contract forcibly. This results in a rapid but weak, soft pulse and
irregular heart sounds. The pulse may be quite irregular as a result of
the irregular, tumultuous action of the heart. There is great general
weakness, shortness of breath, and rapid respiratory movements. In some
cases, where the muscle is very much softened and weakened, or, perhaps
when an abscess forms in the wall of the heart, the course of the
disease is very rapid and terminates suddenly from paralysis or rupture
of the heart.
_Alterations._--The heart muscle has a brownish or yellowish, boiled
appearance, and is so brittle that it tears easily. There may be a
spotted appearance of the muscle from the intense changes in structure
in small areas. These small areas may be due to suppuration, in which
case they have the characteristics of small abscesses. This last
condition is seen in pyemia (blood poisoning). If the disease is of long
duration, the fibrous tissue in the wall of the heart may increase to
such an extent as to produce an unnatural hardness of the wall.
_Treatment._--In this disease the nutrition and strength of the heart
should be kept up as much as possible with good food, good care, and
heart tonics and stimulants. The horse should be tempted to eat such
foods as he will take; he should be kept in an airy box stall; his legs
should be well rubbed as often as necessary to keep them warm and
bandaged loosely with flannel bandages. Internally the horse may have
strychnia, in 2-grain doses twice daily, whisky in 4-ounce doses every
two to four hours, digitalis in the form of the tincture in doses of 1
dram every three to six hours. Artificial Carlsbad salts in heaping
tablespoonful doses in the feed may be given three times daily for a
couple of weeks. Rest is of the greatest importance and should be
allowed for a few weeks after recovery seems to be complete.
ENDOCARDITIS, OR INFLAMMATION OF THE LINING MEMBRANE OF THE HEART.
Endocarditis frequently occurs as a complication of rheumatism, some of
the specific or zymotic fevers, specific poisoning, etc. This is a more
frequent disease among horses than is generally known, and often gives
rise to symptoms which at first are obscure and unnoticed.
In influenza we may find the heart becoming involved in the disease, in
consequence of the morbid material conveyed through the heart in the
blood stream. In view of the fact that many affections in even remote
portions of the body may be traced directly to a primary endocardial
disease, we shall feel justified in inviting special attention to this
disease.
Endocarditis may be acute, subacute, or chronic. In acute inflammation
we find a thickening and a roughened appearance of the endocardium
throughout the cavities of the heart. This condition may be followed by
a coagulation of fibrin upon the inflamed surface, which adheres to it,
and by attrition soon becomes worked up into shreddy-like granular
elevations. This may lead to a formation of fibrinous clots in the heart
and sudden death early in the disease the second or third day.
Subacute endocarditis, which is the most common form, may not become
appreciable for several days after its commencement. It is characterized
by being confined to one or more anatomical divisions of the heart, and
all the successive morbid changes follow each other in a comparatively
slow process. Often we would not be led to suspect heart affection were
it not for the distress in breathing, which it generally occasions when
the animal is exercised, especially if the valves are much involved.
When coagula or vegetations form upon the inflamed membrane, either in
minute shreds or patches, or when formation of fibrinous clots occurs in
the cavity affected, some of these materials may be carried from the
cavity of the heart by the blood current into remote organs,
constituting emboli that are liable to suddenly plug vessels and thereby
interrupt important functions. In the great majority of either acute or
subacute grades of endocarditis, whatever the exciting cause, the most
alarming symptoms disappear in a week or 10 days, often leaving,
however, such changes in the interior lining or valvular structures as
to cause impairment in the circulation for a much longer period of time.
