmur does not in itself constitute an indication for operative interference. Other criteria must be fulfilled. In cases ofq'p'~ntoramen ovale there is less uniformity of o~inion as to whether a murmur occurs, and if so whether it is suffiCIently characteristic to be regarded as diagnostic. The contraction of the auricles is relatively feeble and the difference in blood pressure between the chambers is not great. One can easily imagine that a fairly large open foramen might exist without the transference of a sufficient amount of blood at a velocity which would produce a murmur. One sees at autopsy not infrequently a physiologically patent foramen ovale where no murmur had been noted during life. On the other hand, I have seen two instances in which a loud systolic murmur best heard in the second and third left interspaces was heard by numerous observers over a period of years and at autopsy the only abnormal finding was a large open foramen ovale. In these cases a defect of the interventricular septum had been suspected. In summary, then, it may be said that of the three common lesions which allow of mixture of arterial and venous blood, the diagnosis of two, namclydefect .of the interventricular septum and patent ductus l,lxreriosus, ca,n be made with a good deal of assurance when they exist i!.LP11reJorm. Where more than one of these lesions exists in the same individual or where one of them occurs in combination with some other anomaly, the resulting murmur or murmurs produced by the passage of blood through two or more abnormal openings may leave doubt as to the exact origin. A classical example is the..t.etralQgyof F allQt.. In this condition there is both a defect of the interventricular' septu~ and stenosis of the pulmonary artery. Under such conditions one cannot say to what extent each of these lesions contributes to the
40
STANLEY GIBSON
precordial murmur which is heard in the tetralogy. The situation may be still further complicated by the fact that an open foramen ovale or a patent ductus may be present in addition to the other lesions. In such circumstances the diagnosis must be determined by other means such as the presence or absence of cyanosis, the x-ray silhouette, and the electrocardiogram. In the absence of an abnormal communication between the systemic and venous circulations, murmurs due to congenital lesions may still occur. Pulmonary stenosis may occur as a single lesion though it is relatively rare. In this condition one hears a systolic murmur maximum at the second left interspace, usually harsh in character, though the quality and transmission of the murmur will naturally depend upon the degree of stenosis. Congenital subaortic stenosis is a more frequent lesion, though by no means common. It is manifested by a harsh systolic murmur best heard in the first and second right interspaces and often accompanied by a thrill. Often times a thrill may be palpated in the suprasternal notch when it cannot be felt over the aortic area. At this point it may be well to mention the occurrence of murmurs in conditions of heart strain in which the essential pathologic changes lie outside the heart. One such condition is the adult type of coarctation of the aorta. The pathology consists of an abrupt narrowing of the aorta as if a string were tied tightly around it. The narrowing usually occurs beyond the origin of the great vessels of the arch at about the point of insertion of the ductus arteriosus. Theoretically one would anticipate a characteristic murmur at the base of the heart. In practice we have not found this to be true. It has been my privilege to observe some fifteen children with coarctation of the aorta. The striking feature has been the variability of the auscultatory findings in these children. A murmur has usually been present. Most often it has been systolic, sometimes in the second interspace, sometimes at the third left interspace, and other times at the apex. In one instance systolic and mid-diastolic murmurs were heard near the apex, closely simulating rheumatic heart disease. In one patient a diastolic murmur was heard along the left sternal margin beginning with the second sound such as is usually heard in aortic insufficiency. It was our suspicion that this may have been due to a bicuspid aortic valve which is known to be a frequent accompaniment of coarctation of the aorta. Of course one cannot make the diagnosis of coarctation of the aorta by auscultation of the heart. Yet the fact that one hears a murmur over the heart which does not fit into the usual pattern of either congenital or acquired heart disease should arouse one's suspicions. The diagnosis is made by the increased blood pressure in the arms, weakened or absent femoral pulsations, with lowered or unobtainable blood pressure in the legs, throbbing of the intercostal arteries and scalloping of the ribs on x-ray examination.
