Definition of Enlargement by Dilatation – Symptoms – Pathological Effects – Physical Signs and Diagnosis – Summary – Treatment.
GENTLEMEN: In this lecture, a condition of the heart nearly the opposite of that described in the last, namely, enlargement by dilatation, will be considered. I shall quote entire Flint’ admirable description, because no words of mine could make it plainer. The treatment, however, is purely homoeopathic – not theoretical, but based on experience.
“Under this head are embraced, in addition to the rare cases of pure or simple dilatation, that is, those in which the capacity of the cavities is increased and the walls attenuated, all cases in which dilatation co-exists with, but predominates over hypertrophy. Of the two kinds of enlargement, this is by far the most frequently found after death when organic disease of the heart proves fatal. In the cases in which the heart attains to a very large size, dilatation almost invariably preponderates. The cases in which the organ, from its immense bulk, resembles a bullock’s heart (corbovinum) are those in which there exists great hypertrophy, with still greater dilatation. The degree of dilatation varies greatly in different cases, and the hypertrophy combined with it is also variable. The preponderance of dilatation, when the heart is examined after death, is generally sufficiently evident on inspection. The abnormal increase in the dimensions of the organ exceeds that of the weight. The ventricular walls collapse, and the organ, resting on its posterior surface, is flattened, instead of preserving a globular form, as when hypertrophy predominates. The greater increase in width than in length, is marked in proportion to the preponderance of dilatation. Owing to this, the organ becomes wedge-shaped, and sometimes presents nearly a square form.
“The mechanism of dilatation is quite different from that of hypertrophy. In the production of the latter the process is vital, whereas in the former it is mechanical. Hypertrophy is a consequence of over-nutrition; dilatation is the result of the yielding of the walls of the heart to a distending force, the condition, however, which stands immediately in a causative relation to both is the same, viz., undue accumulation of blood within the cavities of the heart; hence it is that both take place either conjointly or in succession, so that hypertrophy and dilatation are very often associated. Dilatation, thus, not less than hypertrophy, depends on antecedent affections which occasion impediment to the circulation through the vessels or the orifices of the heart, leading to over-accumulation of blood within the cavities. These antecedent affections are the same as in cases of predominant hypertrophy; and the several portions of the heart become affected singly and in succession, as in the latter form of enlargement. It is not necessary, therefore, in this connection, to consider the dilatation of these portions, respectively, in relation to the particular lesions of the valves and orifices and vessels on which dilatation and hypertrophy alike depend. Moreover, both dilatation and hypertrophy of the different portions of the heart will be referred to hereafter in treating of valvular lesions. It will suffice to inquire into the circumstances which determine the occurrence of dilatation in the place of, or, as is generally the case, in addition to, hypertrophy.
“The first effect of an undue accumulation of blood in the cavities of the heart, continued for a sufficient period, is increased power of muscular action and consequent hypertrophy in the great majority of cases. The hypertrophy is more or less progressive, but it has its limit. The abnormal growth of the muscular tissue ceases after it has progressed to a certain extent. But the morbid conditions inducing over-repletion of the cavities still remain, impending more and more the circulation. The compensating increase of the muscular tissue no longer taking place, the walls of the cavities yield to the mechanical force of distension, and the progressive enlargement from this time onward is due to dilatation. The limit of hypertrophic enlargement varies in different persons. If the hypertrophy progress until the muscular walls attain to a great thickness, and life continue for a long period afterward, dilatation finally predominates, and the result is an enormous enlargement of the heart, a cor bovinum. But dilatation may commence after moderate or slight hypertrophy has taken place; in other words, the hypertrophy ceases after a smaller amount of muscular growth, and dilatation commences. Dilatation may even commence without any previous hypertrophy, and the result is, then, enlargement with attenuated walls, or simple dilatation, a rare variety of enlargement of the heart. The occurrence of dilatation is determined by the state of the muscular walls. Functional debility of the organ, and, still more, changes in the muscular fibres, prevent that vigorous activity which induces abnormal growth; and yielding of the walls takes place early, in proportion as the vital power of resistance is impaired. Anaemia, the feebleness consequent on pericarditis and adherent pericardium, fatty degeneration, softening, and any changes which compromise the muscular power of the organ, tend to abridge hypertrophy and favor dilatation. The latter will therefore predominate in proportion as the condition of the walls in such that they early and readily yield to the distension caused by the accumulation of blood within the cavities. After this brief consideration of the circumstances determining the occurrence of dilatation, in addition to the incidental remarks already made under the head of enlargement by hypertrophy, the reader will be able to trace the relations of dilatation affecting the different cavities