These changes usually consist of thickening or induration of the
inflamed structures. But while the effects of the inflammation in the
membrane lining the walls of the ventricles may subside to such a degree
as to cause little or no inconvenience, or even wholly disappear, yet
after the valvular structures have been involved, causing them to be
thicker, less flexible than normal, they usually remain, obstructing the
free passage of the blood through the openings of the heart, thereby
inducing secondary changes, which take place slowly at first, but
ultimately seriously impair the animal's usefulness. What was but a
slight obstruction to the circulation during the first few weeks after
the subsidence of the cardiac inflammatory attack becomes in process of
time so much increased as to induce increased growth in the muscular
structure of the heart, constituting hypertrophy of the walls of the
ventricles, more particularly of the left, with corresponding fullness
of the left auricle and pulmonary veins, thereby producing fullness of
the capillaries in the lungs, pressure upon the air cells, difficult or
asthmatic breathing--greatly increased in attempts to work--until in a
few months many of these cases become entirely disabled for work.
Sometimes, too, dropsical effusions in the limbs or into the cavities of
the body result from the irregular and deficient circulation.
Derangement of the urinary secretion, with passive congestion of the
kidneys, may also appear.
Endocardial inflammation is seldom fatal in its early stages, but in
many cases the recovery is incomplete, for a large proportion is left
with some permanent thickening of the valves, which constitutes the
beginning of valvular disease.
_Symptoms._--Endocarditis may be ushered in by a chill, with sudden and
marked rise in temperature. The pulse rapidly decreases in strength or
may become irregular, while the heart beats more or less tumultuously.
In the early stages soft-blowing sounds may be heard by placing the ear
over the heart on the left side, which correspond in number and rhythm
to the heart's action. Excessive pain, though not so great as in acute
pleuritis, is manifested when the animal is compelled to trot; very
often difficulty in breathing, or shortness of breath, on the slightest
exertion develops early in the attack. When the valves are involved in
the inflammatory process the visible mucous membranes become either very
pale or very dark colored, and fainting may occur when the head is
suddenly elevated. When the valves of the right side are affected we may
find a regurgitant pulsation in the jugular vein. Occasionally it
happens that the heart contracts more frequently than the pulse
beats--that is, there may be twice as many contractions of the heart in
a minute as there are pulse waves in the arteries. The pulse is always
very fast. In some cases we find marked lameness of the left shoulder,
and when the animal is turned short to the left side he may groan with
pain, and the heart's action become violently excited, although
pressure against the chest wall will not produce pain unless roughly
applied. The animal is not disposed to eat or drink much; the surface of
the body and legs are cold--rarely excessively hot--and frequently the
body of the animal is in a subdued tremor. In nearly all cases there is
partial suppression of the urinary secretion. The symptoms may continue
with very little modification for three or four days, sometimes seven
days, without any marked changes. If large fibrinous clots form in the
heart the change will be sudden and quickly prove fatal unless they
become loosened and are carried away in the circulation; then apoplexy
may result from the plugging of arteries too small to give further
transmission. If the animal manifests symptoms of improvement, the
changes usually are slow and steady until he feels apparently as well as
ever, eats well, and moves freely in his stall or yard. When he is taken
out, however, the seeming strength often proves deceptive, as he may
quickly weaken if urged into a fast gait, the breathing becomes
quickened with a double flank movement as in heaves, and all the former
symptoms reappear in a modified degree. An examination at this stage may
reveal valvular insufficiency, cardiac hypertrophy, or pulmonary
engorgement.
In fatal cases of endocarditis death often occurs about the fourth day,
from the formation of heart clot or too great embarrassment of the
circulation. Endocarditis may be suspected in all cases where plain
symptoms of cardiac affection are manifested in animals affected with
influenza, rheumatism, or any disease in which the blood may convey
septic matter.
Acute endocardial inflammation may be distinguished from pleuritis by
the absence of any friction murmur, absence of pain when the chest wall
is percussed, and the absence of effusion in the cavity of the chest. It
may be distinguished from pericarditis by the absence of the friction
sounds and want of an enlarged area of dullness on percussion.
_Treatment._--The objects to be attained by treatment will be to remove
or mitigate as much as possible the cause inducing the disease; to find
a medicine which will lessen the irritability of the heart without
weakening it; and, last, to maintain a free urinary secretion and
prevent exudation and hypertrophy. So long as there is an increase of
temperature, with some degree of scantiness of the urine, it may be safe
to believe that there is some degree of inflammatory action existing in
the cardiac structures, and as long as any evidence of inflammatory
action remains, however moderate in degree, there is a tendency to
increase or hypertrophy of the connective tissue of the heart or valves,
thereby rendering it almost certain that the structural changes will
become permanent unless counteracted by persistent treatment and
complete rest.
