Page images
PDF
EPUB

hering pericardium, it may be, or mal-position of the heart. The causes of hypertrophy may, therefore, be situated within the heart itself, or without and beyond it; but in all those cases in which the effect of the hinderance or obstacle is to detain the blood in one or more chambers, the hypertrophy will be likely to be accompanied by dilatation, and generally speaking the hypertrophy and dilatation result from disease in some part, which lies beyond the affected chamber in the order of the circulation." The largest hypertrophied heart, however, which we have met with, was one of the latter class, in which no such obstacle could be discovered. The specimen, which was taken from a middle-aged man, is preserved in the St. George's Hospital Museum, and weighed, when removed from the body, 5 lbs.; the left ventricle is enormously hypertrophied, and very much dilated at the same time; but beyond this increase in the size of the heart, no morbid appearances are perceptible or on record; the valves are all perfectly healthy.

Insufficiency of the valves, by whatever cause produced, is one of the most frequent excitements of hypertrophy; and as the former lesion prevails most on the left side, it agrees with the fact that the left ventricle is the part most commonly affected. Indirectly, the passage of the blood from the right side may be thus influenced, and an increase of the walls of that part result. Impediments occurring in the course of the arterial system at a greater or less distance from the heart act in a similar manner, but, as may be supposed, in the ratio of their proximity to the heart. It is thus that we account for the complication of hypertrophy, more especially of the left ventricle, with aneurisms. Obstructions in the capillary circulation, though less frequently, give rise to hypertrophy; this cause is found to obtain chiefly on the right side of the heart, partly, we may fairly conclude, on account of the greater vicinity of an extensive capillary system in the lungs to this portion of the organ than exists in relation to the systemic side. The most marked case of hypertrophy of the right ventricle which we ourselves have witnessed, occurred in a child of one year and a half, who had been long subject to pneumonic attacks; and in whom, after death, the whole of both lungs were found studded with small lobular abscesses. The substance of the right ventricle was increased in thickness by one-third, as compared with the left ventricle. An undeniable influence must be also attributed to inflammatory affections of the endo and exo-cardium, as well as to chronic inflammatory conditions of the muscular tissue of the heart; though the actual demonstration of the latter is a point yet to be effected, unless we assume that fatty degeneration may be the result of a phlogistic process. The manner in which pericarditis gives rise to it, is by causing partial or general adhesions, and thus preventing the free contraction of the muscular tissue. Endocarditis most commonly gives rise to hypertrophy, by inducing changes in the valvular apparatus, and thus affording impediments to the sanguineous current.

In the thirty-fifth volume of the Medico-Chirurgical Transactions, Dr. Barclay publishes a list of ninety-two cases of heart disease, taken from the post-mortem records of St. George's Hospital, of which we have made an analysis with regard to the relation of frequency of hyper

trophy and dilatation; and we find that while the muscular tissue of the heart presented a state of hypertrophy only in twelve cases, there was hypertrophy combined with dilatation in forty-six, and only fourteen in which the latter condition was observed alone.

DILATATION OF THE HEART.

If in hypertrophy of the heart we in many cases see an effort of nature to adapt the organ to peculiar requirements entailed upon it by morbid conditions, and therefore would, à priori, expect to find it frequently accompanied by dilatation, we fail to discover this tendency where the latter condition occurs by itself. This form of dilatation is necessarily associated with an attenuated state of the muscular parietes, and may, therefore, be considered as synonymous with atrophy of the organ. Hypertrophy, with dilatation, corresponds to the condition to which the older authors applied the term active dilatation; while dilatation, associated with a diminution of the fleshy parietes, was known as passive dilatation. The two conditions have also been respectively called, by Corvisart, active and passive aneurism of the heart. These various terms show that the subject itself has not been established on a settled basis; and they certainly only tend to increase the embarrassment of the student. The less our nomenclature involves disputed theories the better, and as long as we are unable to base our terminology upon a knowledge of the proximate causes of disease, it is wiser to employ names that are derived from the most prominent symptom. In the present instance, we shall continue to use the term dilatation to designate a distinct class of morbid changes in the heart, and we shall separately consider the two varieties under which it occurs, the general and the partial form.

