Cardiac function

“ When such cardiac troubles are present, the objective examination of the heart shows in the early stage no gross abnormality; at most the heart-tones seem somewhat weakened, with a moderate enlargement of the area of percussion-dulness, whilst the impulse is displaced a little outwards, and is weaker than normal. ”

“ But when we come to consider cardiac strain a little more closely, it may be just as easily maintained that every dilated heart, every dilated cardiac chamber, every dilated blood-vessel has been strained. Whether, on the one hand, valvular disease, Bright's disease or emphysema, or, on the other hand, myocardial degeneration, has disturbed that cardinal condition of a normal circulation that the driving power must always exceed the resistance ahead, over-distension and dilatation of the cavities, with excessive stretching of their walls, constitute or consist in mechanical strain. ”

“ The action of the heart at first is to make it beat fuller and stronger, but if continued, the effect is also one of paralysis of its [Pg 273] muscle and a diminution of the output of work done, and finally it is a paralyzer of the heart’s action. In some persons, through its injury to the cardiac blood vessels and intrinsic muscle of the heart, it sets in motion those morbid processes which result in angina pectoris. ”

“ The heart's action is increased, the pulse is quickened, an excess of blood is forced into the vessels, and from their becoming engorged and dilated the face gets flushed and the retina congested—all the usual concomitants of a general engorgement of the circulation being the result. Instead of paralyzing the vagus by section, and thereby arresting its inhibitory cardiac nerve-power ”

“ What method might be followed with advantage in making a complete diagnosis of heart disease in older subjects?
A man of 60 consults us about his heart. He says that it has caused him a good deal of concern lately. More specifically he describes a sense of oppression behind the sternum as often as he exerts himself, and palpitation with consciousness of irregular [32] cardiac action when he goes to bed. We inquire for other familiar cardiac symptoms, such as pain, angina, fluttering, faintness, giddiness, and a sense of impending death. ”

“ In the former group of cases, the enhanced activity of the heart is perceptible, not only by auscultation, by which we usually find the heart-sounds quite pure, but also by inspection, which shows us the violent agitation of the thoracic wall and increased pulsation of the carotids. On percussion, no change is found in the area of cardiac dulness. The frequency of the pulse is increased, usually reaching 120 to 140 beats per minute ”

“ Although the pericardium and heart are situated in the median plane, percussion and auscultation should be performed on the left side, since the anterior and cardiac lobes of the left lung are less developed than those of the right; but the heart can be auscultated on the right side, as is advisable at times. ”

“ The cardiac disorder is, however, the most constant, and, pathologically, the most important, and therefore the affection may be considered as one of the neuroses of the heart. In this article the functional disorders of the heart's action, irrespective of angina pectoris and exophthalmic goitre, will be first considered, and afterward these two affections will receive separate consideration. ”

“ The implication of the fibrous structures of the pericardium and heart and especially of the valvular structures is a common lesion, and to be dreaded more than all others. In all animals this tendency to cardiac lesion is well marked, but especially in solipeds in which the great demands made on the heart during rapid paces, heavy draught, jumping, etc., severely strain the cardiac mechanism. ”

“ This load of the heart is also shown by an increased pulse rate and increased respiratory efforts. In cardiac failure, as the systolic pressure falls the diastolic is likely to be increased, and the pressure pulse thus diminishing, allows insufficient blood to go to the medullary centers, and death soon occurs. ”

“ In such cases the signs of degeneration of the heart are very striking: weakening of the cardiac impulse, notable faintness of the sounds of the heart, occasionally reduplication of the second sound, a galloping rhythm, while percussion shows the existence of considerable dilatation of the left, and still more frequently of the right ventricle; in many cases also we have angina pectoris, passive hyperæmia of the lungs, the mucous membranes, and the extremities; and sudden death sometimes ensues. ”

“ I believe that one can speak with some confidence on this subject. The middle-aged patient who over-stretched his cardiac walls as a youth may be comforted with the opinion that the condition is not a fatal one. ”

“ TESTS OF HEART STRENGTH If both systolic and diastolic blood pressure are taken, and the heart strength is more or less accurately determined, mistakes in the administration of cardiac drugs will be less frequent. Besides mapping out the size of the heart by roentgenoscopy and studying the contractions of the heart with the fluoroscope, and a detailed study of sphygmographic and cardiographic tracings, which methods are not available to the large majority of physicians, there are various methods of approximately, at least, determining the strength of the heart muscle. ”

“ Once commenced, the cardiac dilatation tends to increase automatically; for the more the organ dilates the more difficult does it become for it to contract, the greater is the incompetency of the valves, and the more the blood stagnates in and over-distends it. ”

“ Not only is the respiratory centre stimulated but the cardiac centre is acted upon both directly by the drug and indirectly for a time by the enormous rise in blood pressure due to the contraction of the arterioles all over the body. ”

“ Cardiac complications show themselves by shortness of breath, palpitations, hard intermittent, irregular or unequal pulse, blowing murmur with the first heart sound, and other signs of circulatory trouble. ”

“ But you will remember that we have found that cardiac dilatation may be present in every kind of cardio-vascular degeneration; that the arteries are naturally enlarged and thickened after middle life, and that we refused to call these changes morbid. Clearly, therefore, a purely anatomical diagnosis of this sort is insufficient. If you are asked what the prognosis is of fatty degeneration of the heart, you answer that you must first be told whether syphilitic or gouty disease of the coronary arteries, or strain, or alcoholism, or phosphorus-poisoning or anæmia is the cause of it. ”

