_Morbid Anatomy of the Internal Lining Membrane of the Heart._
The membrane which lines the cavities of the heart is very liable
to disease, but not equally so in every part. Where it is thin
and transparent, and admits the colour and character of the
muscular structure upon which it is spread to be seen through it,
it is seldom found diseased; but where it is of a denser texture,
either in itself or from an admixture of other structures, whether
cellular or fibrous, with its own, it is frequently, and often
exclusively diseased. This latter character of a denser texture
belongs to it where it forms the tough white circles which surround
the apertures of communication between the auricles and ventricles;
also where it is reflected upon itself, and forms the loose
duplicatures of membrane, which are given off, as it were, from
the internal surface of the heart, either at the fibrous circles
intermediate between the auricles and ventricles, constituting the
tricuspid and the mitral valves, or at the commencement of the
pulmonary artery and aorta, constituting the semilunar valves.
It is remarkable how curiously disease is apt to limit itself to
the spaces just pointed out. Of the fibrous circle between the
auricle and ventricle, of the valves which originate from it, and
of the tendinous cords which connect the valves with the carneæ
columnæ, there will not be the smallest space free from disease;
but the disease will abruptly stop where the tendinous cords cease
and the carneæ columnæ begin[1].
The membrane, however, where it covers the fleshy columns of the
heart, is not exempt from the possibility of disease: but when
disease actually affects it, it has seldom originated there,
but has generally spread from other parts of the same membrane,
although (as we have just remarked) it is apt to stop short before
it reaches this.
Of the two sides of the heart, the membrane which lines the left is
unquestionably the more liable to disease. But my own observation
would never have led me to conclude that the membrane of the right
side was so far exempt as it is commonly thought to be. Speaking
from the best recollection I have of the specimens which have
fallen under my examination, I should say that, in one-third of the
cases where disease has been found on the left side, it has existed
on the right side also, and been essentially of the same character.
But there has been a remarkable difference in the extent to which
it has proceeded on each side respectively: while on the left it
has gone so far as to be the undoubted cause of death, on the
right, although essentially of the same character, it has been only
just beginning.
It very seldom happens that disease appertains to the lining of
the right cavities of the heart exclusively; and, where it affects
both, the disease in the right cavities is very seldom found in
advance of that in the left.
It should seem, indeed, according to the ordinary course of things,
that disease does not begin in the lining of the right cavities of
the heart, until it has already advanced to an extreme degree in
the left.
The internal lining of the heart, as well as of the arteries, is
often found to have become of a red colour. This redness, so well
known to all who are accustomed to examine dead bodies, used to be
regarded as a mere stain imparted to it by the colouring matter
of the blood after death. Yet a due consideration of various
circumstances connected with it will hardly warrant this conclusion.
It has been found whether the heart or artery be full or empty of
blood; and if blood be present it has been found, whether it is
liquid or clotted; and if it be clotted, whether it does or does
not retain its colouring matter. External temperature, and length
of time between the death of the patient and the dissection of his
body, have not made any difference in the frequency with which
this peculiar appearance occurs. Lastly, no artificial methods,
such as washing of any kind, can get rid of it; nor will inclosing
blood within an artery for any period produce it[2]. This simple
redness is sometimes seen universally in both sides of the heart
and throughout the whole arterial system, and sometimes in patches
only, of greater or less extent, whether in the arteries or in the
heart.
Now, when all these circumstances are considered, although in some
instances it may be a mere stain imparted by the colouring matter
of the blood after death, it is plainly impossible that it should
be of that nature in any large proportion of the numerous instances
in which it is found.
But if the appearance in question implies (as I believe it
generally does) a morbid condition, of what kind is that condition?
There are the same objections to considering mere redness as
equivalent to inflammation here as in the pericardium, or in any
other part of the body: here, as elsewhere, in one case it may
be the condition out of which inflammation is to spring; while in
another it may not be destined to give origin to any change in the
structure of the part beyond itself, and may itself constitute the
whole disease.
It appears to me, that this mere redness of the internal lining
of the heart and arteries has become a matter of undue perplexity
to pathologists, because they have laboured to infer from it
more than the simple fact itself will authorize. All I wish to
establish concerning it is, first, that it is not always (probably
very seldom) a mere stain imparted by the colouring matter of the
blood after death; secondly, that it alone does not constitute
inflammation.