When, as Bouillaud remarks, the blood ceases to exert its stimulant and irritant influence upon the heart, and there are causes tending to enlarge its cavities, we find dilatation without hypertrophy; the blood in that case does not augment the molecular nutrition of the organ, but appears to act simply according to the laws of hydrostatics as a forcing power. That it should, however, at any time be able to cause a change in the cardiac cavities, necessarily presupposes an alteration in the power of the heart, and in the cohesion of the muscular tissue. The ultimate cause of these conditions may be supposed to reside in the nervous or vascular system, or in both conjointly.

The parietes of a dilated heart may be attenuated to an extreme degree; the thickest part of the left ventricle may be reduced to two lines. in diameter, while at the apex the muscular substance may have disappeared entirely, so that the endocardium and pericardium are in opposition; at the same time, we find a corresponding diminution in the thickness of the columnæ carneæ. In one point there is a characteristic difference between hypertrophy and dilatation, independently of the nature of the lesion. This is in regard to the part affected. The left ventricle is most frequently attacked with hypertrophy, while we meet with dilatation most commonly in the right ventricle. It has been stated that the female sex are most prone to dilatation, and males to hypertro

phy; we do not find this to be the case. On analyzing the ninety-two cases of heart-disease collected and reported in the Medico-Chirurgical Transactions, by Dr. Barclay,' with a view to determining this question, we find that, of fourteen cases of dilatation, six occurred in females, and eight in males; of sixteen cases of hypertrophy alone, seven were women, and nine men; of forty-six cases of hypertrophy combined with dilatation, seventeen were females, and twenty-nine males. On a rough average it therefore appears that in each variety there is a preponderance of about one-third on the side of the latter. Dilatation, as Dr. Hope remarks, takes place more in the transverse than in the longitudinal direction of the ventricles, and it accordingly communicates to the heart an unusually spherical form, the apex being rounded off in such a manner as frequently to be scarcely distinguishable.

Dilatation affects the auricles more frequently than hypertrophy; however, we must be careful in not hastily assuming a diseased condition, where its semblance is owing merely to distension. This is particularly the case with the right auricle, which very commonly appears much dilated, owing to the accumulation of blood taking place on this side of the heart in articulo mortis. If on removing the contents the cavity presents its normal appearance, we consider it to have been merely mechanically and temporarily distended; if the enlargement is persistent, we may look upon it as the result of morbid action during life. A dilatation of the right side of the heart is met with in connection with patency of the foramen ovale. A case of this kind was exhibited by Dr. Lloyd, before the Pathological Society. It occurred in a boy aged sixteen, who had been subject to bronchitis, with temporary cyanosis. The right auricle was much dilated, and the right ventricle was dilated and hypertrophied, while the left side presented the normal appearances.

The preceding remarks apply mainly to general dilatation; partial dilatation, or aneurism of the heart, is, according to Rokitansky, whose views on this subject are particularly lucid, a condition depending especially upon an inflammatory state of the endocardium and the muscular tissue at the point affected. The following abridged view of this writer's opinions is the best account of the matter that we have to offer to our reader. Rokitansky assumes the existence of two distinct forms of cardiac aneurism. The first-the acute and rarer form-depends upon a laceration of the diseased endocardium, and adjoining muscular tissue, through which the blood passes; and the power of resistance being diminished at the point, a pouch is established, a fringed margin of endocardium is found at the entrance, and the blood deposits its fibrin within, while the margin becomes fringed with vegetations. Rokitansky has never seen a case in which the walls of an aneurism, formed in this manner, had become consolidated into a fibroid, callous tissue. In all the cases examined by him, the aneurismal formation was of recent date, having existed only a very inconsiderable period after the endocarditis, during the continuance of which it had originated. The second form

1 Medico-Chir. Transact. vol. xxxv.

2 Reports of Pathological Society, 1848, p. 223.

is the more remote effect of an inflammatory condition of the investing or lining membrane, or of the muscular parietes of the organ. This induces the development of a fibroid tissue, replacing, or, we should rather say, causing the absorption of, the muscular fibre. The new tissue contracts, the parietes lose their power of resisting the pressure of the blood, and a circumscribed dilatation ensues.

