Diseases of the heart

Contents

Chapter. Page.

I. Introduction to Diseases of the Heart . 11

II. The Diagnosis of Diseases of the

Preface

This little book was never intended to aspire to the dignity of a treatise on diseases of the heart. The primary object was to make it useful to the practical physician in the diagnosis of cardiac diseases. The cardiac diagnostician is often like the veterinarian, for his diagnosis is based essentially on objective signs. He must depend largely on the Baconian or inductive method of ratiocination, in contradistinction to the deductive method.

The former analytic method of diagnosis is a conclusion drawn from concrete facts. Mistakes in diagnosis may be attributed to the following causes: 1. Incomplete or careless examination. 2. Misinterpretation of symptoms, due to errors in judgment. 3. Ignorance of the methods of examination. 4. Prejudiced preconception. 5. Incompleteness of medical diagnosis. 6. Placing too much reliance on the results of treatment. 7. Incomplete history of the case, and the incomplete development of symptoms. 8. Simulation or dissimulation on the part of the patient.

1. Errors in diagnosis are not so much due to ignorance as carelessness. Sir William Savory tritely remarks, "Consciousness of one's ignorance may do much to avert the errors of carelessness, and he who has confidence in his own judgment should of all men be most careful in inquiry."

Unfortunately, we of to-day treat the disease, but not the patient. "And I said of medicine, that this is an art which considers the constitution of the patient, and has principles of reason and action in each case." It is but a few years ago, that a physician punctured a pregnant uterus with a trocar, believing that he was dealing with a case of ascites. We recall the grave error occurring in the practice of a famous English surgeon who mistook a swelling in the neck for an abscess, who, with more precipitation than reflection, plunged his lance into the tumor and death from hemorrhage resulted.

2. Under the caption of misinterpretation of symptoms due to errors in judgment, mistakes may arise from (a) placing too much reliance on the subjective symptomatology; (b) giving undue prominence to one symptom to the exclusion of others; (c) grouping symptoms which are the effect of disease, and not the disease itself. When the pathologist makes an autopsy he records many of the pathological conditions found, as anatomic diagnoses. The clinician should be similarly guided. It would appear at times as if, in our struggle to establish a diagnosis, it would be better to make none at all, rather than group symptoms under such equivocal expressions as pseudoangina, arrythmia, cardiac palpitation, etc. Such expressions mean practically nothing in etiologic diagnosis.

3. Ignorance of the methods of examination is responsible for many unfortunate mistakes. The rejected applicants of insurance companies furnish a large contingent. Nephritis is diagnosed because albumin is present in the urine, diabetes, because sugar is found, and heart disease because murmurs are heard. An unprincipled physician could reap a harvest, by putting in condition for re-examination many rejected applicants, diseased or otherwise, for life insurance.

4. Prejudiced preconception arises from two causes: (a) Placing too much reliance on the history of the patient; (b) being misled by first appearances. Like the critic who never read a book before he received it because he might be prejudiced, so it should be with the physician — he should not learn the history of his patient before he examines him. Diseases present such various pictures, that with our mental astigmatism, we can see anything we want. The personal history of the patient should only be used in confirming the objective examination.

5. When a disease runs a typic course diagnosis is, as a rule, easy ; but when the affection is a typic, one is frequently led into error. The physician is too often inclined to misinterpret the limitations of his art, mistaking the latter for his own delii^ quencies. Myocarditis is more often an anatomic than a clinic diagnosis. Differentiation between cardiac dilatation and pericardial effusion is exceedingly difficult at times and to puncture the dilated heart with the idea that the latter condition is present is a gross error. Treatment should never be attempted before a diagnosis »is made. Better no treatment than meddlesome therapy. Qui bene dignoseit, bene curat. It is related of Frerichs, that after examining a patient, he was in doubt about the diagnosis. The patient insisting about knowing the nature of his trouble, Frerichs comforted him with the assurance that the diagnosis would be determined at the autopsy.

