heart-muscle when a branch of the coronary artery is blocked either by
a thrombus or an embolus, or is obliterated by a progressive sclerosis.
The region supplied by the affected vessel is deprived of blood and
undergoes a process of infarction. In some instances the tissue is not
infiltrated with blood, as in an ordinary infarct, but has a pale
yellowish color and is very soft. When there is extravasation the color
is more reddish-brown. Histologically, the muscle-cells are found in a
state of granular degeneration, and on staining the nuclei do not take
the tint, and the whole tissue ultimately assumes the homogeneous
granular aspect of coagulation necrosis. There may be fatty
degeneration in the contiguous muscle-fibres, and finally, as with
infarcts in other organs, fibroid induration takes place. This process,
as before mentioned, plays an important part in the production of the
fibroid patches scattered through the myocardium. When fresh, the
softening of the affected region may be marked, and the name myomalacia
cordis which Ziegler[22] has suggested is so far suitable, but it seems
more appropriately applied to that condition of general softening of
the organ met with in severe fevers. This process most frequently
affects the left ventricle, and if extensive may lead to rupture.
[Footnote 22: _Loc. cit._]
The clinical aspects of this condition, as induced by sclerosis of the
coronary arteries, have been recently studied with great care by
Leyden.[23] In acute cases death occurs in a few hours with symptoms of
intense angina pectoris and heart failure. The subacute cases are
characterized by recurring anginoid attacks lasting from a few minutes
to half an hour. There may be attacks of asthma with heart weakness,
and signs of oedema of the lungs. The clinical picture is that of
angina pectoris, and the patient may have had similar attacks on
previous occasions.
[Footnote 23: _Zeitschrift f. klin. Med._, Bd. vii., 1884.]
2. Parenchymatous Degeneration.--The relation of inflammation of the
heart-substance to this degeneration is still somewhat indefinite. I
have under Myocarditis described an acute interstitial form
characterized by inter-fibrillar swelling with exudation and
proliferation of corpuscles, and often granular or fatty degeneration
of the muscle-cells. These changes may certainly be regarded as
inflammatory, and they are met with either in association with endo- or
pericarditis or in connection with specific fevers. Under the term
parenchymatous degeneration or cloudy swelling Virchow described[24] a
change of frequent occurrence in the heart-muscle and elsewhere, which
I think should be distinguished from myositis, although the two
processes may lead to alterations difficult to distinguish
macroscopically. It is characterized by a pale, turbid state of the
cardiac muscle, general, not limited, and a relaxed, soft, brittle
condition of the walls. The turbidity and softness are the special
features; there are no peri- or endocardial changes--simply the loss of
color and consistence. It is the softened heart of Laennec and of
Louis; and Stokes speaks of an instance in which "so great was the
softening of the organ that when the heart was grasped by the great
vessels and held with the apex pointing upward, it fell down over the
hand, covering it like the cap of a large mushroom."[25]
Microscopically, the fibres are indistinct, the protoplasm occupied by
fine granules which obscure the striæ, and sometimes the nuclei.
Proliferative changes rarely occur, although swelling and
multiplication of the nuclei and the interstitial cells have been
described. The granules may be extremely minute, or so large that they
are mistaken for fat. They are generally uniform in size, and are
scattered irregularly through the fibres. In extreme grades the entire
fibre may be occupied by them, and no trace of structure can be seen.
Dilute acids and alkalies dissolve the granules, but they resist the
action of ether, indicating their albuminous nature. This condition is
met with in the infectious diseases--typhoid, {611} typhus, small-pox,
pyæmia, remittent fever, etc.--particularly when the disease is
protracted and the temperature high. Apparently, we must regard it as
an expression of the effect of the poison upon the metabolism of the
fibres, inducing a separation of albuminous particles in a granular
form. That the high temperature alone does not produce it is
demonstrated by its absence in many other diseases in which this
condition prevails. The relation to fatty degeneration is not clear. It
would appear to precede the development of this change.
[Footnote 24: _Archiv_, vi.]