The aneurism varies much in size, from that of a pea to that of the heart itself; it does not necessarily present an enlargement at the surface, nor does it appear to possess an inherent tendency to increase; thus, in a case presented to the Pathological Society by Dr. Jenner,' in 1848, an aneurism was found of the size of a filbert at the apex of the left ventricle. Though there was no muscular substance over the extremity of the sac, it did not project beyond the external wall of the ventricle. The existence of the aneurism in this instance was traced back to two years previous to the death of the individual. A few old

[merged small][graphic]

Aneurism of the left ventricle, formed by dilatation of a circular portion of the anterior wall, in a girl aged 19. The pouch was filled with a laminated coagulum; its mouth was narrow, round, and smooth, and its parietes consisting apparently of endo and pericardium, with small deposits of a soft yellowish substance between them. The disease had probably commenced 18 months before death.-St. Bartholomew's Museum. Series xii. No. 53.

slight adhesions binding the apex of the ventricle loosely to the free pericardium, indicated a previous inflammatory condition at the affected point. It appears that the healthy tissue of the organ possesses in many instances an inherent power of neutralizing the evil effects which might be expected to result from a local loss of resisting power in the parietes; otherwise, it is difficult to understand how a cavity can be hollowed out in their substance without seriously impairing the contractile power. We sometimes find cases in which the thinning is not quite so definitely circumscribed as Rokitansky describes it, and where it yet proceeds to an extreme degree. Thus, we have seen a case of enormous dilatation of both ventricles without hypertrophy, in which the apex of the left ventricle was thinned to the size of a sixpence (St.

Report of the Pathological Society, 1848-9, p. 89.

George's Museum, 1842-62). Partial aneurisms are not necessarily solitary, but there may be two or three, which may, as they progress, intercommunicate. Next to the apex of the left ventricle we find its base, and, third in order, the septum ventriculorum liable to be thus affected; in the latter case the bulging is towards the right side of the heart. Considering that there is a point in the upper part of the.septum, at which normally there is no muscular tissue to maintain the separation of the two cavities, we should be led to expect the occurrence of aneurism more frequently at this point; but in ordinary circumstances the balance of the circulation suffices to prevent this result. When this form of aneurismal dilatation extends to such a degree that an opening and communication between the ventricles results, we have to deal with what Dr. Thurnam has termed the varicose aneurism; it is a condition analogous to a congenital state, not unfrequently met with, in which the ventricular septum is more or less defective.

The contents of the cardiac aneurisms vary; we find in them fluid blood, more or less decolorized, sanguineous coagula, or laminated fibrinous deposits, resembling those found in arterial aneurisms, and presenting similar microscopic appearances.

The male sex and mature age offer a greater proneness to aneurism of the heart than the female sex and youth; the proportion with regard to sex is about 1 to 3; Hasse states that of forty-seven cases thirty-five were men and twelve women; and of forty-two cases, ten referred to individuals under thirty, and thirty-two to older persons.

ATROPHY OF THE HEART.

In introducing the subject of dilatation, we observed that it was essentially an atrophic condition. Atrophy of the heart is also met with in the shape of a mere reduction of size, either as a result of wasting disease or as a congenital vice. Three extreme cases recorded by Burns probably belong to the latter variety; in one instance, he found the heart of an adult as small as that of a new-born infant, and in another the heart of a female, aged six-and-twenty, was no larger than of a child of six years. Bouillaud describes a case of an old woman of sixty-one minutely, who died of acute peritonitis, in whom the heart was a third smaller than in the normal condition, or about the size of the heart in a child of ten or twelve. The surface was furrowed and presented milk spots, the remains of former pericarditis; the cavity of the left ventricle was scarce large enough to contain a pigeon's egg, its parietes were only three lines in thickness. In phthisis, there is a uniform diminution in the size of the heart; in no other maladies is this so much the case, as illustrated by the following measurements given by Bizot' of the heart in the adult:

1 Mémoires de la Société d'Observation, vol. i. p. 277.

and

« PreviousContinue »