of the heart, to lesions of the mitral and the aortic orifice, involving either obstruction or regurgitation, or both, and to obstructions affecting the pulmonary and systemic arterial system at situations more or less remote from the heart, without recapitulation of the account already given in connection with hypertrophy. The inquiry arises, Does not the heart, in some instances, become dilated in consequence of inherent weakness, no antecedent affections existing to occasion impediment to the circulation? It is probable that this sometimes occurs as an effect of fatty degeneration, pericardial adhesions, atrophy or softening of the muscular fibres, etc. Examples are found of dilatation associated with these structural changes, and without other obvious sources of impediment to the circulation. These changes may be subsequent to dilatation, but it is reasonable to suppose that in some instances they precede and give rise to it. Clinical observation, however, furnishes no evidence that functional weakness alone leads to dilatation, irrespective of structural changes of the walls of the heart, or lesions of some kind which occasion impediment to the circulation. Dr. W. T. Gairdner accounts for dilatation of the heart in cases of pulmonary emphysema, in the same way that he accounts for emphysema, namely, the cavities of the heart are dilated by the force of inspiration, as are the unobstructed air-cells in consequence of collapse of more or less of the pulmonary lobules. this author accounts in this way for, not only dilatation, but hypertrophy, the expansion of the thorax tending constantly to overload the heart, and thus occasioning increased muscular force. Without adopting this explanation, it must be admitted that Dr. Gairdner bases his explanation on facts which have considerable weight. Of 24 cases of enlargement without valvular lesion, in 21 cases there were manifest and extensive old atrophic lesions of the lungs, with or without accompanying emphysema, which is recorded as having existed in 17 of the cases.” Dr. Gairdner also shows, by an analysis of fatal cases, that enlargement of the heart occurs oftener in emphysematous cases than in mixed cases, the proportion being as 15 to 23 per cent.; and that, of the cases occurring with emphysema, valvular lesions are present in a less proportion than in the mixed cases, the whole number of cases analyzed being 84. To show that contraction of the capillaries of the lungs from any cause, or obstructed circulation through these organs, will not give rise to enlargement of the heart, he analyzes 18 cases, in which effusion into the pleurae or peritoneum, or other causes, occasioned compression of the lungs for a considerable time, there being no valvular lesions. In only four of these cases did enlargement exist, and in one case its existence was doubtful. On these data he bases the conclusion, that, while diseases of the lungs which merely obstruct or obliterate the circulation in the capillaries, have no well-marked tendency to be associated with enlargement of the heart, those which produce atrophy of the pulmonary tissue, and secondarily emphysema, have an obvious influence on the heart, and frequently cause its enlargement.
SYMPTOMS AND PATHOLOGICAL EFFECTS OF DILATATION.
“The symptoms due to dilatation, like those of hypertrophy, are generally involved with those incident of valvular or other concomitant lesions. In proportion to the amount of dilatation, the muscular power of the heart is impaired. The symptoms distinctive of dilatation proceed from feebleness and incompleteness of the heart’s action. The action of the heart is often irregular, as represented by irregularity of the pulse and of the apex-beats. Both are abnormally feeble. The pulse may be unequal as well as irregular. These symptoms are in relation to dilatation of the left ventricle. The patient experiences more or less uneasiness and undefinable distress, referable to the praecordia, but he is not conscious of that powerful action of the heart which characterizes hypertrophy. The extremities and surface of the body are cool. Lividity may be apparent on the prolabia, the tongue, face, and extremities. the veins, especially those of the neck, may be distended. These symptoms are more or less marked, in proportion as the dilatation affects the right ventricle. Dyspnoea will be prominent in proportion as the right ventricle is the seat of dilatation. The recumbent posture, with the head low, may be insupportable, and, in an advanced stage, the suffering from defective haematosis may amount of orthopnoea. Occurring in paroxysms, this difficulty of respiration has been called cardiac asthma. Exercise and mental excitement augment the symptoms, particularly the dyspnoea. More or less cough is usually present, with serous and sometimes sanguinolent expectoration. The abdominal viscera as well as the lungs, are in a state of passive congestion. Owing to this state, the liver may become more or less enlarged, and may be found to augment rapidly in size when, from any cause, the circulation is temporarily embarrassed in an unusual degree, resuming it former dimensions when the paroxysm ends and the heart recovers its habitual strength.* * Strokes on the Heart and Aorta. The digestive functions are weakened, but nutrition may be sufficiently active; patients do not always emaciate. The urine is not abundant, and may be found slightly albuminous, which is due to renal congestion, and is not necessarily indicative of structural disease of the kidneys. Renal disease is, however, associated, in a certain proportion of cases, with dilatation as with hypertrophy. Finally, oedema occurs, first manifested in the lower extremities, thence extending over the body, and effusion into the serous cavities, succeeds, constituting general dropsy.