6. We are frequently led into error by mistaking recovery for cure, thereby ignoring the vis medicatriz naturae. I have seen many patients with organic cardiac murmurs, the latter becoming less intense after the administration of chalybeates. Under the circumstances, one would be inclined to regard the murmurs as anemic. Upon more mature consideration, this view would be dispelled. Impoverishment of the blood attends nearly all organic cardiac affections and only succeeds in intensifying the murmurs, hence iron only removes the factor in intensification.

7. Diagnosis must be held in abeyance in many cases owing to undeveloped symptoms and incomplete history of the case. Problematic diagnoses are elusive, and a diagnosis altered to correspond with each stage of the patient's illness is no diagnosis at all.

8. Disease is expressed in a manner peculiarly its own. The interpretation of the signs constitutes diagnosis. The translation may be correct, partially correct, or wrong. In all three instances the result, as far as the patient is concerned, will, as a rule, be the same, provided no treatment is instituted. To treat a disease, other than by expectant methods, where the diagnosis is wrong, is adding insult to injury.

December, 1900. San Francisco.

Introduction

The heart with its valvular apparatus acts like a pump with a suction and pressure valve. During diastole, it sucks the blood from the veins, and during systole drives it into the arteries. Therefore during diastole the pressure in the veins sinks and rises in the arterial system during diastole. This difference in pressure causes the blood to circulate.

COMPENSATION.

All heart affections, whether of the valves, muscle or pericardium, result in circulatory disturbances and are characterized by diminished pressure in the arteries and increased pres* sure in the veins, with retardation of the blood current in the capillaries. When the heart by increase of power and volume opposes the local and general disturbances, the lesion is said to be compensated, and a well compensated valvular lesion may be unattended by subjective symptoms.

Compensation fails when the heart muscle (myocardium), in consequence of nutritive disturbances, degenerates. A valvular heart trouble, especially in children, retards development and

DISEASES OF THE HEART.

nutrition, leading to cardiac cachexia. The notable tissue changes are thickening of the nose and lips and clubbing of the finger ends.

Overloading of the veins leads to the accumulation of fluid in the tissues ; beginning first in the feet, it gradually invades the rest of the body. Fluid also accumulates in the serous cavities (pleura, pericardium, brain ventricles). As a rule, the peritoneum is the first serous cavity invaded (ascites). The chief cause of cardiac dropsy is disease of the mitral valve, and especially mitral stenosis.

Cyanosis of the skin is an early sign and appears as soon as the pulmonic circulation is disturbed, therefore cyanosis is more evident in mitral than in aortic lesions. The cutaneous veins are filled with blood and may become varicosed. Jaundice, due to catarrh of the bile passages, is not uncommon. Cutaneous hemorrhages from rupture of the capillaries or caused by emboli may develop.

The temperature of the body may be normal or lowered, owing to the retarded circulation. Intercurrent elevations of temperature may be caused by emboli in the viscera or lung infarcts.

PULSE.

The pulse has a specific character in nearly every valvular lesion. Disturbance of compensation gives a frequent, irregular, soft and feeble pulse. An intermittent pulse is caused by feeble heart contractions which are not strong enough to drive the blood to the radial artery. In such instances, if the heart is auscultated synchronously with palpation of the pulse, there are more heart tones than pulse beats.

Palpitation of the heart, a frequent symptom, may be subjective, objective, or both. Pain in the precordia radiating to the left arm, neck or umbilicus, gives rise to symptoms not unlike angina pectoris. This precordial pain is especially frequent in aortic incompetency and has been attributed to irritation of the cardiac plexus by the dilated aorta.

BLOOD-VESSELS.

Emboli and thromboses occur. Emboli from the right ventricle pass into the pulmonary arteries and cause hemorrhagic infarctions. Emboli originating from the left ventricle go to the extremities, skin, retina or the viscera. Embolism of the spleen is manifested by a sudden chill, fever, perspiration, pain in the splenic region and enlargement of that viscus.

