THE significance of systolic murmurs*

By D. M. LYON, M.D.

Introduction.?Investigation of the heart by means of really began with the introduction of the mediate method of approach by Laennec,43 though even before that time it had been known that unusual sounds might be produced by the diseased heart. Allen Burns,9 who was lecturer on Botany in Glasgow, described such sounds in a case where the mitral valve was indurated and the pericardium was inflamed. During life, examination of this patient revealed a jarring sensation on palpation and a hissing noise as of several currents meeting, the sound resembling that heard in a varicose aneurysm. He noted that Dr Rutherford in his Clinical Observations had described a similar condition and Suggested that it was something of this kind which was described as audible palpitation in some diseases of the heart. " Laennec tells how within the past few years, some physicians have attempted to gain further information about the heart by application of the ear to the cardiac region, and says that Bayle, a fellow student, was the first to examine the in this way. Then he describes how in 1816 he had occasion to examine a very fat young woman with general symptoms of . was impossible and immediate auscultation inadmissible because of the sex and age of the patient, so he recalled the simple acoustic feet that the scratch of a pin at one end of a piece of wood could be clearly heard by the ear applied to the other. No suitable wood being at hand, he rolled a quire of paper into a cylinder, placed it on the chest and listened, and was surprised and pleased to hear the sounds of the heart better than ever before. Thus began a new era in physical examina- " tion of the heart. Soon it was that a bellows " recognised sound was associated with the presence of organic valvular disease, but even Laennec knew that a murmur often occurred when the heart was perfectly healthy as, for example, in hysteria. From that time onwards systolic murmurs have been a constant source of difficulty. Byrom Bramwell s 5 " statement that physicians do not agree as to what indications * A Honyman Gillespie Lecture given in the Royal Infirmary of Edinburgh on 24th July 1941. D. M. Lyon point to endocarditis in the living," though written in 1884, might well be repeated to-day. Throughout the whole of the nineteenth century medical men playing for safety tended to regard the presence of a murmur as definite evidence of 24 organic disease, although authorities such as Gairdner (1861) pointed out how harmless many murmurs are. This led to much unnecessary invalidism, and brought no credit to the profession. Sir James Mackenzie has told how unsatisfactory were the orthodox views when he removed to London at the beginning of this century, and he did much to influence medical opinion. By this time the pendulum had swung too far in the opposite direction and the advice to throw away the and trust to early symptoms was frequently quoted.406,25 Many physicians were now prepared to agree that a systolic murmur of itself was of no importance,32'40 and that attention should rather be focussed on the presence or absence of other .63 It has even been suggested that organic disease of the mitral valve should never be diagnosed unless a diastolic murmur is also present.81 This is carrying the matter too far, for everyone who has successfully restored compensation in a first break-down must admit that a systolic murmur may be the only remaining evidence of cardiac disease. The true position is that, while some systolic murmurs un- doubtedly indicate the presence of an organic lesion, many are perfectly innocent.29& Though the characters of typical organic murmurs are well known and have been fully described, many variations are possible and almost every feature can be imitated by one or other of the functional murmurs. To neglect a murmur because there is no definite history of rheumatic fever or other evidence of organic disease would be manifestly unsound. On the other hand, the advice that all systolic murmurs should be regarded as organic until 8 otherwise explained can only lead to injustice and discredit unless a real attempt is made to settle the question. It has been cynically remarked that we wait to diagnose the murmur until it is no longer there to diagnose.1 The Medical Research Committee report of 1917 states that " in everyday practice an attempt to differentiate simple from serious murmurs is generally not undertaken, and if it is the 52 results are unreliable." Yet it would seem obvious that the diagnosis should be made as accurately as the subject now 590 The Significance of Systolic Murmurs permits.8 Doctors who deal mostly with the sick, and students whose experience is confined to hospital practice, will be chiefly concerned with the murmurs of definite organic disease, but those who examine apparently normal individuals, candi- dates for the services and proposers for life insurance will find many murmurs of an innocent nature. A correct decision is oi first grade importance both to the individual and to others who are interested in his well-being. All systolic murmurs, therefore, require careful study to discover whether they are important or not. Function murmurs are very frequent, and it has been sagely observed that common conditions are more likely to occur than uncommon ones.3?

The Production of Murmurs

The normal first sound of the heart is a composite noise caused by the sudden increase of pressure throwing into vibration the auriculo-ventricular valves, the chordae tendineae and the walls of the ventricles. The muscular contraction itself may contribute a little.82 Murmurs are new sounds produced by other mechanisms, but al.so subject to ordinary physical laws.11 Corrigan in 1828-913 was the first to offer a correct explanation for the appearance of a murmur. He attached a piece of intestine or a length of artery to a tap and found that when the tube was constricted a and a thrill were produced beyond the narrowing if the rate of flow was great enough. Elliotson 18 pointed out that Nature has given an exact proportion between the size of the openings and that of the cavities so that the blood passes easily and noiselessly." In tubes of uniform bore the movement of fluid is linear, the outer layer wets the walls and remains adherent, while the axial stream moves fastest, and between these extremes the fluid slides forwards like a series of concentric cylinders slipping over each other. Such straight-line move- ment is silent, but under certain circumstances the flow becomes turbulent or eddying, and the vibrations set up in it are conveyed to the surrounding structures and so give rise to new sounds. Turbulent flow will be induced in a simple tube if a critical velocity is exceeded, and the rate at which this occurs depends on the viscosity of the fluid. Eddy currents are set up more readily when the blood is thin, and this accounts for some of the murmurs in anaemia. 59i D. M. Lyon

