Myocardium

“ PROGNOSIS The prognosis depends on the condition of the myocardium of the vagus. If this muscle is intact, and there is no pathologic condition in the sinus node (which can be proved by the successful results of treatment) , the removal of all toxins that could increase the activity of the heart, and the administration of digitalis, which will slow the heart by stimulating the pneumogastric control of the heart, will produce a cure, temporary, if not permanent. ”

“ The nutrition and activity of the myocardium can be increased and sustained by means of specific cardiac stimulants and tonics, such as strychnine, ammonia and the digitalis group of drugs; by hæmatinics, stomachics and laxatives to afford an abundant supply of healthy blood; by insuring wholesome nervous influences, one of the conditions of hypertrophy; and by the employment of the non-medicinal measures now so extensively used to increase the vigour and benefit the metabolism of the cardiac walls, particularly active and passive exercises and baths. ”

“ The great majority presented distinct thickening of the arterial walls. As I suggested in our study of the etiology, these pathological changes appear to be the result of malnutrition of structures (the myocardium, valves and arteries) worked at high pressure; and in addition to the local disturbance of metabolism in the cardiac and arterial walls, which are fed with gouty blood, there is the damaging effect on them of similar disease of the vasa vasorum and vasa cordis or coronaries. ”

“ The treatment is aimed at chronic heart disease, to develop a greater cardiac reserve strength; the whole object of the treatment is to strengthen the myocardium, either in conditions of its debility or in conditions of diminished compensation in valvular disease. Any treatment that will develop a reserve heart strength to be called on in emergencies, more or less similar to the reserve strength of a normal heart, tends to prolong the patient's life and health. ”

“ Many of the changes, which are no doubt in their essence conservative, lead to far-reaching consequences, by their interference with nutritive possibilities.
Diseased conditions of the myocardium are frequently associated with atheromatous degéneratibns of the coronary arteries, and angina pectoris is said to depend upon such state of malnutrition. ”

“ A force which is sufficient to send blood through elastic normal distributing tubes becomes totally insufficient to send the same amount of blood through tortuous and more or less inelastic tubes. As a compensatory process the pulse pressure increases. For this to increase, the left ventricular cavity dilates, the arch dilates, and as a greater force must be exerted to keep the increased mass in motion, the heart responds by hypertrophy of its left ventricle and becomes itself the subject of fibrous changes in the myocardium. ”

“ Whilst absolutely contra-indicated in all cases of valvular disease, it is of value in cases of cardiac hypertrophy with over-action. But the practitioner must be assured that neither valvular lesion nor degeneration of the myocardium is present. ”

“ It is atrophied as a consequence of prolonged compression.
Under the influence of the eccentric pressure of the liquid the pericardial sac is distended and comes in contact with the walls of the chest, to which it may adhere. The foreign body, especially if small, is not always easy to find.
The myocardium often displays interesting lesions. At first there is thickening, or more commonly sclerous degeneration, of the superficial layers covering the ventricles, and then appears a crop of little miliary abscesses. ”

“ 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. ”

“ The pericardium, or outer investing membrane of the heart, is frequently liable to inflammation, milked by a quickened and irregular respiration, and an action of the heart, bounding at an early period of the disease, but becoming scarcely recognisable as the fluid increases. The patient is then beginning gradually to sink. A thickening of the substance of the heart is occasionally suspected, and, on the other hand, an increased capacity of the cavities of the heart; the parietes being considerably thinner, and the frame of the animal emaciated. ”

“ It may be taken for granted, however, that hardly any serious illness can long continue without cardiac muscle disturbance. If endocarditis is present, soft systolic murmurs soon appear. With the acute myocarditis developing, the apex beat is less positive, less accentuated, and later it becomes diffuse and even feeble. The closure of the aortic valve is less typically sharp, showing that the blood vessels are not so thoroughly filled. The peripheral circulation is not so active, the blood pressure falls, and the heart becomes more rapid, especially on the least exertion. ”

“ The walls of the heart become soft and flabby, and are consequently weakened; the circulation in the coronary arteries and veins is sluggish.
It is almost invariably a chronic affection, coming on insidiously, and its [p. 790] existence may not be suspected until the disorder is well advanced, when some symptom, suddenly developed, directs attention to the heart.
After death the serous pericardium is found to be opaque, somewhat thickened, and to have an anæmic appearance. The opacity is due either to interstitial deposit or to the swelling of the epithelium. ”

“ The circulatory system presents many symptoms of importance. When the patient is recumbent and at rest, the heart's action is quiet, but on exertion or excitement the action becomes rapid, and there are palpitation, fluttering, and sometimes painful sensations in the cardiac region. Stairs are particularly trying to these patients. There may be slight enlargement of the heart, indicated by an increased area of visible pulsation, and an impulse in the third or fourth left intercostal space, near the sternum, is frequently seen. ”