The tincture of digitalis, in 20-drop doses, repeated every hour, is
perhaps the most reliable agent we know to control the irritability of
the heart, and this also has a decided influence upon the urinary
secretion. After the desired impression upon the heart is obtained the
dose may be repeated every two or three hours, or as the case may
demand. Tincture of strophanthus, in 2-dram doses, will quiet the
tumultuous action of the heart in some cases where the digitalis fails.
Bleeding, blistering, and stimulating applications to the chest should
be avoided. They serve to irritate the animal and can do no possible
good. Chlorate of potassium in 2-dram doses may be given in the drinking
water every four hours for the first five or six days, and then be
superseded by the nitrate of potassium in half-ounce doses for the
following week or until the urinary secretion becomes abnormally
profuse. Where the disease is associated with rheumatism, 2-dram doses
of salicylate of soda may be substituted for the chlorate of potassium.
To guard against chronic induration of the valves, the iodid of
potassium, in 1 to 2 dram doses, should be given early in the disease
and may be repeated two or three times a day for several weeks. When
chronic effects remain after the acute stage has passed this drug
becomes indispensable.
When dropsy of the limbs develops, it is due to weakened circulation or
functional impairment of the kidneys. When there is much weakness in the
action of the heart, or general debility is marked, the iodid of iron,
in 1-dram doses, combined with hydrastis, 3 drams, may be given three
times a day. Arsenic, in 5-grain doses twice a day, will give excellent
results in some cases of weak heart associated with difficult breathing.
In all cases absolute rest and warm stabling, with comfortable clothing,
become necessary, and freedom from work should be allowed for a long
time after all symptoms have disappeared.
PERICARDITIS, OR INFLAMMATION OF THE SAC INCLOSING THE HEART.
_Causes._--Pericarditis may be induced by cold and damp stabling,
exposure and fatigue, from wounds caused by broken ribs, etc. Generally,
however, it is associated with an attack of influenza, rheumatism,
pleuritis, etc.
_Symptoms._--Usually the disease manifests itself abruptly by a brief
stage of chills coincident with pain in moving, a short painful cough,
rapid and short breathing, and high temperature, with a rapid and hard
pulse. In the early stages of the disease the pulse is regular in beat;
later, when there is much exudation present in the pericardial sac, the
heartbeat becomes muffled, and may be of a double or rebounding
character. By placing the ear against the left side of the chest behind
the elbow a rasping sound may be heard, corresponding to the frequency
of the heartbeat. This is known as a friction sound. Between the second
and fourth days this sound may disappear, due to a distension of the
pericardium by an exudate or serous effusion. As soon as this effusion
partly fills the pericardium, percussion will reveal an abnormally
increased area of dullness over the region of the heart, the heartbeats
become less perceptible than in health, and in some cases a splashing or
flapping sound may become audible.
If the effusion becomes absorbed, the friction sound usually recurs for
a short time; this friction may often be felt by applying the hand to
the side of the chest. In a few cases clonic spasms of the muscles of
the neck may be present. In acute pericarditis, when the effusion is
rapid and excessive, the animal may die in a few days or recovery may
begin equally as early. In subacute or in chronic cases the effusion may
slowly become augmented until the pressure upon the lungs and
interference with the circulation become so great that death will
result. Whether the attack is acute, subacute, or chronic, the
characteristic symptoms which will guide us to a correct diagnosis are
the friction sound, which is always synchronous with the heart's action,
the high temperature with hard, irritable pulse, and, in cases of
pericardial effusion, the increased area of dullness over the cardiac
region. When the disease is associated with influenza or rheumatism,
some of the symptoms may be obscure, but a careful examination will
reveal sufficient evidence upon which to base a diagnosis. When
pericarditis develops as a result of or in connection with pleuritis,
the distinction may not be very clearly definable, neither will many
recover. When it results from a wound or broken rib, it almost
invariably proves fatal.