[Footnote 25: _Diseases of the Heart_, Am. ed., p. 373.]
The effect of this degeneration is virtually the same as that of
myocarditis, already described. It produces the weak heart of fever so
well described by Stokes,[26] with indistinct impulse, feeble or
imperceptible first sound, and progressive diminution of contractile
power. There is often a great reduction in the number of beats, which
may sink to 40 or 50 per minute. In severe cases of typhoid fever we
often have an opportunity of studying the progressive enfeeblement of
the heart with weakening or disappearance of the first sound.
[Footnote 26: _Loc. cit._, chap. vii.]
To Stokes we are indebted for the suggestion of the use of alcohol in
this condition, and the experience of the past forty years has fully
confirmed this practice of the Dublin school.
3. Fatty Heart.--Two conditions of the heart are recognized under this
heading--viz. fatty infiltration and fatty degeneration.
Fatty Infiltration.--Cor adiposum, Lipomatosis cordis, and Fatty
hypertrophy or overgrowth are synonyms found in the older and more
recent works.
A condition in which there is an excess of fat beneath the pericardium
and a growth of the same between the fibres of the myocardium. There is
normally a certain amount of fat in the cardiac groves, particularly
the auriculo-ventricular, and along the coronary arteries. An excess is
not infrequently met with in connection with general atrophy, whether
the result of disease or the natural decay of old age. Here it serves
as padding, and has no pathological significance. In very corpulent
persons there is always much subpericardial fat; it forms a part of the
general obesity, and in this state an excessive accumulation may lead
to a dangerous or even fatal impairment of the contractile power of the
heart. Obesity is the expression of a morbid tendency, generally
hereditary, to the deposition of fat in the connective tissues. A
sedentary life and the consumption of food rich in carbohydrates favor
this tendency, but we see it arise under conditions just the opposite
when the predisposition to polysarcia is marked. Males are more usually
affected than females, at least in Great Britain and Germany.
In the inspection of the bodies of very corpulent persons we find the
mediastinum occupied by masses of fat which may completely cover the
pericardium. The entire heart may be enveloped in a thick sheeting of
fat, through which not a trace of muscle-substance can be seen. Along
the groves, the regions of normal deposit, the layer may be an inch or
more in diameter. In some cases the muscle-substance beneath seems but
slightly involved; there may be superficial infiltration and
penetration of columns of fat between the bundles, but the thickness of
musculature is normal, and apart from the excessive deposition there is
not much amiss. In other instances the muscle-substance is seriously
affected; on section of the ventricular wall the fat is seen to
infiltrate the entire muscle, separating strands of fibres and reaching
almost to the endocardium. There may be places, indeed, in the thinner
parts of the ventricular walls in which there appears to be complete
substitution of the muscle by fat. Even the papillary bundles may
contain adipose tissue. The chambers are usually dilated and the entire
organ soft and relaxed. Microscopically, the fat-cells are everywhere
{612} seen infiltrating the muscle-tissue, separating the fibres and
inducing atrophy. In some cases, even when the condition is advanced,
the muscle-fibres appear normal, but in the majority fatty degeneration
is also present. Often in these cases the coronary vessels will be
found atheromatous.
The SYMPTOMS of fatty overgrowth will depend greatly on the degree of
infiltration, the state of the muscle-fibres--whether normal or
degenerated--and on the presence or absence of coronary atheroma. Many
very fat persons enjoy excellent health and have actively beating
hearts, which fail them only on severe exertion, when they get out of
wind and experience cardiac distress, perhaps palpitation. The pulse is
good and the heart sounds are clear. The signs of heart failure (which
may be due either to excessive infiltration or secondary degeneration
of the muscle, or both combined) in obese persons are generally very
marked--breathlessness on slight exertion, amounting oftentimes to
dyspnoea; attacks of asthma of a distressing nature coming on without
cause or after a full meal; cough, with or without bronchitis;
dizziness and pseudo-apoplectic attacks. Sudden death from syncope or
rupture of the heart is common. Dropsical symptoms and cyanosis may
supervene. The physical signs are those of heart weakness; impulse
imperceptible or very diffuse; area of dulness increased, but often
hard to delimit, with fat chest-walls and fatty mediastinum; sometimes
a soft systolic murmur at apex; radial pulse rapid, weak, and
irregular, in some instances very slow.