“ We find valves for a similar purpose placed at the origin of the pulmonary artery and the aorta, which proceed from the right and left ventricles, and are the channels by which the blood flows through the former to the lungs, through the latter to the general circulation. The chambers of the heart are lined by a smooth membrane of a serous character, called the endocardium, which is often the seat of disease; and the whole is enclosed in a fibro-serous sac, called the pericardium. ”

“ The heart, the main pump of the circulatory system, rests on the diaphragm between the two lungs. The heart is enclosed in a smooth, moist membrane or sac, the pericardium, which allows it to dilate and contract without friction against the adjoining parts. There are four cavities in the heart, the right and left auricle, and the right and left ventricle. The auricles, which are thinner walled, collect blood from the veins, while the thicker and stronger walled ventricles force the blood into the arteries. ”

“ The same symptoms are noticed when the valves of the heart close their orifices imperfectly. In convalescence from lung diseases and in certain diseases of the heart a beat may be felt by the right hand for which no corresponding pulsation is felt in the radial artery by the left.
When the heart is hypertrophied the impulse is stronger and is associated with a full, strong, and rolling pulse. When it is atrophied 301the impulse on the chest and pulse beat are equally weak. When water exists in the pericardium the heart strikes the ribs with less force. ”

“ 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. ”

“ Heart Failure:—"In cases of cardiac weakness, the thing needed is not simply an increased rate of movement of the heart, or an increased volume of the pulse, but an increased movement of the blood current throughout the entire system. In the application of any agent for the purpose of affording relief in a condition of this kind, the peripheral heart as well as the central organ must be taken into consideration. In fact, the whole circulatory system must be regarded as one. The heart and the arteries are composed of essentially the same kind of tissue, and have practically the same functions. ”

“ The two primitive aortae lie at first in the ventral wall of the 644 pericardium, but with the folding over they come to lie in the dorsal wall and gradually bulge into the cavity as they coalesce to form the heart, so that the heart drops into the dorsal side of the pericardium and draws down a fold of the membrane called the dorsal mesocardium. In mammals A. Robinson (Jour. Anat. and Phys., xxxvii. 1) has shown that no ventral mesocardium exists, though in more lowly vertebrates it is present. ”

“ Such hearts always show increase in thickness of the ventricular wall. I quite agree with Stone, [8] who says, "It is merely to be emphasized that when the pulse pressure persistently equals the diastolic pressure (high pressure pulse, in other words) with a resulting 50 per cent, overload, which means the expenditure of double the normal amount of kinetic energy on the part of the heart muscle, cardiac hypertrophy has occurred." They are found in aortic insufficiency, in chronic nephritis, in the diffuse fibrous type of arteriosclerosis, and in some cases of exophthalmic goiter. ”

“ 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. ”

“ Observe whether there are any adhesions between the two surfaces of the pericardium. White patches are often seen on the visceral surface of the pericardium, especially over the ventricles. These have no pathological significance and are due to slight thickenings of the pericardium.
The Heart.—Having passed the hand over the arch of the aorta and noticed whether there is any evidence of aneurism or dilatation, we grasp the heart firmly by the apex, raising and drawing it forward. ”

“ The heart muscle sometimes becomes inflamed as a complication or result of the existence of general or febrile and of infectious diseases. Severe influenza or infectious pneumonia is not infrequently followed by myocarditis. By extension of inflammation of the endocardium or pericardium the muscle of the heart may become involved. Overexertion or especially hard work continued for a long time may cause this muscle to become inflamed. ”

“ But if an altitude of from four thousand to five thousand feet above the sea level puts a certain amount of strain on a normal heart and by a rise of the blood-pressure indirectly also on the small peripheral arteries, must not this action be multiplied in the case of a heart suffering from even an early stage of myocarditis or in the case of arteries with thickened or even calcified walls? ”

“ 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. ”

“ Again, there are all the physical evidences of an old organic affection of the heart, or those of acute endocarditis or pericarditis, and rapidly all the symptoms referable to the heart become greatly increased, whilst orthopnoea, pallor, and coldness of the extremities take place. If a careful examination of the chest reveals no intercurrent and pulmonary nor superadded cardiac affection, we may then fairly assume the existence of an intra-cardiac concretion. ”

“ The consistence is increased in atrophy, fibroid heart, chronic interstitial myocarditis, syphilis, etc. Cloudy swelling and fatty degeneration make the heart muscle softer and more friable. In postmortem decomposition the heart as a whole becomes soft. ”

“ The heart walls are similarly weakened and yield more readily to the internal blood pressure in endocarditis, myocarditis, pericarditis, high fever, infectious diseases, poisonings, anæmia, and debilitating diseases generally. Debility and incapacity to resist the blood pressure is the essential prerequisite to dilatation. ”

“ If the left ventricle becomes sufficiently weakened or dilated, the same damming back of the blood through the lungs and right heart occurs, and more or less serious signs of broken compensation develop. The main danger, however, with a heart with this lesion, occurring coincidently with arteriosclerosis, is a progressive chronic myocarditis. ”