“ We must of course accept the convulsive action of the phrenic and abdominal muscles, only it would seem that each such movement has its starting point in the contraction of the heart. In cases that show no relation in number 310nor succession with the heart beats, we can freely acknowledge a neurosis starting at a point different from the heart, but in all examples which are manifestly connected with heart movements, and readily curable by the heart-tonic digitalis, the recognition of the cardiac derangement as an initial factor is sound alike in pathology and practice. ”

“ It thus appears, that wherever a branch of the aorta goes to carry blood, there will be found a tributary of the upper or lower vena cava, to bring it back.
The succeeding engravings, will enable the reader to form a more definite idea of this important function of the system,—the circulation of the blood. The heart, in man, and in all warm-blooded animals, is double, having two auricles and two ventricles. In animals with cold blood, (as fishes,) the heart is single, having but one auricle and one ventricle. ”

“ In planning the treatment of the dilated heart of the middle-aged man who strained his circulation in youth and comes to us complaining of a recurrence of præcordial distress and breathlessness, we have to remember that there is left in the cardiac walls but a portion of that reserve of elasticity and that reserve of muscular energy which they normally possess and require to enable them to meet the stress of exertion. ”

“ The normal act of intercourse, in a young and sensitive woman, has already an exciting influence on the nerve apparatus by which the movements of the heart are controlled. The frequency of the heart’s action is greatly increased, the cardiac impulse becomes much stronger, there is marked pulsation of the peripheral arteries, the conjunctiva is injected, the respiration more frequent. These manifestations, which normally are quite transient, attain a greater intensity and exhibit a longer duration in persons affected with heart disease. ”

“ Treatment.—Treat the same as for hypertrophy of the heart.
Cardiac Atrophy.
—Definition.—Cardiac atrophy is a [325] decrease in the size, strength, weight, and activity of the heart.
Treatment.—Remove blood by drainage, and inject half strength fluid for the first part of the injection. The amount of fluid need not be as great as in the acute disease of the heart. Massage the face downward. Give cavity injection. For transportation, govern yourself according to the provisions of the transportation rules. ”

“ The heart, though mainly automatic in its actions, is controlled by the nervous system, which takes a share in regulating the contractions both of the heart and the arteries. On the due discharge of the respiratory function, too, the function of circulation is directly dependent: if the aeration of the blood is impeded the vascular activity is lowered ”

“ Examination of the heart gives negative results. The cardiac impulse is a little stronger than normal; the cardiac rhythm may be either regular or irregular, but actual intermission of the beats does not occur. The heart-sounds are pure, there is no murmur; the first sound, if altered at all, will be stronger, not weaker than normal. ”

“ But this period of cardiac excitement while persisting is soon complicated by other symptoms. As soon as the foreign body penetrates the pericardial sac, there is infection, which produces an active form of inflammation and abundant exudation. From this time the pulse becomes weaker and weaker, until, under the steadily increasing pressure on the heart, it is almost imperceptible. ”

“ Actions.—A cardiac and vascular tonic and stimulant, a motor excitant, paralyzant, anaphrodisiac, it is an indirect diuretic and an emetic, irritates the mucous membrane.
The heart is slowed but the force is increased; digitalis stimulates the cardiac motor ganglia, the inhibitory apparatus and the vaso-motor centers, contracting the arterioles and thereby greatly raising the arterial tension; large doses exhaust and paralyze the heart. ”

“ What I wish to maintain is that in cardiac degeneration of any kind, in chronic cardiac dilatation, and in the enlarged heart of Bright's disease and of emphysema, just as in ordinary valvular disease, attacks of distress, alarming both to patient and doctor, often occur which call for nothing more in the way of treatment than attention to some intercurrent influence—an indigestible meal, loaded bowels, a nervous shock, a thoughtless effort, a passing hardship or nervous strain. Digitalis and its allies, strychnine, alcohol, nitrites, iodides and the rest are out of place in such an event. ”

“ It is probable that there must have been some little circulation going on through the brain whilst the respiration lasted, and in fact, the slight fluttering pulse and feeble sounds of the heart, once or twice perceived, indicate that the circulation was not absolutely arrested. Under these circumstances, we may inquire why the action of the heart does not recover. If the circulation were going on in the coronary arteries, it might be expected that the blood from the lungs, which has been aerated by respiration, and freed from the narcotic vapour, would restore the action of the heart. ”

“ A very remarkable thing in experiments is the quickness with which pain disturbs the motion of the heart, accelerates it, renders it irregular, &c. We can always at will hasten respiration, by making the animal suffer; now the acceleration of the pulse is always prior to that of respiration, which appears to be determined by it. I am persuaded that if the diseases of the heart were as frequent on the right side as the left, they would often produce this reflux and this pulsation of the veins. ”

“ Let us assume either arbitrarily or by experiment, that the quantity of the blood which the left ventricle of the heart will contain when distended to be, say two ounces, three ounces, or one ounce and a half—in the dead body I have found it to hold upwards of two ounces. Let us assume further how much less the heart will hold in the contracted than in the dilated state, and how much blood it will project into the aorta upon each contraction, and all the world allows that with the systole something is always projected ... ”

“ The muscle of your arm contracts only at your will. But the heart is never quiet. Awake or asleep, whatever you are doing or not doing, it keeps steadily on.
Each time the heart contracts what happens? Let us begin with the right ventricle full of blood. It contracts; the pressure comes on all sides, and were it not for the flaps that close and shut the way, some of the blood would be forced back into the right auricle. As it is, there is but one way,—through the pulmonary artery. ”

“ It is supposed by being brought in contact with the air in the cells of the lungs. When the auricle receives this red blood, it contracts, forces it into the left ventricle beneath, then the ventricle in its turn contracts, forces it into the main artery, and by this and its branches it is carried to the extremities, to come back in one continual round, as long as life lasts. It is life; for the moment the heart ceases to contract and dilate, insensibility takes place, and death instantly follows. ”