“This is an enumeration of the more important of the symptoms belonging to cases of enlargement in which dilatation predominates, but it is to be borne in mind that, in general, valvular or other lesions co-exist, which, after inducing more or less hypertrophy, have at length led to dilatation; and, under these circumstances, it is difficult to say to what extent the symptoms distinctive of this stage of the disease may not be due to the causes of the dilatation, in other words, to the concomitant lesions. But it is certain that much, if not chief importance is to be attached to the dilatation in the production of the symptomatic phenomena which have been mentioned.
“The pathological effects of dilatation are, in a great measure, embraced in the foregoing account of the symptoms. The dilatation is the result of weakness of the cardiac walls, together with an accumulation of blood within the cavities; and, on the other hand, it is the cause of further diminution of the power of the heart’s action, and consequent over-repletion. It has, therefore, an intrinsic tendency to increase. The evils incident to enlargement are mostly referable to dilatation. Little or no inconvenience is felt so long as the heart is hypertrophied, and the capacity of its cavities not increased. But in proportion as the latter takes place, the quantity of blood to be propelled from the cavities is greater, and the ability of the muscular walls to contract sufficiently is lessened; hence, inadequacy of the motive power of the central organ to carry on the circulation. This inadequacy increases in more than an arithmetical ratio as the dilatation progresses. The immediate effect on the vascular system is passive congestion, arising, not alone from the defective propelling power of the heart, but from the obstacle presented to the return of blood to this organ by the accumulation within its cavities. The ulterior effects dependent on congestion are: embarrassment of the functions of the important organs of the body; serous transudation, or dropsy; and, occasionally, haemorrhage. An occasional effect of great dilatation, conjoined with extreme feebleness of the heart’s action, is the formation of coagula within the cavities of the heart. There is reason to believe, that in some instances in which the accumulation is excessive, and the contraction of the walls extremely feeble, the blood coagulates during life, and proves the immediate cause of a fatal termination. An unusual accumulation of blood, from any cause, in either the right or the left ventricle, when it is much weakened by dilatation, may occasion paralysis of the walls by distension, and thus produce sudden death.
PHYSICAL SIGNS DISTINCTIVE OF ENLARGEMENT BY DILATATION.
“The physical signs of enlargement of the heart have been already fully considered. The signs distinctive of dilatation are now to be noticed. The several methods of exploration which furnish evidence of enlargement, contribute signs pointing to dilatation in distinction from hypertrophy. The evidence obtained from percussion relates to the form of the area of deep dullness. If the boundaries of the heart be delineated on the chest by means of percussion, the transverse dimension of the area exceeds the vertical in proportion as dilatation predominates over hypertrophy. This corresponds to the difference as regards the form of the heart, which has been stated. The outline which the heart presents is wedge-shaped or nearly square if the dilatation be excessive. Palpation furnishes negative characters more readily available and striking. The powerful apex-beat of hypertrophy is wanting; also the elevation of the ribs and the heaving of the praecordia. The impulse of the apex is feeble, and may be suppressed. The movements of the organ, owing to the extended space in which it is in contact with the thoracic walls, are sometimes obscurely felt, and oftener visible in two, three, four, or even more intercostal spaces, which together present an appearance of fluctuation, or, as called by Walshe, quasi undulation. In some cases, in which the thoracic walls are thin, and the intercostal spaces wide, the heart seems to be almost exposed to the vision and touch. Auscultation furnishes certain distinctive points pertaining to the heart-sounds. Both sounds are feeble in comparison with their augmented intensity in cases of hypertrophy, but the first sound is disproportionately wakened. The first sound is also altered in character; it becomes short and valvular, resembling in these respects the second sound. The latter alterations, although distinctive of dilatation as contrasted with hypertrophy, are not peculiar to the former, and their true explanation has not been understood. They are due to the impairment or absence of the element of impulsion in the first sound. This element is deficient or wanting whenever the left ventricle lacks the muscular power necessary for its production. In hypertrophy this element is intensified, owing to the increased force of the ventricular contractions; and in dilatation it is feeble or absent, owing to the feebleness which, at the same time, renders the apex-beat weak or inappreciable. But this element is also impaired or absent when, from other causes than dilatation, the muscular power of the heart is weakened. The intensity of the first sound is diminished disproportionately to that of the second sound, in cases of fatty degeneration, and of softening in typhus fever, and of pericarditis with effusion. The valvular element predominates, or is alone present in consequence of the feebleness or absence of the element of impulsion. But the intensity of the valvular element is also more or less diminished, in the first place, in consequence of the weakness of the ventricular contractions, and in the second place, because at the time when the ventricular contractions take place, the quantity of blood within the ventricle is large, causing closure of the auriculo-ventricular valves.