Turbulence may also be produced by conditions which lead to the formation of a fluid vein in the stream, a phenomenon described by Savart (1833).72 The requirements are that the blood flows through a narrow area into a wider lumen beyond. The simplest case is where a systolic murmur is produced by pressure of a finger or the stethoscope on an artery, as was demonstrated by Corrigan. Other examples are a stenosed aortic or pulmonary orifice with a normal vessel beyond, or a normal valve opening into a distended vessel. A similar state of affairs exists in the case of an aortic aneurysm. At the auriculo-ventricular valves the necessary conditions are observed when the cusps fail to close the opening completely during systole. The essentials for the production of a sonorous fluid vein are that the stream at sufficient velocity should emerge from a narrow orifice into a wider chamber. Chauveau,11 who investigated the question experimentally, found that the murmur was produced just beyond the narrowing, and was well conducted in the direction of the stream, but to a much less extent above the obstruction. He showed that there must be at least a certain difference in cross section between the two parts of the stream and that a minimum of force was necessary for the production of a murmur. If the stenosed orifice were very small the stream might be too slight to give much intensity to the murmur. Reid,626 experimenting with tubes of rubber and brass, confirmed these facts, and suggested another possible cause for turbulent flow. He found that, if a smaller tube sprang from a larger cavity in such a way as to offer a sharp lip or a cul-de-sac to the current, a localised murmur was produced best heard on the proximal side of the junction. Several experimenters have definitely shown that, because of the wetting of the surface, no murmur was produced by mere roughness of the walls unless it was sufficient to narrow the lumen appreciably.6''81 Thickening or calcification of a cusp which caused it to project as the blood flowed over it would set up waves like the lip of a whistle, but the question of narrowing of the channel also arises in this case. A valve cusp which is too short to close the auriculo-ventricular orifice may become suddenly taut and vibrate like the plucked string 80 of a musical instrument. Thayer and MacCallum found that tearing the chordae of a mitral cusp gave rise to a soft systolic murmur over the left ventricle and a very loud murmur and a thrill over the left auricle as Chauveau's theory demands. 592 The Significance of Systolic Murmurs

They also found that very slight pressure over the conus or the pulmonary artery was sufficient to produce a murmur. All these conditions are associated with the development of 16 eddy motion in the current. Davison injected fluid into a length of intestine or aorta by means of a syringe and nozzle, and found that a murmur occurred if the entering stream impinged with some force against the wall, although no sound was produced if the axis of the stream was the same as that of the tube. This condition may occur in the case of the pulmonary artery which bends a short distance above the valve. Many theories have been put forward to explain intra- cardiac murmurs. Friction of the particles of the blood against '7 each other or against the walls was an early suggestion.19'34' Spasm of muscle, irregular contraction, increased tone, loose atonic walls, paralysis of papillaries have all been considered but are nothing more than wild guesses. Vibrations originating in the turbulent fluid are picked up by neighbouring tissues, cardiac muscle and vessel walls and are transmitted to the chest wall, and these structures tend to modify the sounds. Heart muscle lowers the pitch as also does bone in proportion to its porosity ; air-containing lung conducts sound poorly but slightly raises the pitch.65 When the vibrations reach the sternum and ribs, these act to some extent as a sounding board.706 Sewall has shown that the sounds may be modified by the amount of pressure exerted by the stethoscope.703 Firm pressure intensifies sounds directly transmitted to the surface, while it damps down the sympathetic vibrations due to the sounding-board effect of the chest wall. By this means it should be possible to determine more accurately the exact position of the maximum and the source of the murmur. The presence of a gassy stomach or a lung cavity near the heart may increase a murmur by resonance or may give it a metallic quality.49 There are certain difficulties in connection with the ordinary mitral systolic murmur which are not easy to explain. Accord- ing to theory it ought to be loudest in the direction of the blood flow, that is in the left auricle, and fainter on the proximal side?the left ventricle. A murmur believed to originate at the mitral has been described in the third left intercostal space over the tip of the left auricle but the usual site of the maximum is the apex.3,70a Why this should be so is not known, but it vol. xlviii. no. 9 593 2 T D. M. Lyon has been suggested that the anterior papillary muscle accounts for this special line of conduction.71 Once the mitral systolic murmur has reached the surface at the apex it might be expected to be carried equally in all directions rather than chiefly towards the axilla. In trying to estimate the meaning of a murmur it is important to remember that the area over which it is audible depends on its intensity or loudness. Faint sounds are very localised, loud murmurs may be carried to a considerable distance. Loudness depends partly on the character and degree of the lesion and partly on the rate of the blood flow. In the case of a stenotic lesion the intensity of the murmur varies inversely with the size of the orifice up to a point where the stream becomes inconsiderable. At the auriculo-ventricular valves it is possible that a small leak may be more noisy than a large one. The other factor, velocity of blood flow, depends on the rate and the strength of the muscular contraction. In general, rapid or vigorous systole increases the intensity of a murmur, while it becomes less or may even disappear when the rate becomes slow or the muscular contractions feeble.

Points to be Observed in Examining a Murmur When a murmur is discovered attention should be paid to its place in the cardiac cycle (timing or rhythm:) and its relation to the . The murmur may accompany the sound or obliterate it. It may begin synchronously or commence a little later so that the sound dissolves into the murmur. The diiration may vary considerably ; some are very short, others extend to fill up most of the first pause. Most systolic murmurs are diminuendo, fading away towards their end ; one at least has a crescendo beginning. One of the most important observations is the site of maximum audibility, since this has been well established for all the regular valvular murmurs. From this point the murmur fades in all directions though it may do so more rapidly in one than another. The area of audibility is really a function of the loudness of the murmur, faint sounds being very limited while loud sounds may still be heard at a considerable distance from the maximum point. The direction of propagation, conduction or transmission is important in endeavouring to decide the origin of the murmur. 45a Levine has proposed a scale for recording the intensity of a 594 The Significance of Systolic Murmurs

murmur, and the plan is very useful, though the estimation of loudness is entirely a personal factor. He employs six grades? i. faint or very slight, 2. slight, 3. moderate, 4. loud, 5. very loud, and 6. loudest possible (to be heard without a stethoscope). The loudness is not necessarily proportionate to the severity of the lesion. The acoustic character or quality of a murmur can usually be classified as soft, harsh or musical, though a large number of unnecessary adjectives have been employed to amplify the description?soft murmurs may be blowing, , whist- ling, whizzing, cooing, mewing, puling, squeaking or rumbling, while coarse rough murmurs may be rasping, grating, filing, scraping, scratching, sawing or rubbing. The pitch or timbre may be low, medium or high. Some murmurs appear to be more superficial than others. Some are constant under all circumstances, others are very evanescent, coming and going spontaneously or under special conditions. Respiratory move- ments greatly affect some murmurs, others remain constant throughout the whole respiratory cycle. The posture of the patient often determines whether a murmur will be audible or not, and a change of position may intensify or decrease a murmur already heard.29a,Ga Most murmurs are influenced by the rate of the heart. Exercise, excitement and fever may cause augmentation, while many murmurs become faint or even disappear when the heart becomes quiet after a period of rest. It was pointed out that the chest wall conducts murmurs by acting like a sounding board. Many murmurs are modified by the pressure employed in holding the bell of the stethoscope on the chest wall.'0? Firm pressure, especially over the con- duction areas, may damp out the murmur or may change its quality. Most authorities emphasise the difficulty of fully evaluating a systolic murmur, and counsel that careful attention should be paid to the presence or absence of other features, such as amzinia, the quality and rate of the , the position and character of the apex beat, evidence of hypertrophy or dilatation, the state of the second pulmonary sound which may be accentuated, diminished or absent, and whether there is a thrill or not. A history of rheumatic fever will be suggestive of organic disease, though functional murmurs may be present in a heart which has escaped the ravages of the infection. The exercise tolerance test has its uses and limitations. Where 595 D. M. Lyon