The DIAGNOSIS of the condition with such a series of symptoms in an
excessively stout person can offer but little difficulty.
The TREATMENT in the early stage should be directed to reducing the
general obesity, and such persons should be warned against taking too
violent exertion or subjecting the heart to unusual strain. Moderate
exercise, mental quietude, and careful dieting may do much toward
postponing heart failure, which, when established, calls for the
treatment which shall be described under Dilatation.
Fatty Degeneration.--An anomaly or disturbance of nutrition in which
minute particles of fat accumulate in the protoplasm of the
muscle-fibres, and impair the functional activity of the organ.
This is one of the most common of post-mortem conditions, and in mild
grades is met with in a great variety of diseases. The fat is a product
of the metabolism of the protoplasm of the muscle-fibres, and in a
normal state it (or its immediate antecedents) is oxidized; but when
either there is increased transformation or reduced oxidation the
products accumulate in the protoplasm, and are evident as minute
molecules or as distinct fine oil-droplets. The condition of cloudy
swelling or parenchymatous degeneration appears in many cases to
precede that of fatty degeneration, and sometimes the granules are of
such a size, so abundant, and resemble fat so closely that chemical
tests alone can distinguish between them.
A practical division of fatty degeneration is into--1, cases in which
the process has attacked a normal heart; and 2, cases in which we find
it associated with valvular disease and hypertrophic states of the
muscular walls.
In the first group we have _(a)_ The degeneration which accompanies the
failing nutrition of old age, of wasting diseases, and of cachectic
states. _(b)_ The fatty change in the heart-muscle so often a sequence
to, or coexisting with, the parenchymatous degeneration of fevers.
_(c)_ The extreme fatty degeneration so constantly associated with
profound anæmia. _(d)_ Certain poisons, particularly phosphorus;
arsenic, lead, and antimony also act in the same way. The slow
poisoning by alcohol is a very frequent cause of a gradually fatty
degeneration of the heart. And _(e)_ some local causes are important in
inducing this change in the previously normal organ. Pericarditis is
almost invariably associated with involvement of the superficial
myocardium, {613} either inflammatory or degenerative. Disease of the
coronary arteries is a frequent and important cause of fatty
metamorphosis. When due to the general conditions above mentioned, the
affection is widely distributed in the organ; when the result of
gradual narrowing of the vessels by atheroma, the distribution is in
the regions supplied by the affected vessels.
The second group comprises those cases in which the fatty degeneration
involves the muscle-substance in a condition of hypertrophy, and is an
important element in inducing the disturbance of compensation upon
which so many heart symptoms depend. Here the process may be more
local, affecting, for example, the left ventricle chiefly, as in the
hypertrophy from aortic valve disease or in association with contracted
kidneys, or the right ventricle in chronic lung affections and mitral
stenosis. More rarely we find the process confined chiefly to the
auricles, but there may be advanced changes of this nature in the
hypertrophied left auricle in mitral stenosis. The fatty degeneration
of an hypertrophied heart may be induced by any of the general causes
above referred to, but there are also special ones to which it is
liable. The chronic congestion which accompanies a dilated heart
affects the walls of the organ as well, and diminishes the vigor of the
coronary circulation. In emphysema and in mitral stenosis, and other
diseases which induce a dilated state of the right heart, fatty
degeneration, sometimes combined with fibroid change, is, as Jenner
pointed out,[27] very common. This state of the right chambers also
interferes with the proper oxygenation of the blood in the lungs, and
so acts in a double way. Degenerative changes in the coronary arteries
are specially prone to accompany valvular diseases, on which the
majority of cases of hypertrophy depend, and we have here one of the
most serious causes of fatty degeneration in this state. And, finally,
we see this change in some hypertrophied hearts without being able to
ascertain any exciting cause: a nutritive breakdown occurs, of which
the fatty degeneration is the expression. Possibly in such cases the
trophic nerve-influences may be at fault.