_Pathology._--Pericarditis may at all times be regarded as a very
serious affection. At first we will find an intense injection or
accumulation of blood in the vessels of the pericardium, giving it a red
and swollen appearance, during which we have the friction sound. In 24
to 48 hours this engorgement is followed by an exudation of
sero-fibrinous fluid, the fibrinous portion of which may soon form a
coating over the internal surface of the pericardial sac, and may
ultimately form a union of the opposing surfaces. Generally this
adhesion will only be found to occupy a portion of the surfaces. As the
serous or watery portion of this effusion is absorbed, the distinctness
of the friction sound recurs, and may remain perceptible in a varied
degree for a long time. When the serous effusion is very great, the
pressure exerted upon the heart weakens its action, and may produce
death soon; when it is not so great, it may cause dropsies of other
portions of the body. When the adhesions of the pericardial sac to the
body of the heart are extensive, they generally lead to increased
growth, or hypertrophy, of the heart, with or without dilatation of its
cavities; when they are but slight, they may not cause any
inconvenience.
_Treatment._--In acute or subacute pericarditis the tincture of
digitalis may be given in 20 to 30 drop doses every hour until the pulse
and temperature become reduced. Whisky or carbonate of ammonia may be
given regularly as stimulants. Bandages should be applied to the legs;
if the legs are very cold, tincture of capsicum should be first applied;
the body should be warmly clothed in blankets, to promote perspiration.
When the suffering from pain is very severe, 10 grains of morphin may be
given by the mouth once or twice a day; nitrate of potassium, half an
ounce, in drinking water, every six hours; after the third day, iodid of
potassium, in 2-dram doses, may be substituted. Cold packs to the chest
in the early stages of the disease may give marked relief, or, late in
the disease, smart blisters may be applied to the sides of the chest
with benefit. If the disease becomes chronic, iodid of iron and gentian
to support the strength will be indicated, but the iodid of potassium,
in 1 or 2 dram doses, two or three times a day, must not be abandoned so
long as there is an evidence of effusion or plastic exudate accumulating
in the pericardial sac. Where the effusion is great and threatens the
life of the patient, tapping by an expert veterinarian may save the
animal.
VALVULAR DISEASE OF THE HEART.
Acute valvular disease can not be distinguished from endocarditis, and
chronic valvular affections are generally the result of endocardial
inflammation. The valves of the left side are the most subject--the
bicuspid or mitral and the aortic or semilunar. The derangement may
consist of mere inflammation and swelling, or the edges of the valves
may become covered by the organization of the exudation, thus narrowing
the passage. Valvular obstruction and adhesions may occur or the
tendinous cords may be lengthened or shortened, thus obstructing the
orifices and permitting the regurgitation of blood. In protected cases
the fibrous tissue of the valves may be transformed into fibro-cartilage
or bone, or there may be deposits of salts of lime beneath the serous
membrance, which may terminate in ulceration, rupture, or fissures.
Sometimes the valves become covered by fibrinous, fleshy, or hard
vegetations, or excrescences. In cases of considerable dilatation of the
heart there may be atrophy and shrinking of the valves.
_Symptoms._--Valvular disease may be indicated by a venous pulse,
jerking pulse, intermittent pulse, irregular pulse; palpitation;
constant abnormal fullness of the jugular veins; difficulty of breathing
when the animal becomes excited or is urged out of a walk or into a
fast trot; attacks of vertigo; congestion of the brain; dropsical
swelling of the limbs. A blowing, cooing, or bubbling murmur may
sometimes be heard by placing the ear over the heart on the left side of
the chest.
Hypertrophy, or dilatation, or both, usually follow valvular disease.
_Treatment._--When the pulse is irregular or irritable, tonics, such as
preparations of iron, gentian, and ginger, may be given. When the action
of the heart is jerking or violent, 20 to 30 drop doses of tincture of
digitalis or of veratrum viride may be given until these symptoms abate.