It may not be improper to mention the circumstances under which
it has occurred to myself to find it. I have met with it most
frequently, and to the largest extent, in subjects whose previous
disease has produced a constant and habitual impediment to the
transmission of blood through the heart and through the lungs,
and that impediment has gone on increasing to the hour of their
death; also in those, whatever might have been the nature of
their disease, whose dissolution (I mean the actual process of
dying) has been tardy and agonizing, and marked by great labour of
respiration; in the apoplectic, for example, in whom, after sense
and consciousness were extinct, life had been protracted, with
stertorous breathing, for many days.
In such subjects the countenance, the lips, and the whole skin,
give evidence during life of blood pushed beyond the natural sphere
of the circulation, and detained in the extreme blood-vessels.
Hence it is obvious that the causes which have loaded and distended
the capillaries in every part of the body have had a like influence
upon the vasa vasorum.
I do not mean to say that I never met with this peculiar condition
of the heart and arteries under other circumstances, or that
other causes may not produce it; but that I am not acquainted
with it under any other with which, from frequent coincidence, it
has seemed to have a natural connexion, or which have afforded a
reasonable explanation of the phenomenon.
This condition of the heart and arteries, considered as
inflammation, has been assigned by some as the cause of fevers
of the more malignant kind. The frequency with which it has been
found in some particular epidemic, must have led to the conclusion.
But, however this may be, from my own observation, not restricting
myself to the fever of any particular season, but taking into
account all complaints called febrile, and belonging to all
seasons, also from the result of inquiry among medical men who
have had large acquaintance with morbid dissections, and from the
experience of those who have made this particular point a subject
of investigation (Laënnec and Andral) I venture to conclude that it
has no essential connexion with fevers of any kind, either as cause
or as effect.
On some occasions the internal membrane of the heart and arteries,
wherever it exhibits the appearance described, will allow itself to
be peeled off from the subjacent structure with the least possible
force; this facility of separation ceasing entirely beyond the
boundary of the red tinge.
Here unquestionably is further evidence of a diseased condition:
but of what nature? Most pathologists would consider this to be of
the nature of inflammation--and I believe justly.
There is indeed much difficulty in pronouncing upon the nature of
minuter changes of structure detected in the internal parts of the
body after death. We are obliged to arrive at conclusions by help
of analogies drawn from morbid processes, which we have watched in
their progress during life, upon the external surfaces; for during
life we have the functions and sensibilities of the part to aid us
in forming a right judgment concerning its disease. When, during
life, one tissue is separated from another, as the periosteum from
the bone, or the cuticle from the skin, or the mutual cohesion
between different tissues is sensibly weakened, we find it to be
owing to the intervention of serous fluid which does not belong to
their healthy state; and this, together with increased vascularity,
or redness and heat, and pain, is enough to bespeak the presence
of inflammation. All these conditions cannot remain after death.
Hence, if we desire to form positive opinions concerning much
which is unfolded by dissection, we must supply the defect by
analogy. Thus, whenever, in any part of the heart or arteries,
the cohesion between the internal membrane and the subjacent
structure is manifestly lessened, and the membrane is unusually red
at that part, we may regard these appearances as the vestiges of
inflammation, without thinking that we go too far in so regarding
them.
The internal lining of the heart and arteries is often found red
solely in the neighbourhood of ulcerated spaces, when there can be
no doubt concerning the existence of inflammatory action.
But the internal lining of the heart and arteries gives the most
unequivocal evidence of its inflammation when it is found of a deep
red colour, with coagulable lymph adhering to its surface. This
condition is represented, as it was found in the aorta, in one of
the beautiful plates, illustrative of the diseases of arteries, by
Mr. Hodgson[3]. And the same condition, in the heart, I have seen
in a preparation of Dr. Farre's, where lymph is deposited, upon the
circular zone, which forms the aperture of communication between
the left auricle and ventricle. These appearances denote the most
acute inflammation: they are, I suspect, very rarely met with. In
the few instances in which I have heard of them, they have been
found where death has taken place after short and severe suffering,
and with symptoms which characterize inflammation.
But the specimens of disease most frequently met with in the
internal lining of the heart, consist in an entire change of its
natural structure, and in the formation of new products upon it or
within it. Many of these, from the analogy of morbid actions in
other parts of the body, must be considered to result from chronic
inflammation.
In any of those situations which have been stated as especially
liable to disease, the membrane will become thick, tough,
inelastic, puckered and shrivelled; and cartilage or gristle, and
bone, will enter into its structure; excrescences will sprout out
from it, resembling warts and fungus; and it will become ruptured
and ulcerated.