[Footnote 27: _Medico-Chirurgical Transactions_, xliii.]
Defective oxidation, in whatever way brought about, seems the common
factor in all forms of fatty degeneration. The process may be almost
confined to the heart or be more or less general in the solid viscera
and voluntary muscles. The diaphragm is sometimes much involved with
the heart, even when the other muscles show no signs of the change.
There certainly seems to be a special proneness to fatty degeneration
in the heart-muscle which may perhaps be associated with its incessant
activity. So great is the need of an abundant oxygen-supply that it
early feels any deficiency, and in consequence is the first muscle to
show nutritional changes.
Fatty degeneration is met with at all ages. I have seen it in the
hypertrophied right ventricle of a new-born infant, with stenosis of
the pulmonary artery. The cases dependent upon vascular changes are
most frequent after middle life. Males appear more frequently affected
than females. The form associated with anæmia is an exception to this
rule. Stout persons are not more liable to be affected than thin ones;
indeed, it is often, to use Paget's phrase, "a lean degeneration."
Sedentary habits, worry, grief, and other depressing emotions are
believed by some to have a predisposing influence. Persons with gouty
and arthritic tendencies are more prone to this change.
The anatomical condition is very characteristic even to the naked eye,
and the microscope may be required only in corroboration. It may be
local or general. In the former case the left ventricle is most
frequently affected, the right ventricle more rarely, and the auricles
very seldom. The amount of subpericardial fat may be slight. If the
process is advanced and in all the chambers, the heart looks large and
is flabby and relaxed. It is pale, of a light yellow-brown tint, buff
color, or, as it is sometimes expressed, a {614} faded-leaf color. The
consistence is greatly diminished, and the substance tears easily and
the finger can be readily thrust through the wall. Extreme grades are
met with in profound anæmia and in phosphorus-poisoning. The fatty
degeneration of coronary disease and of valvular affections is usually
more local, and the heart has often a brownish-yellow tint from the
coexistence of brown atrophy. In the left ventricle the papillary
columns and the layers of muscle just beneath the endocardium are most
affected, and in a curious streaked or patchy way--the tabby mottling
of some authors. A similar change may be seen in the right ventricle,
particularly in the hypertrophy from mitral disease. In the auricles
the right may show patches on the musculi pectinati, but on the left,
which is most often affected, the thick endocardium usually obscures
it. Chemically, it has been shown that in fatty degeneration the heart
may contain from 3 to 5 per cent. more fat than normal.
On microscopical examination of teased portions of the muscle the
fibres are broken and irregular, and there is much free fat, in form of
droplets, among them. The appearance of the fibres will vary with the
intensity of the process; in mild grades there are minute scattered
droplets in the protoplasm, not obscuring the nuclei or the striæ; but
in an advanced condition the fibres seem occupied completely with
minute globules, and no trace of structure can be seen. The patchy
distribution of the fatty degeneration in many cases, usually evident
to the naked eye, is corroborated by the microscope, and one may obtain
portions of the muscle with scarcely a normal fibre, while in a
contiguous bit the fibres are little if at all affected. In some
instances of general fatty degeneration in anæmia, and even in fevers,
as diphtheria, the process is so advanced that it is difficult to find
any normal-looking fibres. Brown atrophy is a frequent accompaniment of
fatty degeneration.
The effect of this change upon the heart is seen in a diminution of its
functional power; the contractile force is weakened and the organ
rendered incapable of doing its work efficiently. If the change occurs
in a previously normal heart, much will depend on the rapidity with
which it has supervened. Repeated hemorrhages or poisoning by
phosphorus will induce in a few days an extreme degree of weakness
rarely seen in the fatty degeneration of chronic anæmia--perhaps
equally extensive. 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.