As the disease nearly always is the result of endocarditis, the iodid of
potassium and general tonics, sometimes stimulants, when general
debility supervenes, may be of temporary benefit. Very few animals
recover or remain useful for any length of time after once marked
organic changes have taken place in the valvular structure of the heart.
ADVENTITIOUS GROWTHS IN THE HEART.
Fibrous, cartilaginous, and bony formations have been observed in some
rare instances in the muscular tissue. Isolated calcareous masses have
sometimes been embedded in the cardiac walls. Fibrinous coagula and
polypous concretions may be found in the cavities of the heart. The
former consist of coagulated fibrin, separated from the mass of blood,
of a whitish or yellowish white color, translucent, of a jellylike
consistence, and having a nucleus in the center. They may slightly
adhere to the surface of the cavity, from which they can easily be
separated without altering the structure of the endocardium. They
probably result from an excess of coagulability of fibrin, which is
produced by an organization of the lymph during exudation. They are
usually found in the right auricle and ventricle.
Polypous concretions are firmer than in the preceding, more opaque, of a
fibrous texture, and may be composed of successive layers. In some
instances they are exceedingly minute, while in others they almost fill
one or more of the cavities. Their color is usually white, but
occasionally red from the presence of blood. They firmly adhere to the
endocardium, and when detached from it give it a torn appearance.
Occasionally, a vascular communication seems to exist between them and
the substance of the heart. They may be the result of fibrinous
exudation from inflammation of the inner surface of the heart or the
coagulation of a portion of the blood which afterwards contracts
adhesion with the heart. These concretions prove a source of great
inconvenience and often danger, no matter how formed. They cause a
diminution in the cavity in which they are found, thus narrowing the
orifice through which the blood passes, or preventing a proper
coaptation of the valves, which may produce most serious valvular
disease.
_Symptoms._--These are frequently uncertain; they may, however, be
suspected when the action of the heart suddenly becomes embarrassed with
irregular and confused pulsations, great difficulty of breathing, and
the usual signs dependent upon the imperfect arterialization of the
blood.
_Treatment._--Stimulants, whisky, or carbonate of ammonia may be of
service.
PALPITATION OF THE HEART.
This is a tumultuous and usually irregular beating of the heart. It may
be due to a variety of causes, both functional and organic. It may occur
as a result of indigestion, fright, increased nervousness, sudden
excitement, excessive speeding, etc. (See "Thumps," p. 225.)
_Symptoms._--The heart may act with such violence that each beat may jar
the whole body of the animal; very commonly it may be heard at a short
distance away from the animal. It can usually be traced very readily to
the exciting cause, which we may be able to avoid or overcome in the
future and thereby obviate subsequent attacks. Rest, a mild stimulant,
or a dose or two of tincture of digitalis or opium will generally give
prompt relief. When it is due to organic impairment of the heart it must
be regarded as a symptom, not as a matter of primary specific treatment.
SYNCOPE, OR FAINTING.
Actual fainting rarely occurs among horses. It may, however, be induced
by a rapid and great loss of blood, pain of great intensity, a
mechanical interference with the circulation of the brain, etc.
_Symptoms._--Syncope is characterized by a decrease or temporary
suspension of the action of the heart and respiration, with partial or
total loss of consciousness. It generally occurs suddenly, though there
may be premonitory symptoms, as giddiness, or vertigo, dilated pupil,
staggering, blanching of the visible mucous membranes, a rapidly sinking
pulse, and dropping to the ground. The pulse is feeble or ceases to
beat; the surface of the body turns cold; breathing is scarcely to be
perceived, and the animal may be entirely unconscious. This state is
uncertain in duration--generally it lasts only a few minutes; the
circulation becomes restored, breathing becomes more distinct, and
consciousness and muscular strength return. In cases attended with much
hemorrhage or organic disease of the heart, the fainting fit may be
fatal; otherwise it will prove but a transient occurrence. In paralysis
of the heart the symptoms may be exactly similar to syncope. Syncope may
be distinguished from apoplexy by the absence of stertorous breathing
and lividity of the visible mucous membranes.