facilities exist radiological determination of the size of the heart (orthodiagraphy) may be helpful. If any doubt exists as to the true significance of a systolic murmur, repeated examinations should be carried out on different days, in various postures, after exercise and after rest. The features of a murmur are not all of equal value to the diagnostician. The actual qualities of a murmur are perhaps the least important, for under different circumstances the same murmur may be harsh and grating or soft and blowing. The most important points are the site of the maximum, the line of propagation and the timing. There are really no fixed rules for differentiating organic from functional murmurs. Each murmur must be carefully studied and considered on its merits. The final judgment must be based on a consideration of all the facts presented. Organic murmurs are usually found in the valvular areas with characteristic propagation, and are more constant than functional ones. The presence of a murmur is more significant if the heart is slow. Musical and scratching sounds are rarely functional. The presence of a thrill, an accentuated second sound or cardiac enlargement are helpful, and a history of rheumatic fever is suggestive.

Mitral Systolic in Organic Disease

The murmur of organic mitral disease was recognised early 34 in the history of auscultation. Hope gave an account of it in 1825, and Elliotson, who was one of the pioneers in the investigation of heart disease, in 1833.18 Most practitioners probably regard mitral incompetence as the commonest of valvular lesions, yet some authoritie-s insist that simple organic disease of the mitral valve is very infrequent. The truth probably lies somewhere between these extreme points of view. Accounts of the murmur vary considerably, and no doubt a wide range of variation is possible according to whether the lesion is severe or slight and the patient is strong or debilitated. Time.?The typical murmur is exactly systolic (holosystolic) in time, masking the first sound in whole or in part, yet some admit that it may follow the first sound without replacing it. It is always diminuendo in character, fading away during the first pause. 596 The Significance of Systolic Murmurs

Site.?Most authorities state that the point of maximum intensity is exactly at the apex, though some prefer near the apex or a little above or inside it. Propagation.?The area over which the murmur is audible depends upon its intensity. When loud it may be widely heard over the whole precordium, fading as the distance from the apex increases. Characteristically it is best conducted towards the left, and it may still be heard in the axilla or even at the angle of the left scapula. The intensity varies greatly from case to case ; some are loud or very loud, others extremely faint and distant. The louder the murmur the more likely is it to be organic, yet faint murmurs are not always functional, and a very loud murmur may be present when there is very little regurgitation. Character.?The quality of an organic mitral may range from a gentle blowing to a harsh rasp or it may be whistling or musical. It is usual to regard as organic those of rougher character, though this is not invariable. Pitch.-?Usually the pitch is moderately high, though shrill and low-pitched murmurs also occur. The duration may be long or short, probably the longer forms are more common. Constancy.?An organic mitral systolic should be constantly present, or at least little affected by other factors. It may become faint or disappear if the heart becomes weak and may reappear as the strength returns. Posture.?The murmur should be heard when the patient is in any position. Usually it is louder when he is recumbent and may be increased when he rolls towards the left and it may become harsher or lower in pitch in these circumstances. Sometimes it is less obvious or even absent when the patient is erect. Respiration.?The respiratory movements should have very 26 little effect on an organic mitral systolic, though Gee suggests that it may weaken or become inaudible during inspiration. Cardiac Rate.?Emotion, physical exertion or anything which increases the pulse rate should augment the murmur. Some murmurs are only audible when the rate is rapid and disappear as the heart slows down. Pressure.?When the stethoscope is pressed firmly over the apex the murmur may be more clearly heard ; similar pressure in the transmission area often makes the murmur much fainter.

VOL. XLVIII. NO. 9 597 2 T 2 D. M. Lyon

Almost every feature which characterises an organic mitral systolic may occur with murmurs of functional origin. It is therefore advised that a diagnosis of organic disease should not be made unless there is confirmatory evidence. Enlarge- ment of the left ventricle as indicated by percussion and by the position of the apex beat is an important sign. Where organic incompetence of the mitral valve is present, the second pulmonary sound is usually ringing and accentuated or reduplicated, while the second aortic may be relatively weak. Due weight must be given to a history of rheumatic infection, though a person who has had rheumatic fever is just as liable to show a functional murmur as any normal is. The presence of dyspnoea, oedema or other signs of heart failure increase the probability of the murmur being organic in origin.

Mitral Dilatation

That not all murmurs were associated with organic disease was known to the pioneers of auscultation, yet the definite association of a systolic bruit with dilatation of the mitral valve has been credited to McDowel.47 Mitral dilatation is very common and may arise in many different circumstances. It may occur from temporary or permanent weakness of the left ventricle or may be secondary to aortic disease or the hypertrophy of hypertension. Con- sidering these various conditions, it is not surprising that the characters of dilatation murmurs should vary considerably. The weak muscle of a failing ventricle should give a different murmur from that of a hypertrophied heart. Time.?The fainter murmurs are not holosystolic but com- mence after the beginning of the first sound which may be little changed. Site.?Since the murmur of dilatation originates at the valve it might be expected to be maximum at the same point as an organic murmur, yet several authors suggest that its intensity is greatest not at the exact apex but a little to the right or the left of it. Propagation.-?The murmurs of dilatation are usually distinctly limited in their area of audibility, but this is entirely a question of their intensity and when conducted they follow the same course as the organic murmur. The intensity varies greatly in different cases. Most of the 598 The Significance of Systolic Murmurs

murmurs are relatively faint and certainly less intense than the average organic one, but if there is a strongly acting heart or if the rate is increased by fever, excitement or exercise, the murmur may be as loud. Quality.?A murmur due to dilatation is commonly softer and more blowing than the average organic one. Constancy.?Some dilatation murmurs are very variable, being present at one time and not at another. The other features are similar to those of a rather faint organic murmur. More or less enlargement is commonly present, though dilatation may occur without a murmur and a mitral murmur may appear without recognisable dilatation. The second pulmonary sound may or may not be accentuated according to the vigour of the heart.