To the foregoing symptoms, hematuria is added when the embolus attains the kidney. An embolus of the brain reaches that organ usually through the left carotid artery.

LUNGS.

Dyspnea, especially on exertion, is frequent. The dyspnea of heart disease is out of all propor-

DISEASES OF THE HEART.

tion to the physical changes in the lungs. Difficult breathing is usually caused by pressure of the enlarged heart on the lungs, disturbed pulmonic circulation, hydrothorax, ascites or bronchial catarrh.

Hemoptysis occurs frequently in mitral disease. Hemorrhage may be due to congestion, rupture of vessels or hemorrhagic infarcts. Hemoptysis is most frequently the result of infarcts, and the latter are frequent in aortic disease. Lung infarcts lead to a brownish red sputum not unlike that of pneumonia. Stress has been laid on the fact that in hemoptysis of cardiac origin, the blood is clotty and blackish blue in color.

Edema of the lungs is a frequent cause of death. It gives rise to diffuse crepitant rales and serous expectoration. Valvular heart troubles predispose to inflammatory lung affections. Glottis edema may complicate heart lesions. Epistaxis is not infrequent.

GASTEECTATIC DYSPNEA.

A frequent cause of dyspnea in heart disease is acute dilatation of the stomach. After meals patients complain of difficult breathing and distress in the precordia, and death has not unfrequently followed an indigestible meal. I have called this condition gastrectatic dyspnea, because it is always associated with a dilated stomach. In some instances dyspnea is associated with symptoms of angina pectoris. Many patients makeno mention of dyspeptic symptoms. They complain of pressure or weight in the sternal or precordial region, and often add that eructation will relieve the pressure. This symptom, as I have assured myself after examination of a number of cases, is dislocation of the heart upwards by an acute or chronically dilated stomach. Some years ago I reported a case of gastroptosis and merycismus, with voluntary dislocation of the stomach and kidneys.* This phenomenal case taught me one fact in particular, how easily the heart could be displaced by dilatation of the stomach. The individual in question could, by buccal insufflation of the stomach, cause his heart to disappear behind the lungs, so that percussion of the precordial region yielded no dullness on percussion. This case directed my attention to a correct investigation of all individuals presenting themselves for the treatment of slight dyspeptic symptoms in whom sternal pressure was the chief subjective symptom.

In all such cases the diminished area of cardiac dullness bears a distinct relation to the severity of the pressure symptoms. The removal of ingesta and gases from the stomach restores the heart to its normal position and feeble heart tones become strong.

*Medical News, April 13, 1895.

DISEASES OF THE HEART.

Not infrequently true asthmatic attacks, asthma dyspepticum, v/ere present. . The patient is unable to get rid of the gases owing to a spasm of the

Fig. I — Skiascopic picture of the outline of the heart and stomach before swallowing the seidlitz powder.

sphincters of the stomach; the distended stomach pushes the diaphragm upward, dislocating the heart, and induces typical attacks of asthma.

To quickly detect a dilated stomach encroaching on the chest organs, the following percussion method will be found practical. The circular tympanitic stomach-lung region formed by the stomach beneath the lower lobe of the left lung gradually disappears behind the axillary line if the stomach is normal, but if dilated, the tympanitic sound may be traced to the vertebral column. Sometimes in dyspeptic asthma relief is quickly obtained by introduction of the stomach tube and allowing the gases to escape. The following illustrations describe more fully than words the influence of a dilated stomach on the position of the heart. They are rough reproductions from the fluoroscopic picture with the use of the X-rays. In the average examination of the chest by the X-rays, the portion of the stomach which is in direct contact with the chest wall is obscured by the shadow cast by the spleen, but in this patient no spleen shadow being present and the contour of the stomach being clearly defined, opportunity was afforded to test the influence of a stomach distended by a seidlitz powder on the position of the heart.* Every phase of the stomach distention was followed in the fluoroscopic picture.