The SYMPTOMS of fatty degeneration of the heart are by no means
definite, being those of defective cardiac power. It is often met with
post-mortem when not expected, and on the other hand we may fail to
find it even when the symptoms seem to point very clearly to its
existence. In chronic anæmia, in chlorosis, in fevers and wasting
diseases the process may be extreme, without leading to any more marked
symptoms than feeble action of the heart, palpitation on exertion or
excitement, with signs of slight dilatation, and a soft mitral systolic
murmur from incompetency of the valves. In cases of idiopathic anæmia,
in which the fatty degeneration is perhaps more marked than in any
other condition except phosphorus-poisoning, the pulse is frequently
full, though soft, and regular so long as the patient is quiet. The
symptoms of fatty degeneration in cases of valvular disease with
hypertrophy are simply those of failing compensation, and we see the
same process in the non-valvular hypertrophy of chronic Bright's
disease. But, apart from these conditions, fatty degeneration occurs as
part of a process of general failure {615} of nutrition, premature or
senile. These form the cases of idiopathic fatty heart which seem so
constantly to be associated with atheromatous changes in the coronary
vessels. English writers have dealt specially with this form, which
certainly appears to be more prevalent in Great Britain than on this
continent or in Europe. In these cases there may be general obesity,
but as often the subjects are of spare habit, with full atheromatous
arteries, and other indications, perhaps, of early senility. They are
usually persons who have lived freely and taken stimulants in excess.
Among the symptoms believed to indicate fatty degeneration in these
cases are--weak, irregular action of the heart, with a small
intermittent pulse; cardiac pain, sometimes anginoid in character;
dyspnoea, particularly on exertion, as in ascending an incline; signs
of cerebral anæmia, indicated by vertigo or pseudo-apoplectic attacks
and loss of mental power; the presence of an arcus senilis; and, as a
final symptom, Cheyne-Stokes respiration.
Persistent irregularity in the action of the heart in a person with
atheromatous arteries, and dyspnoea on exertion, without signs of
valvular affection, are certainly suggestive of degeneration of the
muscle-fibres of the heart. In some instances there has been noted a
greatly diminished number of beats, 40 or 50 per minute, or even
slower. Irregular action of the heart may, however, persist for years
without indicating any serious mischief.[28] The yellow fatty arcus
senilis is believed by many physicians to indicate a weak fatty heart,
and it does occur in many persons of soft flabby habit of body with
degenerated arteries and evidences of premature decay; but by itself it
is of no value as a sign of vascular degeneration. It must not be
confounded with the opaque white calcareous arcus not uncommon in
elderly people, and met with occasionally in middle-aged persons. The
Cheyne-Stokes breathing so often referred to as specially associated
with fatty heart is, in my experience, a much more frequent concomitant
of uræmic states.
[Footnote 28: In the spring of 1882, I saw, for Geo. W. Campbell, a
gentleman aged eighty-two, a man of remarkable vigor, mental and
bodily. He had an extraordinarily irregular yet full pulse, with
atheromatous arteries--a condition which he assured me had been
constantly present for close upon forty years, and had been a source of
needless anxiety to many physicians, and for some years to himself.]
The physical signs of fatty degeneration of the heart are a weak
impulse, often diffuse, and if the patient is thin the area of dulness
may be found increased. In stout persons it is difficult to determine
dilatation on account of the fat inside and out. The sounds on
auscultation are generally weak, distant, and muffled, but in the fatty
degeneration of anæmia the first will often be found sharp and
distinct, though short and more like the second sound. A soft murmur,
systolic in character, is not infrequently heard at the apex, and
believed to be due to muscular incompetency.
The DIAGNOSIS is beset with difficulties, and in most cases we have to
be content with probabilities, except in the instances due to anæmia,
etc. Permanent weakness of impulse and the symptoms it entails, with
signs of degeneration of tissue as shown by atheromatous arteries, are
the most suggestive features, but even about them there are
uncertainties. My own errors and a contemplation of those of several
very eminent clinicians, taken in connection with the fact that some of
the most typical cases of fatty heart which come under my observation
have been instances of sudden death in persons pursuing their
avocations, have made me very cautious in the diagnosis of this
condition.