The Mitral Systolic of Fever

The presence of a bellows sound in rheumatic fever was recognised by Latham44 in 1826, and Elliotson18 in 1833 pointed out that a systolic murmur in fever was not necessarily of organic origin. The heart sounds during a fever may be clearer and sharper than in health, and often there is merely a fiuffiness or impurity of the first sound. The occurrence of a definite mitral systolic in the early stages of rheumatic fever does not always mean that the valve has been attacked. Usually, as in the case of other febrile conditions, it results from dilatation of the orifice due to a weakened muscle, and it should have the same charac- ters as the murmur just described. It is sometimes stated that the louder the murmur the more likely is it to be organic, but little importance need be attached to this for some loud murmurs occurring in fever are apparently quite innocent.

Tricuspid Systolics

Organic disease of the tricuspid valve is exceedingly rare, and usually only occurs if there is also endocarditis of the mitral. Tricuspid systolics, therefore, are almost invariably due to relative insufficiency. The safety-valve action of the tricuspid was first pointed out by King (1837),42 who remarked that this valve was naturally weak and imperfect, and readily dilated as the right ventricle became distended. Mackenzie 50 observed that the murmur may appear with barely any dilatation 599 D. M. Lyon at all. It often occurs temporarily as the result of strenuous exertion but quickly vanishes. Money 53 has stated that it is commonly found during pregnancy. A systolic murmur in this region also occurs secondarily to failure of the mitral valve and to conditions which hamper the pulmonary circulation. Time.?The tricuspid systolic murmur accompanies the whole or the later part of the first sound. Site and Propagation.?It is best heard over the lower part of the sternum and the immediately adjacent fourth and fifth interspaces, especially the left. The murmur is not specially conducted in any direction. It seldom reaches the base of the heart but may be heard as far as the apex and if very loud may be made out under the right nipple and at the angle of the right scapula. Character.?A tricuspid systolic is soft and blowing or whiffing. More rarely it is rough or harsh and this quality suggests the presence of chronic endocarditis. The pitch is relatively high, a feature that may serve to distinguish it from a coincident mitral systolic which is usually of lower pitch. The tricuspid bruit is almost always faint and delicate ; indeed, considerable dilatation may exist without any murmur being audible. It is rather prolonged, diminuendo in character, more superficial than a mitral murmur and for the most part very fugitive. Tricuspid systolics are much more evident when the patient is recumbent, and may disappear when he is erect. Respiratory movements readily influence the murmurs which tend to be less evident during expiration. Pressure by the stethoscope does not cause the murmur to vary. The second pulmonary sound may be increased or diminished according to circum- stances. In cases of temporary dilatation nothing further may be noted, but when the dilatation is due to right heart failure the cardiac dulness is increased, the jugular veins are engorged and pulsating, the liver is enlarged and there may be , ascites and general oedema.

Aortic Systolics True stenosis is the least common cause of a systolic murmur in the aortic area. Mere roughening of the valve is considered insufficient to produce a murmur, but, if a cusp is thickened or calcified and projects into the blood stream during systole, turbulent flow will be set up. In other cases the valve remains 600 The Significance of Systolic Murmurs normal but the proximal part of the aorta becomes dilated from weakening by syphilis or atheroma. Time.?The murmur of is holosystolic, replacing the first sound entirely. Site.?Its maximum is at the aortic area in the second right intercostal space close to the sternum. The propagatioii is characteristically up towards the inner end of the right clavicle and the carotids. The murmur may be audible over the whole precordium and is sometimes well heard at the apex. If very loud it may be noted near the third and fourth vertebral spines and in extreme cases may even be heard at some distance from the chest. Character.?-The stenotic murmur is harsh and rasping, occasionally whistling or musical. Those due to arteriosclerosis of the valve or aorta are usually less rough and are more blowing in quality. The pitch is rather low and the murmur is prolonged. Intensity.?The murmur arising from stenosis is loud, while that due to other causes is less intense and rarely so striking. Murmurs associated with organic disease in this region are remarkably constant, being little or not at all influenced by posture or respiration. Increased physical activity will tend to bring out the murmur more clearly. Stethoscope pressure over the aortic area does not modify the sound, but an aortic murmur conducted to the apex should disappear from that region under firm pressure. The character of the second aortic sound is important in distinguishing stenosis from other lesions. When the valve is narrowed, the second sound is very greatly diminished or replaced by a long diastolic murmur, but where the murmur is due to dilatation of the aorta, it is ringing and accentuated. Where a stenotic murmur is very loud, a definite thrill can be felt in the same area. It is usually absent in non-stenotic cases.

Great hypertrophy of the left ventricle and a heaving apex beat displaced down and out are characteristic of aortic stenosis. These features are less marked in other cases. The pulse of pure aortic stenosis is small, hard and flat-topped (plateau type), and if aortic incompetence is also present the systolic blood pressure is lower and the diastolic higher than might be expected. 601 D. M. Lyon

Congenital Heart Lesions are not at all common. Quite a proportion of them are of a minor nature and not severe enough to show the characteristic signs, cyanosis, clubbing and dyspnoea. It is, therefore, necessary that the possibility of such a lesion be kept in mind when an unusual bruit is encountered. The murmurs associated with them are usually systolic, at least in part. Except in the case of pulmonary stenosis, the murmurs appear over the body of the heart and not in the ordinary valve areas. Usually they are localised and have not the characteristic distribution of valvular bruits. The heart sounds may be normal even when a serious defect is present.81 In many cases more than one type of deformity exists in the same patient and the exact nature of the lesion may be difficult to classify even with the help of X-rays.15