“In the diagnosis of enlargement by dilatation, assuming the fact of enlargement to have been ascertained, symptoms (as distinguished from signs) have considerable weight. Passive congestions, lividity, feeble pulse, and dropsical effusion, in fact, constitute evidence almost, if not quite conclusive. The obstruction due to the valvular lesions which are so generally associated with enlargement, it is true, contributes toward the production of these symptoms; but, as will be seen when valvular lesions are considered, the obstruction due to these rarely, if ever, gives rise to the effects just mentioned until dilatation of the cavities of the heart has taken place. With the aid of the physical signs, the discrimination between predominant dilatation and predominant hypertrophy may generally be made with reference to prognosis and treatment. The prospect of life and tolerable health is less in proportion as dilatation predominates, and the management involves attention to incidental events which do not occur as long as hypertrophy predominates. For the convenience of comparison with the physical signs distinctive of hypertrophy (see page 149), the signs distinctive of dilatation are embraced in the following summary:
SUMMARY OF THE PHYSICAL SIGNS DISTINCTIVE OF ENLARGEMENT BY DILATATION.
“1. Percussion. – The transverse dimensions of the space occupied by the heart greatly exceeding the vertical, the form of this space corresponding to the wedge-like or square form of the organ when the dilatation is excessive.
“2. Palpation. – The apex-beat devoid of abnormal force, and in some instances suppressed. Absence of heaving movement of the ribs and praecordia.
“3. Auscultation. – The element of impulsion of the first sound deficient or absent, and the sound short and valvular; in these respects resembling the second sound.”
TREATMENT OF DILATATION.
The indications for the treatment of enlargement by dilatation in some respects does not differ from the treatment of predominant hypertrophy. In other and important respects, however, the treatment materially differs.
You cannot remove the impediment to the circulation which co- exists in the great majority of cases, but the effects may be mitigated, if you have your patients avoid the extrinsic causes which excite unduly the action of the heart.
In the dark days of the history of medicine, incalculable evil was done, under the impression that the mass of blood must be diminished. Bloodletting was resorted to, giving temporary relief, but ending most disastrously, by causing anaemia and muscular atony, accompanied with excessive cardiac irritability. The same effect was produced by drenching patients with saline drugs, or the use of exhausting cathartics. When these were abandoned, the allopathic school resorted to large doses of aconite, antimony, and similar exhausting remedies, which only made the disease worse, by weakening the nervous and muscular power of the heart.
Before speaking of medicinal agents, I will give you the general rules which you should try to make your patients adopt. Excessive muscular exercise, mental excitement, or anything calculated to excite unduly the action of the heart, should be avoided.
The great end of the treatment, remember, is to increase the muscular power of the heart. The diet, therefore, should be as highly nutritious as possible, and the quantity of liquid ingesta as small as is compatible with comfort. A diet of solid, easily- digestible, animal food, with a careful admixture of nutritious vegetables, should be advised. At the same time advise the patient to avoid any articles that appear to digest with difficulty.
Indigestion, constipation, hepatic torpor, or inactivity of the lungs, must be removed as soon as discovered, and carefully guarded against. The mental condition of your patient will have much to do with his condition. Depression of spirits tend to aggravate the disease. You must encourage as much as possible; in order to prevent the gloomy forebodings which annoy and depress. You can do this conscientiously, for in the majority of cases under your care, you can safely encourage hope, not of a complete cure, perhaps, but of tolerable health for an indefinite period. The common notion that disease of the heart ends in sudden death is erroneous, and you should strive by the most positive assurances to remove this idea from the minds of your patients.
The medicines most useful in the treatment of dilatation have already been enumerated under the head of Enlargement by Hypertrophy. This, at first thought, may seem strange; but when you remember that all medicines have a double pathogenetic action, you can readily see that they will prove curative in opposite pathological conditions. You will observe this in the provings of all medicines, and also from the fact that a medicine is recommended for constipation and diarrhoea, spasm and paralysis, irritation and torpor.
I will, therefore, recapitulate the same classes I gave you in the previous lecture, but with the appropriate indications:
Class I. Includes medicines whose primary effect is to depress and weaken the muscular and nervous power of the heart, and give rise to conditions which would tend to cause dilatation; but whose secondary effects are similar to those conditions described in the last lecture.