Cartilaginous depositions are often found beneath the membrane
where it is single; or between its folds where it is double, in
the situation of the valves; and thus they seem rather to belong
to some structure contiguous to the membrane than to the membrane
itself. Such depositions will proceed to a considerable extent,
while the membrane still remains free from disease. From a valve,
which has been thick, opaque, and cartilaginous, I have seen the
membrane separated on both sides, and transparent; the opaque and
cartilaginous matter being left behind. Where, in cartilaginous
depositions, the lining of the heart has become puckered and
uneven on its surface, and the valves shortened and altered in
their shape, the membrane itself participates in the disease,
and is generally incapable of being separated from the subjacent
structure. But great thickening may take place in the situation of
the valves, from deposition of cartilage, without any unevenness
of their surface or alteration of their shape; and under these
circumstances the membrane itself you may expect to find hitherto
exempt from disease[4].
Osseous depositions are always, I believe, originally formed
beneath, or exterior to, the membrane, both in the heart and in
the arteries. There are two circumstances especially worthy of
remark in this process of ossification: sometimes it is a pure and
unmixed process: bone is formed, and nothing else. It is deposited
in minute granules, or little brittle scales, or in plates of a
larger size; and the intermediate spaces, whether in the heart or
arteries, preserve their natural and healthy appearance. At first,
these granules or scales, or plates of pure bone, are covered by a
delicate pellicle, which is in fact the internal membrane of the
heart or artery, separating them from the immediate contact of the
circulating blood. But in process of time, as they increase in
size, and become rough and unequal on their surface, they cause a
rupture of the internal membrane, and have now nothing to separate
them from the immediate contact of the blood[5].
Sometimes ossification is a mixed process, or rather, I suspect,
the result of another morbid process preceding it. With the
cartilaginous depositions already described there is an admixture
of bone. The quantity of bone generally bears a very small
proportion to the cartilage when they both occur together, as if
the bone proceeded from the cartilage, and not the cartilage from
the bone. It is sometimes seen growing from the surface of the
cartilage, and is sometimes deposited in its substance, and only
detected by the knife.
Simple ossification, as it occurs in the heart and arteries, has
been classed among the natural changes which the parts in question
are liable to undergo after a certain period of life. Of persons
above the age of sixty years the proportion is that of seven in ten
according to Bichât, in which ossification is discovered in some
part of the arterial system. It very rarely happens that simple
ossification is found before the period of old age: still it is
difficult not to regard it as a morbid process.
But ossification, when it is a mixed process, is unquestionably
the result of disease. It is met with at all periods of life; and
probably constitutes one of the terminations of inflammation. The
kind of morbid structures with which the bone is united leads to
this belief.
Fungous, and wart-like excrescences, are found in all those parts
of the internal lining of the heart, which have been already
mentioned as most subject to disease. They seem to be the result
of a new morbid action set up in parts already disorganized; for
I have not met with them where the membrane has been otherwise
healthy, but only where it has been thickened or cartilaginous, or
ossified, ruptured, or ulcerated. They grow either from the surface
of the membrane, or from its ruptured or ulcerated edges, and are
always in immediate contact with the circulating blood[6].
According to my observation, when a fungous or warty excrescence
has grown from the ruptured edges of the membrane, it has been from
them exclusively, and from no other part of the lining of the same
heart. And as rupture of the membrane seldom occurs in more than
one situation at a time, the heart of the same individual seldom
presents more than one excrescence of this kind: and as the aortic
valves are the parts most liable to rupture, it is there that this
single excrescence is most frequently found; not that rupture may
not take place elsewhere. I once saw a single _chorda tendinea_
ruptured; and a single fungous excrescence of considerable size
hanging from it into the cavity of the left ventricle.
Now, this morbid growth is evidently connected with the lacerated
state of the membrane in the conditions of its production, whereby
it is limited to a small space.
It is probable that the membrane is first ruptured; that its
lacerated edges inflame, and then throw out unhealthy lymph, or
unhealthy granulations, in the shape of these fungous or wart-like
excrescences. When they have sprung from a ruptured membrane, they
have, in the specimens which I have examined, been larger than when
they have arisen under other conditions.
But when such excrescences grow from the surface of the membrane
which is thickened and cartilaginous only, but not lacerated, they
are more apt to occur in many parts of it at the same time. I have
seen the valvular apparatus between the auricles and ventricles on
both sides, as well as the aortic valves of the same heart, studded
with them. They were all about the size of hemp seeds: they adhered
to the membrane with different degrees of tenacity, and wherever
they were capable of being detached, they left a rough surface.