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
41
A second condition producing heart strain is that in which there is hypertension in the pulmonary circuit producing dilatation of the pulmonary artery. In this condition a diastolic murmur due to pulmonary regurgitation may occasionally be heard in the second left interspace although a murmur is not ordinarily present. In one patient who had decreased exercise tolerance, intermittent cyanosis, and retarded growth a diastolic murmur was heard in the second left interspace. Autopsy revealed a huge pulmonary artery with relatively insufficient pulmonary valve, and the microscopic examination revealed primary proliferative arteriolar sclerosis of the pulmonary vessels. Rheumatic Heart Disease.-Let us now turn to a consideration of the murmurs which one encounters in rheumatic heart disease. Here again one must be familiar with the underlying pathology. Numerous postmortem studies have established the fact that in rheumatic invasion of the heart the mitral valve. is practically always involved. Hence it is necessary to dir-ect one;s attention to the murmurs which are produced by the inflammatory changes in the leaflets of this valve. I.Q.s_utficiency of the mitral valve occurs early. It is manifested by a systolic murmur, usually soft and blowing in character, which is transmitted to the left. This murmur is oftentimes heard within a few days of the onset of the first symptoms of rheumatic fever. It is doubtful whether this early murmur is due to changes in the leaflets of the valve; it is probably due to relative insufficiency due to cardiac dilatation. The myocardium is regularly involved in the rheumatic assault upon the heart and is often of more serious moment than the valvular involvement. On this account early dilatation of the heart is to be expected. Whether the systolic murmur at the apex in the early course of rheumatic heart disease is due merely to stretching of the valve or whether it is due to an inflammatory process in the valve itself is after all largely a didactic question. 1he appearance of such a murmur in a heart previously known to be clear at the apex is presumptive evidence of rheuniatl<;. h~art disease. If such a murmur persists for weeks or months after the acute rheumatic episode has susbided one can then feel fairly certain that the mitral valve has suffered permanent damage. This ~urmur is usually more distinct in the lying than in the sitting position and is oftentimes still better heard when the patient is turned on the left side. --Wit:hi~a short time of the appearance of the systolic murmur, an early diastolic rumble may be heard. It occurs at a barely appreciable interval after the second sound, occupying in the cardiac cycle the position of the third heart sound. It is of short duration, is rumbling rather than blowing, and is usually quite localized at or near the apex. In the absence of marked cardiac dilatation this murmur is looked U.QQ.!L:J,S reasonably definite eVIdence of· mitral involvement. Months or years after the appearance of the first signs of mitral damagea-rhird m1.i~lllur may become evident. Thi~is t~eJamiIiarpresystolic mllrmur.
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STANLEY GIBSON
which is rumbling in character beginning at an appreciable interval after the second sound and ending abruptly with the first heart sound. The presystolic murmur is often quite localized at or near the apex and may be missed entirely unless one listens carefully in and about the apical region. It is much better heard in the s,!!pil1e position than when the patient is sitting, and may in some instances become· audible only in the left lateral position. There are then three murmurs which may be heard at the apex due to rheumatic involvement of the mitral valve. In the milder cases only the systolic murmur may be heard. In others the mid-diastolic murmur is also heard. In still others a presystolic murmur becomes evident. At times all three murmurs may be heard at one time. In some instances the valve may apparently heal, so that the murmurs previously heard may disappear. This is particularly true in the case of the systolic and mid-diastolic murmurs although once the presystolic murmur is well heard it is usually a permanent finding. In addition to involvement of the m~y!!!ye the !l()..!'ti.c. Y;llye is also frequently invaded in the rheumatic process. The lesion at least in its early stages is chiefly that of insufficiency and is manifested by a c!ie~~.Qlic .murmur, u~~gllY blowing in charact.er, ~~.gipning with the second soun~, bestheard in the third and fourth interspaces along the ~lfsternaImargln. It is important to emphasize the fact that this murmur in children should be sought along the left sternal margin and not over the aortic area. The aortic murmur is much better heard with the Bowles type of stethoscope than with the bell, and in my