*Later a similar case came under my observation. See "Note on a Case of Nervous Eructations Studied by Skiagrams," Philadelphia Med. Journal, Aug. 12, 1899.

DISEASES OF THE HEART.

CARDIAC ASTHMA.

Cardiac Asthma closely simulates bronchial asthma, but the former is associated with some anomaly of the heart or arterial system. If such

Fig. 2 — Shows the same organs after distention of the stomach by gas.

anomalies exist, asthmatic paroxysms may result, whenever the pressure in the capillaries of the lungs rises. Such rise in pressure may follow an

INTRODUCTION.

increased or diminished blood pressure in the aorta. In either instance, the capillaries of the lung alveoli become surcharged with blood, which in turn make the alveolar walls rigid and incapable of distension, thus diminishing the respiratory area. The following table may assist in differential diagnosis :

BRONCHIAL ASTHMA.

Usually absent.

CARDIAC ASTHMA.

Signs of cardiac disease (valvular lesion, arterio sclerosis, fatty heart).

Dyspnea is equally inspiratory and expiratory.

Pulse in the early stage of paroxysm may be strong, but it soon becomes soft and small.

Percussion shows an extension of the borders, of the lungs and obliteration of the area of superficial cardiac dullness.

Auscultation shows an abscence of rales unless complicated by edema of the lungs.

DIGESTIVE APPARATUS.

Yenous stagnation conduces to chronic catarrh of the gastro-intestinal mucous membrane, resulting in dyspepsia, constipation, diarrhea and

Dyspnea is expiratory.

The pulse is usually one of increased tension throughout the paroxysm.

The extension of the lung borders is more pronounced than in cardiac asthma.

Sonorous and sibilant rales are always heard, louder during expiration than inspiration.

hemorrhoids. Gastralgia occurring in cardiac lesions may mislead the physician if the diagnosis is of a stomach trouble.

LIVER AND SPLEEN.

The liver participates early in the circulatory disturbances. Owing to the venous engorgement of the inferior cava, the hepatic veins cannot unload, and the liver in consequence swells and may be felt below the border of the ribs as a hard and painless mass. Later in the disease, owing to atrophy of the liver cells, the organ may become reduced in size. Not infrequently the enlarged liver may pulsate owing to transmitted pulsations from the aorta. It is well to remember that the knee-elbow position will usually cause the disappearance of transmitted pulsations. Stagnation of blood in the portal circulation leads to venous engorgement of the spleen, stomach and intestines, with enlargement of the first mentioned viscus.

From the quantity and constituents of the urine the severity of the compensation failure may be gauged. The lower the blood pressure in the aorta and the higher the blood pressure in the venae cavse, the more the urine partakes of the characteristics of passive congestion of the kidneys. The urine is reduced, of high specific gravity, contains albumin, casts, and often blood corpuscles. Uric acid is increased and is deposited as a brick dust sediment.

NERVOUS SYSTEM.

Aortic lesions, particularly owing to brain anemia, are often complicated by syncopal attacks. Brain hyperemia complicating heart lesions is characterized by attacks of fainting, fullness in the head, ringing in the ears, etc. Nitrite of amyl inhalations are of signal advantage in diagnosis. This drug will ameliorate symptoms of brain anemia and intensify those of hyperemic origin. An embolus in the left arteria fossae sylvii will cause hemiplegia on the right side, associated with aphasia. Temporary aphasia may occur without an embolus and must often be attributed to mere circulatory disturbances. Mental diseases are not frequent in heart lesions. In some cases a real intellectual disturbance exists. Observations are recorded of maniacal delirium in patients with mitral lesions. Such cerebral troubles may be remedied by treatment directed exclusively to the heart.

RELATION OE DISEASES OF THE HEART TO OTHER DISEASES.

