Convulsive contraction of the heart, functional or structural
diagnostic features of these. Significance of the functional disorder,
genera most liable. Treatment, quiet, heart tonic, digitalis, correct
other disorders.
These consist in a sudden violent and convulsive beating of the heart,
not connected with any appreciable structural disease. They differ
chiefly from the palpitations of organic disease of the heart in the
absence of any apparent local change to account for their occurrence.
The following table from Bellingham furnishes a number of criteria
equally valuable in the lower animals as in man.
PALPITATION DEPENDENT ON ORGANIC │PALPITATION INDEPENDENT OF ORGANIC
DISEASE OF THE HEART. │ DISEASE OF THE HEART.
│
1. Palpitation usually comes on │1. Palpitation usually sets in
slowly and gradually. │ suddenly.
2. Palpitation constant, though │2. Palpitation not constant, having
more marked at one period than at│ perfect intermissions.
another. │
3. Impulse of the heart usually │3. Impulse neither heaving nor
stronger than natural, sometimes │ prolonged; often abrupt knocking
remarkably increased heaving and │ and circumscribed, and
prolonged; at others irregular │ accompanied by a fluttering
and unequal. │ sensation (visible jerking or
│ lifting) in the precordial region
│ or epigastrium (flank and
│ abdomen).
4. Palpitation often accompanied by│4. Auscultatory signs of diseased
the auscultatory signs of │ valves absent; bellows sound
diseased valves. │ often present in the large
│ arteries and a continuous murmur
│ in the veins.
5. Rythm of the heart regular, │5. Rythm of heart usually regular,
irregular, or intermittent; its │ sometimes intermittent; its
action not necessarily quickened.│ action generally more rapid than
│ natural.
6. Mucous membranes often reddened │6. Mucous membranes generally pale;
and congested; dropsy of hind │ dropsy of hind limbs rare.
limbs common. │
7. Palpitation increased by │7. Palpitation increased by close
exercise, by stimulants and │ confinement; by local and general
tonics, etc.; relieved by rest │ bleedings, etc.; relieved by
and frequently also by local and │ moderate exercise and by
general bleeding and an │ stimulants and tonics,
antiphlogistic regimen. │ particularly the preparations of
│ iron.
Palpitations in the lower animals not dependent on any structural
disease of the heart are usually due to some violent mental emotion,
such as fear or joy. The author once possessed a fast and clever cob,
having no sign of organic disease, and equal to the severest work on the
road without showing signs of exhaustion, but which nevertheless was
affected by palpitation when threatened with a cane in his stall, or if
he had been guilty of some wilful misdemeanor for which he dreaded
punishment. In such cases the heart’s action was accelerated and the
beating could be heard loudly for a distance of several yards. They are
especially common in dogs under strong mental emotion (joy, fear), and
in dogs and pigs suffering from digestive disorder (worms) or chest
diseases.
Percivall collects a series of cases from the _Veterinarian_ under the
head of _Spasm of the Diaphragm_, a diagnosis originating in the jerking
movement of the flank, a symptom which, as is shown in the above table,
is common to man as well. Leblanc equally collects cases from the French
veterinary journals and acknowledges their true character. One of these
observed by Coulbeaux is thus described: “The respiratory movements are
interrupted by a violent lifting of the flanks, confined to the upper
part, and so intense as to be appreciated by the hand as well as the
eye. The lifting of the flank which is limited to a few square inches of
surface precisely in the hollow of this region, is perfectly isochronous
with the beats of the heart, which cannot be appreciated but by the
ear.”
A case reported by Levrat at greater length may also be given. The
subject a mare, fifteen years old, and kept for hire, was attacked
without any known cause. “There was a jerking of the whole body produced
by the extraordinary force of the beats of the heart which struck
violently against the back towards the upper ends of the first asternal
ribs on the left side. The shock is very distinct and does not appear to
be due to any tumor interposed between the heart and the ribs; its force
is such that it causes a movement of the whole body, which can be seen
at a great distance. The beats of the heart very regular, numbering
fifty per minute, were heterochronous with the pulsations of the
submaxillary artery, which are of the same number.” (The pulsation was
evidently retarded). “The pulse was soft and regular. The breathing was
peculiar. On approaching the ear to the nostrils the animal is heard to
make three successive inspirations which coincide with the beats of the
heart; each of these inspirations is followed by an expiration so short
and feeble that the expired air can not be felt; the fourth is followed
by full expiration sustained during three beats of the heart.” This form
of respiration was continued without intermission for an entire day.
In three cases observed at the Lyons Veterinary School the disease
continued for eight days. In all these and twenty more observed by
Leblanc, the patients invariably recovered. The steady persistence of
the disease for several days and the subsequent complete recovery under
the unaided action of digitalis would seem to warrant the conclusion
that such cases were really accompaniments of structural diseases of the
heart and not mere functional disorders. Even inflammation of the lining
membrane of the heart often exists without any obvious fever or other
manifest symptom of illness, and in the dissecting rooms of medical
schools nothing is more common than to find traces of pre-existing heart
disease in patients whose whole life had been passed without the
suspicion of such a malady.
A number of such cases observed in England and on the European Continent
are adduced to prove spasm of the diaphragm or of the abdominal muscles,
(Delafond), and great importance is attached to the fact that the
convulsive movements of the abdomen and loins are heterochronous with
the beats of the heart. This lack of exact coincidence however does not
seem to amount to more than a perceptible delay after the heart beat,
just as the maxillary pulsation is delayed in case of aneurism of the
aorta. This has been my own experience with such cases. The flank
movements have been equal in number to the heart beats or have
corresponded to certain beats in the heart cycle, and have been
perceptibly retarded in accordance with the necessity for time for the
transmission of the blood wave along the posterior aorta and the
development of the reflex action which set the phrenic and abdominal
muscles in motion. We must of course accept the convulsive action of the
phrenic and abdominal muscles, only it would seem that each such
movement has its starting point in the contraction of the heart. In
cases that show no relation in number nor succession with the heart
beats, we can freely acknowledge a neurosis starting at a point
different from the heart, but in all examples which are manifestly
connected with heart movements, and readily curable by the heart-tonic
digitalis, the recognition of the cardiac derangement as an initial
factor is sound alike in pathology and practice.
Nervous and purely functional palpitations are probably confined to
cases in which they are manifested at intervals appearing under the
influence of some transient excitement, and continuing only for a few
minutes at a time.
In the anæmic or bloodless condition the palpitation of weakness is
often observed under the slightest exciting cause. It is then associated
with a pallid state of the visible mucous membranes, a weak, trickling
pulse and a blowing murmur in the larger veins.
Palpitations are much more frequent in pigs and dogs than in horses.
_Treatment._ Quietness and avoidance of all excitement are first to be
secured, then the action of the heart is to be calmed and regulated by
the use of digitalis. To the horse 15 to 30 grains of the powered leaves
may be given thrice daily, and to the dog from two to four grains at
equal intervals. When the disease is associated with anæmia this agent
may still be used in combination with the various tonic remedies
recommended, but in the smallest doses only as the heart is usually
morbidly sensitive to external influences. Chloral hydrate has been used
with success. Bromides, valerian, and belladonna may be tried in
obstinate cases. Any other deviation from a healthy condition must be
noted and corrected, especially any disordered condition of the stomach
or bowels.