own experience the naked ear applied to the chest is the best means of all. In early cases the murmur is very short, soft and localized and will be missed unless a careful examination is made. It is distinguished from the diastolic murmurs of mitral disease by its location and by the fact that it begins with or immediately after the second heart sound. Stenosis also occurs in rheumatic involvement of the aortic valve though it is seldom clinically evident in children. Its presence is indicated by a harsh, rough systolic murmur which is heard best in the first and second right interspaces near the sternal margin. Involvement of the tricuspid valve is not unusual, but it is usually of lesser extent than the accompanying mitral involvement and the findings are so nearly identical with those arising at the mitral valve that diagnosis is seldom possible. The pulmonary valve may occasionally show slight involvement at postmortem examination, but clinical evidence is practically never present during life. Finally, attention should be called to the pericardial friction rub which occurs in acute pericarditis. Typically it is a to-and-fro sound which is harsh, rasping or leathery in character, often louder in systole than in diastole. The sound may be heard over the entire precordiuIll, or even beyond, and may sometimes be heard in the back. It may completely obscure any cardiac murmurs which may be present. On
SIGNIFICANCE OF HEART MURMURS IN CHILDREN
43
the other hand, the friction rub may be very localized, llIay occur in only one phase of the cardiac cycle, and may be so soft that it is difficult to differentiate from a heart murmur. In doubtful cases repeated examinations may be necessary. The friction rub is transient, and changes in quality and location from day to day. Heart murmurs remain relatively unchanged over longer periods of time. Summary and Differential Diagnosis.-Having outlined the characteristics of the murmurs which are encountered in congenital heart disease and in rheumatic heart disease, let us attempt a brief summary, and consider the differential diagnosis. IE-S()~s:en~t~llle!!r"tAiseas~ _tQe murmur of interventricular septal defect is systolic in time, maxImumin -the-thIrd and fourth left interspaces I~ediar to the apex; th~! Dropen foramen ovale (when it is present) iuystalic...jorime, ~est hear(rIn- the-second and third left ip.terspaces; the murmur of aortic stenosis"issystor!~JQ--tiijie- arid-maximum in the-second rIght intersp·~ice; -rFiat-of.21!Jl1)911i£stenosis ()ccurs in systole with its greatest intensIty in the second left interspace; the murmur of a patent ductus arterIOSUS is continuous and is loudest in the first and second left interspaces. In rheumatic heart disease, systolic. and diastolic rnurmurs are heard at -the apex -when die mitral valve is "involved, and a diastolic murmur iSliearanear the- sternum in the third and fourth'lnterspaces in ins~lenc:y"or.ihe aortic valve. - . It will thus be noted that the murmurs of congenital heart disease are loudest over the body of the heart or at the base rather than at the apex. It will also be noted that with the single exception of the continuous murmur of patent ductus arteriosus those mentioned are all systolic in time. In contrast, the one important systolic murmur in rheumatic heart disease in children is maximum at the apex. Diastolic murmurs may be heard at the apex in mitral involvement, and along the left sternal margin in the third and fourth interspaces in aortic involvement. In sh()rt, a systolic murmur best heard above. the apex is Eresumptive evidence otcongenital heart disease, while a diastOllcmurmur either at the apex or above it (save for the "cII;istollc phaseth-e murmur of patent ductus arteriosus) is suggestive of rheumatic involvement in the heart. -_."" ..... In typical cases the differential diagnosis can usually be made by a study of the murmurs alone. It should not be forgotten, however, that both congenital and rheumatic heart disease may exist in the same individual. This may confuse the picture. Moreover, as was emphasized in the beginning, other means of diagnosis must not be neglected. The patient's age and history are important. An organic murmur heard during the first year of life is practically always due to a congenital defect, aQgyp to the age ()f }year~ [heumatit:: invasion of the heart is infreqtlent. The history or the presence of joint pains, rheumatic-· nodules, chorea or of annular erythema suggests rheumatic in-
ot
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STANLEY GIBSON
fection, and would naturally in the case of doubtful physical signs in the heart influence one in favor of a rheumatic cardiac involvement. Finally, the entire patient, not merely the heart, should be examined, and the use of x-ray, the electrocardiogram and other laboratory means should be employed as necessary to complete the diagnostic study.