Pulmonary Stenosis

Organic disease of the pulmonary valve is very rare and when present is almost invariably due to a congenital lesion. The narrowing may be in the conus arteriosus, in the pulmonary artery or at the valve. It is often accompanied by such abnormalities as a , a large foramen ovale, or a fault in the inter-ventricular septum. The murmur of pulmonary stenosis is like the corresponding aortic one but in a different area. It is strictly systolic, masking the first sound, with its maximum in the second left inter- costal space close to the sternal border or sometimes in the third. Propagation.?The characteristic spread is up and out towards the clavicle or left shoulder but not to the carotid. It may be heard all over the precordium even to the apex and sometimes in the back. If fainter, the area of audibility is much restricted. Characters.?The murmur is a harsh unmusical blowing as a rule, but may be soft. It is usually loud and gives the impression of being rather superficial. Characteristically it is very constant, though it may be slightly diminished by a forced expiration. Posture should have little effect, and if a pulmonary systolic is not loud when the patient is erect, it should be regarded as physiological. The second pulmonary sound is usually diminished or absent or may be impure. There should be signs of right-sided hypertrophy with a 602 The Significance of Systolic Murmurs prominent conus arteriosus, but the pulse should show no change. Cyanosis may be permanent, transient or absent, and clubbing develops later. Subaortic Stenosis will give the same murmur as aortic stenosis but the second sound is not so much affected.59 A patent inter-ventricular septum is the commonest of congenital lesions but it is not always recognised during life since it causes little disability, and, if the opening is large, no murmur is produced. Roger's characteristic murmur begins early in systole and may be confined to it or may extend over diastole, obscuring the second sound. This continuous bruit with rhythmic accentuation during systole has been likened to the whirring of a knife-grinder's wheel intensified by the treadle. Its point of maximum intensity is at the fourth left costal cartilage or from the third to the fifth close to the sternum. Sometimes it is soft, blowing or rushing, at other times harsh, grating, rasping or purring. The intensity of the murmur varies inversely with the size of the opening. The murmur is of high pitch and is usually prolonged. It is very constant, not varying with posture or respiration. A thrill is frequently found and is often very intense. There may or may not be evidence of cardiac enlargement. Undue patency of the foramen ovale is relatively frequent. If the opening is very small or very large, it may give rise to no murmur or other physical sign. When present, the murmur is to be heard in the second, third and fourth left intercostal spaces close to the sternum. It is not carried in any special direction, but, if loud, may be heard all over the precordium and even at the back. In time it is late diastolic or presystolic and it may extend into systole. It is usually harsh or rasping in quality though at times soft and blowing. The intensity varies greatly, some being loud, others faint. The murmur may change with posture, and at different examinations, and often there is no bruit until the heart becomes more active. A thrill is not common, but may occur. Cyanosis is usually absent, though it may appear from time to time, asr for example, in the course of a fever. A patent ductus arteriosus seldom occurs alone, being usually accompanied by a fault in the inter-ventricular septum. Owing to the difference of pressure between the two vessels, the flow through the duct occurs from aorta to pulmonary 603 D. M. Lyon artery. If the passage is very wide, a more serious condition, there may be no murmur. Gibson's pathognomonic murmur may be continuous almost throughout the whole cardiac cycle.27 Beginning shortly after the first sound it fills the short pause, obscures the second sound and comes to an end just before the first sound. It waxes and wanes so that the cardiac sounds appear as accentua- tions of the bruit. It has been likened to the humming of a top, the noise of machinery, of a mill-wheel or of churning ; also to the rumbling of a train in a tunnel or the rolling of thunder, and it has a considerable resemblance to the murmur of an arterio-venous aneurysm. In young children a murmur is not always present or there may be merely a systolic blow, the diastolic element being added about the age of five.57 The murmur is best heard in the first, second and third left interspaces about two inches from the sternal border, a little farther out than a pulmonary systolic. Though loud, it is rather local, diminishing rapidly in all directions. It is not usually carried to the apex, axilla or carotids, though sometimes it may be heard in the back opposite the third and fourth dorsal spines. In character the bruit is harsh, rasping, roaring, rolling, rumbling or rushing. Its pitch is low, and it is mostly of considerable intensity. Deep inspiration may intensify the murmur, which may also be markedly influenced by posture, often when the subject is recumbent only a systolic element being heard. If the murmur is loud, a thrill can usually be felt during the same part of the cardiac cycle as the murmur. The second pulmonary sound is sharp, ringing and greatly accentuated. An area of extended dullness may be noted in the second and third left spaces and there is usually some enlargement of the right ventricle. The 4C& diastolic blood pressure may be unduly low. Lewis says that if there is neither cyanosis nor enlargement, and if the exercise tolerance is satisfactory, the lesion may be safely disregarded. Coarctation of the aorta, a narrowing of the main vessel between the origin of the left subclavian and the opening of the ductus arteriosus, is a lesion which seriously handicaps the circulation. In a well-marked case the external appear- ances are sufficiently characteristic to warrant a diagnosis. The superficial vessels of the upper part of the body are greatly 604 The Significance of Systolic Murmurs

distended and pulsate. The blood pressure is high in the arms, and low in the legs. The left ventricle is hypertrophied and the first part of the aorta may be dilated. The murmur of coarctation is systolic or post-systolic. It is best heard to the left of the sternum between clavicle and third rib, but may extend over the whole precordium, to the neck and down the posterior aorta. In character it is rough and hissing, loud and of long duration. A thrill is common. The second aortic sound may be clear and ringing, or may be replaced by a diastolic murmur. The bruit is unlikely to give rise to any diagnostic difficulty, since few who are subject to coarctation reach adult life.

Functional Murmurs

The terms functional, physiological, accidental, innocent, non-organic and non-pathological have all been used to describe the many harmless murmurs that may be heard over the precordium. All these names are subject to criticism, and it " is perhaps best to call them functional," for this term is well " understood as the opposite of organic," and it may be used for all murmurs not due to structural changes in the valves. That murmurs may occur in the absence of organic disease has been known since the time of Laennec.13'84 They may appear in a great variety of physical disorders, and also in subjects who are in normal health and especially in the young. Indeed, it has been suggested that it is surprising that they are not more commonly found than they are. Such murmurs may arise in many ways and not all are associated with the valves. This being so, there is little to be gained by generalising about functional murmurs as a group. Certainly they are invariably systolic in time?if the rare pulmonary diastolic due to obstruction of the circulation in the lungs be excluded. In general they are feeble. Levine,45^ says that functionals are usually faint (grade i), while slight murmurs (grade ii) are less frequent, and moderately intense ones (grade iii) are relatively rare. This explains why they are circumscribed and poorly conducted. They are mostly soft and blowing, of short duration, accompanying rather than replacing the first sound, are very variable and readily influenced by posture, respiration, and cardiac rate. There are exceptions, however, and many functionals may closely imitate bruits of organic origin. 605 D. M. Lyon