An individual with a heart lesion assumes a grave risk when attacked by other diseases. This is notably the case in febrile affections. In fever, the organs show cloudy swelling; a like change occurs in the muscles, and the heart manifests the

DISEASES OF THE HEART.

granular alteration of its fibres to the highest degree. These tissue changes arise from contact with the poisons circulating in the blood and from the accompanying rise of temperature associated with disturbances of nutrition. A febrile affection therefore may seriously implicate the functions of the heart in valvular lesions.

Intercurrent diseases of the lungs tax the functions of the right heart to the utmost.

Pregnancy always causes hypertrophy of the heart, but this recedes in the healthy woman after delivery. Cardiopathic patients are predisposed to acute exacerbations of endocarditis, and a large number are always in danger of miscarriage. Durosier noted that out of forty children born of cardiopathic mothers, thirty-seven died before attaining the age of six years. The most unfavorable lesion to the mother from the point of prognosis is mitral insufficiency, the mildest, aortic insufficiency. The most serious complications, and the greatest danger of death for the mother, appear about the seventh and a half, or the eighth month. Cardiopathic mothers should not nurse their infants because lactation augments heart hypertrophy.

Endocarditis is regarded by some as the cause of chorea; particles of fibrin are supposed to pass from the valves as emboli to the cerebral vessels. At any rate, endocarditis is very common as a complication, although many of the heart murmurs in chorea may be caused by anemia or the rapidly acting heart.

The belief was at one time current that an individual with heart disease was in no danger of contracting phthisis. As a rule (pulmonary stenosis the exception), pulmonary tuberculosis rarely develops in an individual with a valvular heart lesion. In 277 autopsies on individuals who during life suffered from valvular trouble, Frommalt found phthisical lung changes in 8 per cent of the cases. These statistics show the infrequency of phthisis complicating valvular lesions, since Biggs reports that more than 60 per cent of his autopsies showed lesions of pulmonary tuberculosis.

ETIOLOGY OF DISEASES OF THE HEART.

Endocarditis is the usual cause of valvular heart lesions. That part of the endocardium performing the most work is the first to become involved and suffer most. This explains the rarity of endocarditis on the right side in adults and the infrequencv of congenital lesions on the left side of the heart. The process usually implicates the valvular endocardium and is therefore known as valvular endocarditis. In adult life, about one-half the cases of endocarditis occur on the mitral valves; of the remaining 50 per cent, about 94 per cent occur on the aortic valves ; the remaining cases are divided between the valves of the right side, the tricuspid valve being in the ascendency. It is customary to speak of the following forms of endocarditis :

(a) Acute \ S ™? e ' ,

( malignant.

(b) Chronic or indurative.

(a) The acute simple endocarditis is caused by acute articular rheumatism in 20 per cent of the cases. Among the other causes are : the infectious diseases of children, tonsillitis (by many regarded as the avenue of rheumatic infection), pneumonia, and diseases associated with blood intoxications, like diabetes, gout, cancer, and nephritis, especially the interstitial form. Various organisms, like strepto- and staphylococci, gonococcus, and even the bacillus tuberculosis, have been found in and on the affected valves, but their casual relationship has not been demonstrated.

The malignant form is of microbic origin and is secondary to some infectious disease. The majority of cases develop during an attack of croupous pneumonia. The other diseases associated with the infectious process are: pyemia, septicemia, puerperal fever, gonorrhea, erysipelas, puerperal fever, diphtheria and rheumatism.

(b) Chronic endocarditis results from the acute forms and from syphilis, alcoholism, gout and excessive work for any one valve,

RESULTS OF ENDOCARDITIS.

When restitution of the valve does not take place (rare), one of two conditions of clinical importance occurs, narrowing, obstruction or stenosis, or insufficiency or incompetency of the valves. In either instance, murmurs are heard resulting from obstruction to the onward flow of the blood or from leakage backwards through a closed but incompetent valve. The former are known as obstructive, the latter as regurgitant murmurs.

RESULTS TO THE HEART.

