Text book of veterinary medicine, Volume 1 (of 5)

by James Law

PALPITATION DEPENDENT ON ORGANIC DISEASE OF THE HEART.	PALPITATION INDEPENDENT OF ORGANIC DISEASE OF THE HEART.
1. Palpitation usually comes on slowly and gradually.	1. Palpitation usually sets in suddenly.
2. Palpitation constant, though more marked at one period than at another.	2. Palpitation not constant, having perfect intermissions.
3. Impulse of the heart usually stronger than natural, sometimes remarkably increased heaving and prolonged; at others irregular and unequal.	3. Impulse neither heaving nor prolonged; often abrupt knocking and circumscribed, and accompanied by a fluttering sensation (visible jerking or lifting) in the precordial region or epigastrium (flank and abdomen).
4. Palpitation often accompanied by the auscultatory signs of diseased valves.	4. Auscultatory signs of diseased valves absent; bellows sound often present in the large arteries and a continuous murmur in the veins.
5. Rythm of the heart regular, irregular, or intermittent; its action not necessarily quickened.	5. Rythm of heart usually regular, sometimes intermittent; its action generally more rapid than natural.
6. Mucous membranes often reddened and congested; dropsy of hind limbs common.	6. Mucous membranes generally pale; dropsy of hind limbs rare.
7. Palpitation increased by exercise, by stimulants and tonics, etc.; relieved by rest and frequently also by local and general bleeding and an antiphlogistic regimen.	7. Palpitation increased by close confinement; by local and general bleedings, etc.; relieved by moderate exercise and by stimulants and tonics, 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.