Cardiac hypertrophy

“ Longcope and McClintock, however, conclude that permanent constriction of the superior mesenteric artery and celiac axis, as well as gradual occlusion of one or both of these vessels, may be present in dogs for at least five months without giving rise to definite and constant elevation of blood pressure or to hypertrophy of the heart. Further, they have been unable to find at autopsy on man a definite association between sclerosis of the abdominal aorta and great splanchnic vessels and cardiac hypertrophy. ”

“ 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. ”

“ 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. ”

“ Abnormal vasodilatation seriously interferes with the normal circulation, and causes venous congestion, abnormal increase in venous blood pressure, and the consequent danger of shock and death. Increased arterial tone or tonicity necessitates greater cardiac effort, to overcome the resistance, and hypertrophy of the heart must follow. This hypertrophy always occurs if the peripheral resistance is not suddenly too great or too rapidly acquired. In other words, if the peripheral resistance gradually increases, the left ventricle hypertrophies, and remains for a long time sufficient. ”

“ Bollinger and Schmidbauer have shown that the habitual consumption of beer in excessive quantities leads to cardiac hypertrophy of characteristic form. Both sides of the heart participate in the overgrowth: there is enormous increase in the volume of the primitive muscular elements, with enlargement of the nuclei. Whether or not actual numerical increase in the muscular fibres takes place cannot be determined. ”

“ Actual enlargement of the organ may, however, result from prolonged over-action, as in Basedow's disease, in the smoker's heart, and the irritable heart of neurasthenics, but it is usually slight. Increased dulness in the cardiac area may be due to a variety of causes, some of which may simulate hypertrophy, as pericardial effusion, aneurism, mediastinal growths, or displacement of the heart from pressure or the existence of malformation of the chest; but with the exercise of ordinary care the diagnosis can usually be made. There are two opposite conditions which not infrequently give trouble. ”

“ It is often difficult to determine whether an endocardial murmur is of old or recent origin: if during an attack of acute rheumatism an endocardial murmur is developed under daily examination, it is a certain index of acute exudative endocarditis. If a murmur exists at the first examination which is systolic, soft, and blowing in character, and not accompanied by the evidences of cardiac hypertrophy, there is good reason to believe that it is produced by an acute endocardial inflammation. ”

“ Hypertrophy of both ventricles increases the length and breadth of the heart. Hypertrophy of the left ventricle alone increases its length; of the right ventricle alone increases its breadth toward the right side. Hypertrophy with dilatation may affect the chambers of the heart conjointly or separately. This form is by far the most frequent variety of cardiac enlargement. When the entire heart is affected, it assumes a globular appearance, the apex being almost obliterated and situated transversely in the chest. The bulk may become three or four times greater than the average heart. ”

“ For long periods of years the effects of mitral stenosis may be counterbalanced completely, and only sudden death by accident or an acute disease reveals the existence of extensive unsuspected heart disease. In the hypertrophy secondary to pulmonary disease, particularly emphysema and cirrhosis, there may be sensations of uneasiness in the cardiac region, with cough and shortness of breath; but so long as the dilatation is moderate the symptoms are not marked. With great dilatation and tricuspid regurgitation come the venous engorgement, oedema, and pulmonary troubles. ”

“ In such young girls we have very frequently found tight stays, which were worn unchanged without regard to the growth of the body in length, and which, by pressure on the epigastric region, elevation of the diaphragm, and limitation of the respiratory movements of the thorax, actually offered such considerable resistances to the driving power of the heart, as ultimately to lead to hypertrophy of the cardiac muscle. ”

“ 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. ”

“ Chronic valve disease is thus found to be a common result of endocarditis, and from the obstacle presented to the flow of blood through the different cardiac orifices by the rigid, inelastic and distorted valves, hypertrophy of the heart frequently supervenes. ”

“ Serum may accumulate in the pericardium, owing to an obstruction of the cardiac veins, caused by hypertrophy of the substance of the heart; and when from this cause the pericardium becomes much distended with fluid, the pressure of this upon the flaccid auricles and large venous trunks may give rise to general anasarca, to hydrothorax or ascites, either separate or co-existing. Tuberculous deposits in the lungs and scrofulous bronchial glands may cause obstructive pressure on the pulmonary veins, followed by effusion of either pus or serum into the pleural sac. ”

“ He was able to confirm the existence of hypertrophy by autopsy. It is not uncommon to meet with cases of pronounced heart disease, with symptoms of failing compensation, dropsy, etc., in large, powerfully-built men who have been engaged in laborious occupations, and who are admitted to hospital with the clinical picture of chronic valvular disease. At the autopsy one is surprised to find an hypertrophied and dilated heart without valve lesion, perhaps no extensive arterial degeneration, and no kidney disease. ”

“ To hypertrophy properly the heart must go into training. This training is necessary in valvular lesions after acute endocarditis or myocarditis, and is the reason that the return to work must be so carefully graduated. When the heart is hypertrophied sufficiently and compensation is perfect, a reserve power must be developed by such exercise as represented by the Nauheim, Oertel or Schott methods. Anything that increases the peripheral resistance causes the left ventricle to hypertrophy. Anything that increases the resistance in the lungs causes the right ventricle to hypertrophy. ”