The lining of the arteries has been known to give origin to morbid
growths of the same kind, which have obstructed the passage of
blood, and given occasion to the formation of a coagulum, which has
obliterated the pulse.
The internal lining of the heart is liable to ulceration, not as
a common consequence of simple inflammation, but as an occasional
consequence of some of those diseased conditions which have been
described.
It is most commonly found around scales and spiculæ of bone, and
under such circumstances as to leave no doubt that the bone itself
has furnished the source of irritation from which it springs. The
ulceration commences from the very border of the bony scale, as if
it was a process of nature for detaching it, and to a considerable
distance around the ulceration the membrane is reddened, and easily
detached from the subjacent structure. Where there are several
distinct scales of bone, it is not uncommon to find a circle of
ulceration around each of them.
Ulceration is also met with where there is a thickened and
cartilaginous state of the membrane without ossification. Under
these circumstances, as far as I know, it affects no definite form.
It is often a very destructive process of disease, obliterating
large portions of the valvular structure, and penetrating deep into
the muscular substance of the heart.
Rupture of the internal lining of the heart is not easily
distinguished from ulceration. In collections of morbid anatomy,
many unquestionable specimens of ulceration are described as
specimens of rupture. Rupture must always be looked for in the
valvular apparatus of the heart, _i. e._ in the valves themselves,
or in the chordæ tendineæ which are their appendages. It is
probably incapable of taking place elsewhere, except as a part of a
rupture, which involves the whole organ.
That solution of continuity which is evidently without loss of
substance; that of which the separated edges when they are brought
together are completely adapted to each other; also that which
is unaccompanied by any thickening or other morbid condition of
the valve; the solution of continuity which is found under these
circumstances, may safely be considered to proceed from rupture,
and not from ulceration[7].
But it is probable that these characteristic conditions do not long
remain after the occurrence of the rupture. Complete specimens of
them are very rare; but specimens are numerous where the solution
of continuity, by its form and direction, bespeaks rupture, while
its rounded edges and the general thickening of the valve denote
ulceration. These, it may be fairly conjectured, do in fact exhibit
a compound of both. The membrane was originally ruptured, but
disease has subsequently arisen and obscured the character of the
mechanical injury.
The greater number of those concretions, which were regarded by
the older anatomists as polypi of the heart, were unquestionably
portions of mere blood, which had undergone coagulation after
death. The blood remaining in the heart after death discharges
itself of its colouring matter as it coagulates, and, giving off
processes between the muscular fasciculi, assumes a shape which has
suggested the name of polypus[8].
I have often found (I presume, therefore, that it is not an
uncommon occurrence) coagula of an irregularly laminated texture
having their colouring matter not entirely discharged, but
unequally distributed through them, which have been most intimately
adherent to some part of the lining of the heart. Of these some
have admitted of separation, while the surface of the membrane and
the surface of the clot were left rough at the place of contact,
and others were incapable of being detached without the membrane
being detached along with them. The appendix of the left auricle is
a situation in which they are apt to occur, and they are generally
accompanied by an extensively diseased condition of the lining
membrane. These coagula, from their laminated texture, and from
the intimacy of their union with the internal lining, seem to be
essentially different from polypi of the heart. They appear to be
connected with a process of disease in the membrane, and to have
obtained their union with it long before the death of the patient.
I once saw two separate tumors, entirely resembling what are called
polypi, between the carneæ columnæ of the left ventricle, and
firmly adherent to the heart; and in the centre of each a distinct
formation of pus. The heart was otherwise healthy[9].
There are three preparations in the museum of the College of
Surgeons, put up by Mr. Hunter himself, and noted by him as
exhibiting "Tumors on the inner surface of the right ventricle,
seemingly composed of layers of coagulable lymph one upon another,
the central part having the appearance of glary mucus." This last
appearance (the mucus) no longer remains in any of the three, but
in its stead there is a cavity. The tumors which I have mentioned
as originally containing in their centre a distinct formation
of pus, also now present in its stead a cavity. The preparation
preserved at St. Bartholomew's, and those at the College of
Surgeons, are probably specimens of the same disease.
Here what in the recent parts seemed to be pus or glary mucus, and
the cavities still remaining in the preparations, must suggest the
suspicion, that these tumors, whether they grew from the surface or
were deposited from the blood, had become organized, and afterwards
inflamed; and that the inflammation had terminated in the formation
of an abscess.