THE TWO KINDS OF SYNCOPE.
Dr. Patrick Black has made an objection to the fact of the patients having died of paralysis, or over-narcotism of the heart, in the accidents from chloroform.[[132]] He says that paralysis of the heart would be death by syncope, but that the symptoms before death, and the conditions of the organs met with afterwards, are not in accordance with such a view of the case. In order to show that both the symptoms and the after death appearances, in the fatal cases of inhalation of chloroform, are consistent with paralysis of the heart, it is necessary to point out the difference between ordinary syncope and cardiac syncope. One of the best examples of ordinary, or what may be called anæmic syncope, is that which occurs in a common blood-letting, whilst the patient is in the sitting posture. When the bloodvessels, especially the veins, which at all times contain the greater part of the blood in the body, do not accommodate themselves fast enough to the diminished quantity of blood, the right cavities of the heart are supplied with less and less of the circulating fluid; and in a little time are not supplied at all, when the heart ceases to beat, in accordance with the observation of Haller, that it does not pulsate when it is not supplied with blood. The moment the heart ceases to supply blood to the brain there are loss of consciousness and stoppage of respiration; but on the patient being placed in the horizontal position the blood flows readily into the right cavities of the heart from the great veins of the abdomen and lower extremities; the heart immediately recommences its contractions; the brain is again supplied with blood, and respiration and consciousness return.[[133]]
The blood may remain in the ordinary quantity; but if the bloodvessels do not keep up their usual support, and exert a sufficient pressure on their contents, the same kind of syncope will occur as that from blood-letting. The late Sir George Lefevre related the case of a lady who fainted whenever she left her bed, and assumed the upright posture; no cause could be found for this until it was ascertained that she suffered from varicose veins of the legs: bandages to these extremities prevented the fainting. It is obvious that in this case the mechanism of the syncope was the same as that in blood-letting; the distension of the varicose veins under the weight of the superincumbent blood had the same effect in preventing the supply to the right cavities of the heart, as if the blood had been entirely removed. The faintness which often occurs on first rising, when a person has long kept the recumbent posture from any local cause, is probably of the same kind; the veins not having had to support the weight of the usual column of blood for some days or weeks, lose their tone we may presume, and yield when they are all at once subjected to the weight of a column of blood extending from the lower extremities to the heart, so that this organ ceases to be properly supplied with the circulating fluid.
In cardiac syncope, on the other hand, the cavities of the heart, or at all events the right cavities of this organ, are always full, whether the syncope depend on paralysis of the heart by a narcotic, or inherent weakness of its structure, or on its being overpowered by the quantity of blood with which it is distended. After death from this kind of syncope, if the blood have not been displaced by artificial respiration or other causes, the right cavities of the heart and the adjoining great veins will be found filled with blood, and the lungs will in many cases be more or less congested. The appearances in short will be very much the same as in asphyxia by privation of air, which ends in a kind of cardiac syncope, the stoppage of the heart being partly due to over-distension of its right cavities, and partly to loss of power in its structure, from the want of a supply of oxygenated blood through the coronary arteries. In death by anæmic syncope, on the contrary, all the cavities of the heart are found empty, or nearly so, and the same is frequently the case with the adjoining great veins, whilst the lungs are usually pale.
The syncope occasioned by some kinds of mental emotion is of the ordinary or anæmic kind, and consequently the condition of the brain must act first on the bloodvessels, and not directly on the heart. Certain persons are liable to faint on witnessing a surgical operation. Now if the mental emotion of these persons acted directly on the heart, whilst the rest of the vascular system was unaffected, the distribution of the blood would be nearly the same as in asphyxia, where the circulation is first impeded in the lungs, and is ultimately arrested by loss of power in the heart. If the action of the heart were weakened, or stopped, in the first instance, by the kind of emotion under consideration, the arteries would be emptied by their contractility and elasticity, and the blood would accumulate in the right cavities of the heart and the great veins leading to them. In a medical student fresh from the country, who is by no means deficient in blood, the jugulars would become distended and the face livid, and the recumbent posture would probably do but little towards removing the symptoms. The phenomena which are witnessed, however, indicate a very different condition of the vascular system. The person about to faint from the cause indicated, frequently becomes pale before he feels anything wrong; and when requested to retire and sit down, often says that there is nothing the matter with him. In a short time he faints, and falls, if no one catches hold of him; but the moment he is in the recumbent posture he recovers. In such a case as this, the effect of the mental emotion must be first exerted on the veins, or the veins and capillaries, through the nerves which supply these vessels; they allow themselves to become distended, and the heart ceases to act for want of its supply of blood, as in syncope from blood-letting, and anæmic syncope from any cause.