The inevitable consequence to the heart in a valvular lesion is increased work, leading to hypertrophy or dilatation.

Hypertrophy is muscular thickening of the walls of one or more cavities of the heart, and rarely occurs without some dilatation of the cavities. Increased work of the heart, when nutrition is plentiful, is followed by hypertrophy. Overwork, beyond the nutrition and muscular power of the heart, results in dilatation. Hypertrophy is a favorable compensatory condition in cardiac lesions ; it is the response of the cardiac muscle to an increased demand for power. It can only develop when the health of the organism is maintained at the proper standard, and when this fails the compensation attempted by nature must fail, and then hypertrophy passes into dilatation.

Heart strain is a prolific etiologic factor in dis-

^O DISEASES OF THE HEART.

eases of this organ and of the aorta. The initial effect of prolonged exertion is dilatation of the right side of the heart. The effect of sudden strain is on the aortic area. Peacock found, in 17 cases of rupture of the heart valves after sudden strain, that the aortic valves were implicated ten times, mitral valves four times, and the tricuspid valves three times. Schott* has demonstrated in a series of skiagraphs that dilatation of the heart after wrestling can be demonstrated by the Eoentgen rays.

In recent years, heart disease, resulting from overstrain after bicycling, has been frequently observed. I have examined a few individuals with the X-rays who have done "century runs," and have demonstrated dilatation of the right heart following such foolhardy attempts. I have personal knowledge of five individuals who have become heart cripples from excessive bicycling.

The size of the heart chambers varies in health. In severe exertion the chambers dilate, especially those of the right side, to accommodate themselves to the increased quantity of blood; this compensation on the part of the heart is "the getting of wind," as it is called in training. When an individual in poor condition subjects himself to heart strain he suffers from rapid and feeble pulse, cardiac dyspnea and precordial pain, and for months

*Medical Record, March 26, li after he may be unfitted for severe exertion or became permanently crippled. Systematic and judicious muscular exercise develops heart hypertrophy, a propitious condition when great endurance is demanded. Injudicious exercise weakens the heart.

Relative valvular insufficiency (i. e., normal valves which are no longer capable of completely closing the orifices of the heart), especially of the tricuspid valves, frequently follows heart strain. In men the aortic valves are more frequently implicated than in women. This is owing, no doubt, to the fact that bodily exertion predisposes to arterial disease. Among the laboring classes valvular lesions are most frequent.

FREQUENCY OF INDIVIDUAL VALVULAR LESIONS.

In extra-uterine life the most frequent valvular lesion is mitral insufficiency, then follows mitral stenosis, combined with mitral insufficiency, then aortic insufficiency, then aortic stenosis, and finally aortic stenosis combined with aortic insufficiency. Combined lesions are not infrequent. Mitral and aortic lesions may coexist and less often mitral and tricuspid lesions. In children, the most common combination is aortic and mitral insufficiency.

PROGNOSIS OF DISEASES OF THE HEART.

The prognosis in valvular lesions is unfavorable. Cure may be spontaneous, but is never attained by medication. Aortic are more favorable than other lesions, owing to the ability of the voluminous left ventricle to compensate the defect. Pulmonary lesions are especially unfavorable, owing to the frequency of phthisis complicating such lesions. Combined lesions of different valves are more unfavorable than lesions of individual valves, owing to the increased work thrown on the heart. The social position of the patient influences the prognosis. Occupation which demands little muscular effort and permits a sedentary life favors longevity. The stronger the constitution the greater the likelihood of the heart being able to meet the increased demands made on its power. Valvular lesions acquired in childhood soon result in compensatory disturbances.