There are no very comprehensive estimations of the incidence of functional murmurs ; reports seem to be entirely coloured by the experience of the writers. A high proportion may be found in normal individuals after strenuous exercise (football,78 20 Marathon race83,84). Fahr reports that 3-2 per cent, of all recruits examined showed functional murmurs. In children 76 very high figures have been recorded. Siemsen gives 79 9 per cent, at rest and 46 per cent, after exercise, and Thayer 56 per cent, in the first decade and 19 per cent, in the second. The Cardio - Respiratory Murmur is probably the commonest of all functional murmurs.60 It is really a rhythmic exaggeration of the breath sound, and is often classified as a form of cog-wheel respiration (a term which also includes the jerky breathing of the nervous individual). Two varieties of cardio-respiratory bruit have been described. One is heard over substance lesions of the lung, such as consolidation, atelectasis or cavity, usually at or near the anterior border of the upper lobes. In the earliest cases described,64 adhesions between the lung margin and the pericardium were found post mortem, but these are not essential. The other and more common form occurs in healthy persons. Time.?The cardio-respiratory murmur does not replace the first sound but begins rather late in the cardiac cycle, and always ends before the second sound. Site.?The murmur is audible about the apex, and along the left border of the heart, more rarely over the right border. Its maximum is not necessarily at the exact apex, but may be somewhat farther to the left. It may be well heard in the axilla and even over the back. In character it is a soft, short, sharp whiff beginning and ending abruptly, rather like the puff of an engine. It has also been described as blowing, sipping or swishing and is never harsh or rough. The pitch is rather high, like that of ordinary vesicular breathing. The murmur varies greatly in intensity ; usually it is faint, though rarely it may be loud enough to be heard without a stethoscope.33 It has a definitely superficial quality. The most characteristic feature is the way the murmur varies throughout the respiratory cycle. It is loudest or may be heard only during inspiration. In about half the cases, it is present during both inspiration and expiration, but 606 The Significance of Systolic Murmurs dwindles during expiration and usually disappears towards the end. If the breathing is arrested at full inspiration or full expiration or indeed at any point, the murmur may cease, though sometimes it continues to be audible. Deep breathing tends to exaggerate it. The posture of the patient has often a profound effect on the murmur, though there is no definite rule.31 Sometimes it is only heard when the patient is erect or only when recumbent, and at other times may be audible in both positions. Local presstire with the stethoscope may vary the intensity of the murmur. Exercise usually makes it more evident. The cardio-respiratory murmur is extremely variable, being clearly heard at one examination and absent at another. In the vast majority of cases the murmur is of no importance ; if lung disease is present other signs will draw attention to it.

Haemic Murmurs

The occurrence of systolic murmurs in those who are severely anaemic has long been recognised. Marshall Hall 30 in 1832 reported his investigations on blood-letting?" the most powerful of our remedies." He found that when a considerable quantity of blood had been removed the pulse quickened, the heart and the great vessels beat forcibly, and " on auscultation there was a peculiar noise resembling that " " of a saw or file which might lead to the erroneous conclusion that there was disease of the heart or valves." The innocent character of the murmurs in anaemia is shown by the fact that they may gradually disappear as the blood improves. As already explained, the normal silent flow depends on the relationship between the size of the cavities and the orifices, the viscosity of the blood and its velocity. Thin blood breaks into turbulent motion more readily, and there is ample evidence that the circulation rate is considerably increased in anaemia. It is really surprising that haemic bruits are not more often encountered. They were common in chlorosis, but are much less frequent in pernicious anaemia. This difference may depend on the vigour of the heart, for in pernicious anaemia degenerative changes are common and the cardiac action is feeble. Since haemic murmurs depend on the flow of the blood, they are of valvular type. They are to be found both at the 607 D. M. Lyon

apex and the base, but, as the semilunar valves are open during systole and the auriculo-ventricular valves are shut, different mechanisms must operate at the two sites. At the base it is sufficient to postulate an increased rate of the thinner blood. The apical murmur must depend on muscular weakness and relative incompetence, since disordered movement within the ventricle itself is unlikely. Hsemic murmurs are about three times as common at the base as at the apex, and pulmonary bruits occur twice as frequently as aortic ones. Tricuspid murmurs are rarely found in such cases. Time.?All haemic murmurs are systolic in time; they seldom begin with systole but are meso-systolic and they end before the second sound. The site and propagation of the murmurs correspond with the usual valve areas. The extent to which they are conducted depends entirely on their loudness. Some are extremely localised, others are conducted far, Garrod2a says even to the back. Characters.?In quality haemic murmurs are not essentially different from the corresponding organic bruits. Usually they are soft and gentle, whiffing, blowing or rushing and short in duration. Rarely they are rough, although they may easily become harsh and loud on exertion. The pitch is usually low or medium. They are mostly faint and slight and are often difficult to detect when the heart is quiet, and they are very variable, coming and going from day to day. Posture has a greater effect on haemic murmurs than on organic ones. They become louder and are heard over a wider area when the patient is recumbent, or they may be audible only in this position. The effect of respiration is inconstant. Often the murmurs are loudest towards the end of expiration, and they may diminish or become inaudible when a deep breath is held. An increased cardiac rate due to emotion or effort augments the murmur or brings out one which was absent when the heart was calm. A haemic murmur should only be diagnosed when there are definite evidences of a severe degree of anaemia. The venous hum should be present in the external jugular in these cases, and an arterial systolic should be easily produced by pressure over the carotid or subclavian arteries.

608 The Significance of Systolic Murmurs

Systolic Murmurs associated with Overaction of the Heart

Systolic murmurs are known to occur in a great number of conditions in which the activity of the heart is increased, both in health and in disease. Severe physical effort, wrestling, a short sharp spurt, a game of football and a Marathon race may produce a high proportion of murmurs. Almost any form of nervous tension, simple excitement, fright, fear, the strain of being examined by an unknown doctor, also psycho- neurosis, hysteria and the effort syndrome may cause the appear- ance of systolic murmurs.14'5aa Bruits are common in hyperthyroidism and in fevers of all kinds, and some of these may be of the same nature. A temporary murmur has been noted as the result of raising the body temperature by means of a hot-air bath.36 These abnormal sounds may not all depend on the same mechanism, but there are certain facts which suggest that similar murmurs may occur in each of these conditions. In all this group there is apparent over- activity of the heart, with palpitation, and presumably an increased rate of blood flow. The murmur appears to be dependent on the rate of the heart and on the peculiar type of impulse associated with the tachycardia. In these conditions the apex beat is not localised but is diffuse and wave-like, having a fairly forcible , yet different from the deliberate and vigorous impulse of hypertrophy. At the same time the pulse is fast and jerky with a large wave poorly sustained, a condition which has suggested imperfectly filled 37 vessels ! A pulse rate of 120 or more is not uncommon in a healthy person excited by the examination. At this rate a murmur is present, which vanishes as the heart calms down and reappears if the rate is increased again by exercise. According to the literature, murmurs associated with tachycardia and palpitation may occur in any of the valve areas, but by far the greatest number are to be found about the apical region. Pulmonary bruits are much less frequent, while tricuspid and aortic ones are rarely mentioned. The pulmonary and aortic murmurs may depend on the production of an audible current from increased blood flow or on the unmasking of one of the other forms of functional basal murmur, and nothing further need be said of them. It is difficult to form a composite picture of the apical murmurs associated with cardiac overaction, as the descriptions vol. xlviii. no. 9 609 2 u D. M. Lyon are so varied. Some are very transient, others more persistent according to the conditions with which they are associated. A careful analysis of the literature does not show any specific differences between the murmurs of exercise, emotion or the effort syndrome. Each group may present faint, almost inaudible, bruits, or loud, harsh sounds, and the differences are probably merely a matter of degree. Allbutt describes a larval impurity or reduplication of the first sound which precedes and follows the presence of a murmur in overstrain of the heart, and others speak of an accentuated 12 snapping or ringing first sound or a blurring as the result of effort. Many overacting hearts, however, show undoubted systolic murmurs in the apical region. Time.?When faint, they do not obscure the first sound but occupy its later part and disappear in the first pause. Site.?The maximum point is usually described as being over the left ventricle a little above or internal to the apex rather than at the apex itself. Propagation.?The murmur is often remarkably local, probably because it is faint, but some can be heard in the axilla or even in the back. Characters.?Sometimes the murmur is soft and blowing like a faint organic mitral; others are harsh and rough, and such terms as whizzing, buzzing and burring have been used to describe them. Often they are faint, though others are loud enough. The pitch may be low or high. These murmurs are often very transient and sometimes disappear before the examination has been completed. Posture has an important influence on these murmurs. They are best heard when the patient is erect, and they may disappear when he is recumbent, no doubt partly due to the slowing of the circulation. Even very slight exercise, such as walking round the room, intensifies bruits due to excitement, but they readily become less as the heart calms down. Statements about the influence of respira- tion differ greatly. It produces no constant change, though sometimes the effect is considerable. Da Costa, describing the irritable heart of effort syndrome, says that the murmur disappears with deep inspiration and its place is taken by a peculiar clacking sound. The second sound is usually accen- tuated and is often reduplicated.