“ After careful inspection has given all the data which it is possible to obtain, one next lays the palm of the hand over the heart and attempts to palpate the apex beat. The thrust of the apex in a hypertrophied heart can readily be felt, and one can feel whether the heart is regular, irregular, intermittent, or has other change in rhythm. The shock of the closing valves, particularly the aortic, can be felt, and that and the forcible apical impulse are very suggestive signs of hypertrophy and hypertension. ”

“ Striking cyanosis is an early symptom, while there is little if any dyspnea and edema. Intermittent dyspragia is common. There seems to be no tendency to clubbed fingers. Repeated hemorrhages from the lungs without the formation of infarcts may occur. There is usually an area of dullness at the upper left margin of the sternum and nearby parts, sensitive to pressure and to percussion, and the heart dullness extends unusually far towards the right. The diagnosis of the right ventricular hypertrophy may be substantiated by a fluoroscopic examination. ”

“ No better example of this can be seen than in the case of certain forms of heart disease, where from defect at some of the natural orifices of that organ the onward flow of the blood is interfered with, and would soon give rise to serious embarrassment to the circulation, were it not that behind the seat of obstruction the heart gradually becomes hypertrophied, and thus acquires greater propelling power to overcome the resistance in front. ”

“ As long as the heart remains in this hypertrophied condition, which may be called normal hypertrophy since it is needed for the work which has to be done in overcoming the defect in the valve, there are no symptoms, the pulmonary and systemic circulation is sufficient, and the patient does not know that he is incapacitated. ”

“ In hyperthyroidism at first the blood pressure may be lowered on account of the increased physiologic secretion of the thyroid gland. Later the blood pressure may be raised by stimulation of the suprarenals, or it may become raised from the irritated and stimulated heart becoming hypertrophied. If the heart is normal the ventricles should hypertrophy with the increased work that they are under; and the blood pressure could increase for this reason. Later in exophthalmic goiter the heart muscle may become degenerated, a chronic myocarditis, and the ventricles may slightly dilate. ”

“ 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. ”

“ So admirable is the adjusting power of the heart that, for example, an advancing stenosis of aortic or mitral orifice may be for years perfectly counterbalanced by a progressive hypertrophy, and the subject of the affection be happily oblivious to the existence of heart trouble. Particularly is this the case with mitral stenosis and the consequent hypertrophy of the left auricle and right ventricle. While leading quiet lives and not straining the heart with violent exertion, such persons may not suffer in any way, or perhaps only experience a little shortness of breath when going up stairs. ”

“ Pericardial adhesions, particularly when in addition to union of the layers the parietal membrane is firmly united to the pleura or to the sternum, may cause hypertrophy of the left ventricle alone, but more commonly of the whole heart. ”

“ In addition to these symptoms there is sometimes, as Becker has pointed out, a dilatation of the arteries, which may almost equal the veins in calibre. At times there is an arterial pulse. As found by autopsies, the anatomical changes are usually enlargement and dilatation of the heart, hypertrophy and various degenerative changes in the thyroid glands, and a state of hyperæmia at times associated with hypertrophy of the fat tissue of both orbits. ”

“ As a consequence of the enfeebled action of the heart, the arteries are not well filled during the systole, and there is anæmia of the organs. The mural weakness readily permits of dilatation, with imperfect emptying of the chambers and distension of the venous system. In hypertrophy the failing compensation is frequently due to the onset of fatty degeneration. During a sudden strain or a more continued effort than usual there may be heart failure, asystolism, or the walls may tear and sudden death occur from rupture. ”

“ Mental emotions, severe grief, or fright have been known to bring on symptoms of heart failure in hypertrophy. One of the most frequent causes is sudden or prolonged muscular exertion, which may disturb a compensation perfect for years, and induce death in a few days.59 The intimate pathology of broken compensation is not always clear. It certainly does not always depend on degeneration of the muscle-fibres, so far as microscopical examination can tell, and in many cases we are forced to conclude that the ganglia are at fault and the breakdown is nervous, not muscular. ”

“ Dropsy of the pericardium will give the same wide space of dullness, but the impulse and sound are lessened. An animal with a moderate degree of enlargement may possibly live a number of years and be capable of ordinary work; it depends largely upon concomitant disease. As a rule, an animal affected with hypertrophy of the heart will soon be incapacitated for work, and becomes useless and incurable. ”

“ Of the other conditions of malformation, narrowing of the aorta and of the aortic conus seems to be, on the whole, compatible with a longer duration of life than any other condition, and these defects cause death in the early days or months in fewer cases than similar obstructions on the right side of the heart. This result apparently comes from the fact that the left ventricle seems to possess unlimited capacity for hypertrophy, and hence is able to overcome the obstruction; when the aortic valves allow of regurgitation the compensation fails and death comes sooner. ”