Mechanical troubles of circulation when the heart muscle is inadequate to perform its task furnish an unfavorable prognosis and lead to a lingering illness, death resulting eventually from paralysis of the heart, blocking of one of the branches of the coronary arteries, lung edema or debility. In other instances death is sudden from heart rupture or cerebral complications. So long as an efficient compensation is maintained in valvular disease, even the most serious valve lesion is unattended by inconvenience to the patient. Sir Andrew Clark summarized the following conditions which justified a favorable prognosis : Good general health; just habits of living; no exceptional liability to rheumatic or catarrhal affections; origin of the valvular lesion independently of degeneration; existence of the valvular lesion without change for over three years; sound ventricles, of moderate frequency and general regularity of action; sound arteries, with a normal amount of blood and tension in the smaller vessels; free course of blood through the cervical veins; and lastly, freedom from pulmonary hepatic and renal congestion.

Chapter II. The Diagnosis Of Diseases Of The Heart

SIGNIFICANCE OF MURMURS.

No fallacy in medicine has been more carefully nourished than the belief that a cardiac murmur is always indicative of heart disease. Some of the most serious heart affections are unaccompanied by murmurs. "The idea that a murmur in itself and by itself is a serious thing dies hard" (Shattuck). Sir Andrew Clark gave utterance to the truism "that a murmur in itself is of little or no moment in determining the prognosis of any given case. Osier voices the opinion of the skilled cardiac diagnostician as follows: "Practitioners who are not adepts in auscultation and feel unable to estimate the value of the various heart murmurs should remember that the best judgment of the conditions may be gathered from inspection and palpation. With an apex beat in the normal situation and regular in rhythm, the auscultatory phenomena may be practically disregarded." THE APEX BEAT.

We must always remember that disease of the heart valves of any consequence to the patient, always leads to functional and structural heart changes and unless the latter can be demonstrated, the diagnosis of valvular disease should be held in abeyance. Fowler is responsible for the epigram: "That the position of the cardiac apex is the key to the diagnosis of nearly all affections of the chest and heart."

The normal location of the apex beat excludes dilatation, hypertrophy, pericardial effusion and heart dislocation.

CARDIAC MURMURS.

Adventitious sounds originating in the pericardium heart and blood vessels are known as murmurs. The auscultation of a murmur suggests many problems in diagnosis. Having determined the presence of a murmur the first problem to unravel is its origin. The most frequent murmurs are endocardial in origin and they are divided into organic (if caused by anatomic changes of the heart or blood vessels) and inorganic or functional murmurs (caused by changes in the quality of the blood. An organic murmur may be obstructive or regurgitant. Two problems await solution: First, the seat of the murmur; second, the nature of the murmur.

The seat of the murmur is determined by noting its position of maximum intensity and the direction of its transmission. These facts apprise us of the valve orifice affected.

THE ORIFICE AFFECTED.

The position of maximum intensity of a murmur usually occurs at the point where the normal valve sound is best heard in health. We must not forget that the heart orifices are closely situated and therefore murmurs are created within a limited area; if it were not for the fact that murmurs have directions of selective propagation it would be impossible to determine at which valve orifice the murmur was generated.

DIRECTION OF TRANSMISSION", NATURE AND TIME.

In general, systolic murmurs of aortic origin are transmitted upwards from the base. Systolic murmurs of mitral origin are transmitted toward the axilla. The transmission of a murmur is in the direction of the currents which produce them.

Our next duty is to determine the nature of the murmur, which is ascertained by noting the time of the murmur and the direction of its propagation. Organic endocardial murmurs may be obstructive when there is obstruction to the onward flow of blood, the nature of the lesion being a stenosis and regurgitant murmurs when there is leakage backwards through a closed but incompetent valve, the nature of the lesion being an insufficiency.

Organic heart murmurs have a definite relation to the cardiac cycle and we distinguish systolic, diastolic and 'presystolic murmurs.

SYSTOLIC MURMURS.

The systolic murmurs arise from aortic obstruction, and mitral and tricuspid regurgitation. Systolic murmurs are synchronous with the carotid pulse, therefore in a rapidly acting heart, the time of the murmur may be determined by palpation of the carotid pulse during auscultation. The radial pulse should not be selected because it is felt too long a time after systole.