610 The Significance of Systolic Murmurs

Pseudo-stenosis

In cases due to excitement it is a common experience to find a definite thrill when the hand is placed over the apex. This is usually feeble and of short duration and is seldom so intense as that of mitral stenosis. Because of the tachycardia it is difficult to time the thrill accurately, but it is said to be 38 really systolic.4' The thrill is exceedingly common in normal subjects examined under nervous strain and is more frequent in thin individuals.416 Its presence, together with the snapping first sound and a systolic murmur of harsh character, gives rise to the suspicion of mitral stenosis. Many writers have 62a drawn attention to this problem.7'17' 32>68'7a6 Reid points out that the ordinary mitral systolic bruit has a slightly crescendo beginning and fades away in diminuendo fashion before the second sound, and it has been suggested that the crescendo murmur of excitement is merely an exaggeration of this.6 Accentuation of the second pulmonary sound is of little help in these cases, for it may be greatly increased by excitement. To distinguish this murmur from that of mitral stenosis the use of nitrites has been proposed.54'28 Inhalation of amyl nitrite quickens the heart, dilates the peripheral vessels and 23 is said to get rid of accidental murmurs, yet Friedlander showed that when amyl was given to ioo normal individuals, systolic murmurs were produced in 47 of them ! (47 pulmonary, 25 mitral and 7 aortic). The thrill and the crescendo quality readily disappear when the heart slows down.

The Bridge Murmur

In some cases of nervous tachycardia a systolic murmur is to be found in the fifth interspace or less often in the fourth. It is extremely localised, being heard at one spot only, and if the stethoscope is moved very slightly it vanishes. Closer observation shows that the murmur is audible only when the bell of the stethoscope rests on two ribs and so bridges a space. If it touches the space and only one rib, either that above or below, the bruit disappears. This phenomenon has also been reported by Kahn.41a 21 Flint described a metallic jingle or tinnitus which may be noted near the apex in healthy young individuals who are excited. The sound may be imitated by putting the palm 611 D. M. Lyon over the ear and percussing lightly on the back of it, or by percussing a rib near the stethoscope.26 Money,53 speaking of puerperal women, mentions a curious click which may accompany the first sound just above and to the left of the ensiform, and also a short but loud, high-pitched, superficial, friction-like systolic limited to an area the size of a shilling. It is not clear whether all these murmurs associated with overaction of the heart are of the same nature. They certainly depend on the rate of the heart, for they disappear as the tachycardia subsides. How they are produced has not been decided. That they originate at the valves is uncertain. If temporary dilatation occurs it would be much more likely at the tricuspid, but the murmur is heard rather farther out 4S'01 than this area. Some writers have thought that they could detect temporary enlargement of the heart in these 74 cases, and Schott by X-rays proved that it did occur after severe exercise. Another explanation is that the murmur depends on the apex forcibly striking the edge of a rib.21 In many cases one certainly gets the impression that it has to do with the unusual character of the cardiac impulse. The first sound over the inner part of the fifth interspace has a peculiar slapping character when the murmur is present. These peculiar sounds give rise to a good deal of worry, not so much on their own account for they are easily recognised, but lest they obscure a really significant lesion. No final opinion should be given until the pulse rate has fallen to within normal limits. In cases of excitement the circulation may be slowed by ocular pressure or by a short period of recumbency or by distracting conversation.

Pulmonary Innocent Murmurs

Balfour3 referred to the pulmonary area as "the region of cardiac romance." Organic lesions of this valve are rare, so the vast majority of murmurs in this position are functional and they are very common. They include haemic and cardio- respiratory bruits as well as others which are special to this region. It has been stated69 that pulmonary murmurs may be found in 6o per cent, of all children under the age of fourteen. They are common in adolescents with flexible chest walls, in thin-chested individuals and especially in women. Firm 612 The Significance of Systolic Murmurs

pressure by the stethoscope may readily elicit a bruit in such subjects.u5&'79 These murmurs tend to disappear as the thorax becomes fully developed.40'08 Persons in poor training lose the murmur as the physical strength improves, and temporary pulmonary bruits occurring in fever and in cardio-vascular asthenia also disappear as health returns. Functional pulmonary murmurs are also associated with traction or pressure from neighbouring organic lesions. Such murmurs have been noted in cases of pericardial effusion, aneurysm, enlarged mediastinal glands, paralysis of the respira- tory muscles, left-sided pleural adhesions or tuberculous lesions and a right-sided pleural effusion causing displacement of the mediastinum. Dilatation of the pulmonary artery from " aneurysm, or secondary to mitral stenosis, will cause a relative " narrowing and will give rise to a pulmonary systolic murmur. Many suggestions have been put forward to explain the occurrence of these murmurs. Where lesions exist in the neighbourhood of the vessel, compression of the artery or dilatation from traction or weakness of its walls would give conditions suitable for the formation of a fluid vein. The murmurs occurring in persons apparently healthy are less readily explained. Most writers postulate some alteration in the relationship of the conus and pulmonary artery to surrounding structures.6'20'39 These parts of the heart lie very superficially separated from the chest wall by a thin wedge of lung. In full expiration the cushioning action of the lung is withdrawn and the pulmonary artery beats directly against the thorax and may become temporarily deformed. 2 Allbutt suggests that in overwrought athletes and even in normals there may be a shift of the dilated pulmonary artery against the chest wall. 22 The post-mortem observations of Foxwell are of special interest. He was struck by the fact that in many cases showing a pulmonary systolic during life the conus and pulmonary artery were dilated. Normal hearts with the pericardium intact gave no murmur when fluid was forced from the right ventricle, but if a small window was cut in the pericardium so that the conus and pulmonary artery bulged, a systolic murmur at once appeared. Another suggestion69 is that with dilatation of the right heart, the enlarged conus pushes up the pulmonary artery which then becomes kinked, shorter and broader. Violent contraction of the ventricles during vol. xlviii. no. 9 613 2 u 2 D. M. Lyon effort or excitement may act in this way. Apparently a large number of conditions may lead to deformity of the relatively non-resistant pulmonary artery in such a way as to give rise to a murmur. Time.?Functional pulmonary murmurs accompany rather than replace the first sound ; they may begin early or a little after the commencement of the first sound and fade away during the systolic pause. Site.?Since the murmurs have their origin at or near the valve, the position of maximum audibility is the same as for an organic lesion. Propagation.?-The murmurs are usually heard over a very limited area, but if loud will be carried up and to the left as in the case of organic murmurs. The characters range from a mere impurity to a loud rasping. Usually the bruit is soft and blowing, more rarely harsh and rough. Its pitch is moderately high. The intensity varies considerably ; usually the murmur is weak and faint and it is never as loud as that of pulmonary stenosis. Most are very short in duration. The posture of the subject has a considerable influence. The majority are loudest or are only heard in recumbency, 59 and usually disappear when erect, yet Perry notes that in children the murmur may be best heard in the erect position. Respiration.?Most of the functional pulmonary murmurs are absent at some phase of respiration. Often the bruit disappears during inspiration or when a deep breath is held, the filled lung becoming interposed between the pulmonary vessel and the chest wall, and conversely the murmur reappears or is increased during expiration or when the chest is emptied and the breathing stopped. Cardiac Rate.?The murmur may be absent when the heart is quiet and only appear when exertion or excitement speeds up the rate sufficiently. The second pulmonary sound is often accentuated, but there is no enlargement of the heart and no thrill is present.

Murmurs due to Cardiac Displacement 44 " Latham noted that strange things may happen when the chest is deformed and the heart displaced." Functional murmurs may apparently occur at any of the four valve areas when there is cardiac displacement. They have been found 614 The Significance of Systolic Murmurs

when the diaphragm is pushed up by ascites, flatulence, obesity or pregnancy, and when the mediastinum is displaced laterally 18 by pleural effusion, lung contraction or tumour. Elliotson described a case of ascites with a systolic murmur which disappeared after paracentesis and returned as the fluid reaccumulated. The Subclavian Murmur A bellows sound over the subclavian artery was recorded by Laennec.43 Corrigan,13 in the course of his investigations, discovered that if the stethoscope were placed under the outer half of the clavicle a murmur could easily be produced by compressing the subclavian with a finger above the clavicle. A systolic murmur may commonly be noted under the clavicle, chiefly at the junction of its middle and outer thirds. It is specially found when the patient is erect and holding up his shirt. Close observation will show that the bruit depends on the position of the arm. It is present when the elbow is level with the shoulder and disappears at a certain point as the arm is brought down to the side, to reappear as it is raised again. This spontaneous murmur has been attributed to ~a overdeveloped muscles (Richardson's carpenters' murmur), to stretching of muscles across the vessel, to an overacting or hypertrophied heart, and it occurs more readily in anaemia. A similar bruit may be due to compression or traction on the vessel wall in cases of cervical rib, apical phthisis, enlarged mediastinal glands or tumour. Theoretically either narrowing or dilatation of a part of the vessel would account for the phenomenon. The murmur of itself is of no importance.

Pericardial Sounds The earliest evidence of acute pericarditis is usually to be found near the base of the heart, from which it spreads down- wards over the precordium. The area involved does not correspond with the ordinary sites of valve murmurs ; it is usually rather restricted and the sounds are not transmitted. Most often to-and-fro sounds are produced, a double or triple rhythm not exactly synchronous with the heart sounds, which are not entirely replaced. Sometimes only a systolic rub is evident. The noise appears more superficial and closer to the ear than a valvular murmur. In character pericardial friction ranges from the gentle rustling of a silk fabric or the crumpling of paper to the rasping of creaking leather. It is harsh, 615 D. M. Lyon scratching, scraping or grating and jerky. Pressure by the stethoscope intensifies the sound, as also does a deep inspiration though this is not invariable. Posture may modify the sounds. They are usually loudest when the patient is erect or leaning forwards and may be absent in the recumbent position. Lying on the left side may bring out the sounds while they may dis- appear when the patient turns to the right. Friction is very variable, readily altering its position and coming and going within a very short time. If intense, a rub may be easily appreciated by the hand. At times pericarditis may produce sounds which are almost undistinguishable from intracardiac murmurs.10'66 A small area of pericardial thickening over the anterior surface of the heart, the milk spot or soldier's spot, is a common post-mortem finding, and the question has often been raised as to whether this may give any indication of its presence during life. There is little evidence that it does so, but the possibility is mentioned by several writers.0'19'2G'51'73 A murmur due to this cause should be intensified by pressure. 44 Latham describes a scratch or scrape under the lower part of the sternum in healthy individuals with a long hanging heart (cardioptosis). A xiphisternal crunch or superficial friction-like sound, either systolic or diastolic, often heard only when the subject leans forwards or to the left, has been recorded by Norris and Landis.56 It may be associated with the inferior sterno- pericardial ligament. Conclusions

A very large proportion of systolic murmurs are functional and innocent, but all demand the most careful study before they can be regarded as harmless. Many closely resemble organic murmurs and can only be distinguished with difficulty. In studying a murmur its time, site and propagation are most important, but the effects of respiration, posture and cardiac rate should be specially noted. Several examinations may be required before a diagnosis is made, and no final decision should be taken until the pulse rate is within normal limits.

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