Several authors have attributed the empty state of the heart met with after death, in certain cases of fatal syncope, to want of power in the left ventricle to supply the right cavities of the heart; but this is to argue as if the blood passed out of the body after leaving the right ventricle, and the left ventricle had to supply a newly formed fluid. The effects of want of power in the left ventricle are the same as those of an obstruction at the origin of the aorta; the lungs become congested, and the right cavities of the heart more or less distended, from the blood not being able to pass readily through the lungs. Patients who die of heart disease die with the cavities of that organ full. Some patients, indeed, with fatty disease of the heart, die suddenly of anæmic syncope, and the heart is found empty; but in these cases it is evident that death is not occasioned by the disease of the heart, but by some condition of the bloodvessels which accompanies it.
Chevalier was, I believe, the first to draw marked attention to cases of sudden death arising from an empty state of the heart, in a paper in the first volume of the Transactions of the Royal Medical and Chirurgical Society; and he rightly attributed the emptiness of the heart to a loss of power in the bloodvessels. His words are as follow:—
“The disease I have now described may, perhaps, be termed asphyxia idiopathica. The essential circumstances of it evidently denote a sudden loss of power in the vessels, and chiefly in the minuter ones, to propel the blood they have received from the heart. In consequence of which, this organ, after having contracted so as to empty itself, and then dilated again, continues relaxed for want of the return of its accustomed stimulus, and dies in that dilated state.”
The word asphyxia has become so closely connected by physiologists with death by privation of air, where the symptoms and appearances are the reverse of those in Chevalier’s case, that it is necessary to discard his name of the disease which he describes, although it is etymologically correct. His cases come under the definition of what is now universally called syncope, and what I have called anæmic to distinguish it from cardiac syncope.
Chevalier speaks of a want of power in the vessels to propel the blood, and as it is not now believed that the vessels take any active share in the propulsion of the blood, this may be the reason why the views of this author have received less attention than they deserve; but it is very obvious that a want of tone in the vessels, or any great diminution of that power which enables them to support and compress the blood, is an adequate cause why the blood should be unable to reach the right side of the heart. In the case of varicose veins, previously mentioned, it was physically apparent that the cause of the syncope lay in the vessels. Disease of the arteries is well known to be usually associated with degeneration of the heart; the veins are also large and distensible in old people, who furnish the greater number of those who are liable to anæmic syncope; but the pathology of the veins, as regards both their functions and structure, is not yet sufficiently known.
Persons with disease of the heart, who die suddenly in a fit of anger, probably die always with the heart distended; that is, of cardiac syncope. Dr. Joseph Ridge, however, in his able and interesting remarks on the disease and death of John Hunter,[[134]] states his belief that that celebrated man, who had been long subject to attacks of angina pectoris, died at last of syncope, with an empty heart. He died, as is well known, during a fit of anger, and the coronary arteries were found ossified. It is not said that the heart was empty, but that it was small, and that there were no coagula in any of its cavities. It is probable that there was not much blood in its cavities, at the time of the post mortem examination, but the body of Hunter was conveyed in a sedan-chair, from St. George’s Hospital to Leicester Square, a little more than an hour after his death, so that the fluid blood would gravitate downwards. It is related that the stomach and intestines were unusually loaded with blood, and that those parts which were in a depending position, as in the bottom of the pelvis and upon the loins, were congested in a greater degree than the others; and that “this evidently arose from the fluid state of the blood.”
In syncope from muscular exertion, the cavities of the heart are distended, and its walls have occasionally been ruptured, both from violent exercise and fits of anger.
Fear probably occasions each kind of syncope in different cases. In some cases, the right cavities of the heart become distended owing to impeded respiration, and possibly to a diminution of power in the heart itself. More frequently, the syncope appears to be of the ordinary or anæmic kind, the effect of the mental condition acting first on the more distant parts of the circulation. The pallor caused by fright is proverbial.
Pain is also capable of causing both kinds of syncope. I have alluded to cases (page 55) in which the patients strained and held their breath till the pulse became intermittent, and the action of the heart was temporarily suspended by the arrested breathing; on the other hand, patients often become pale, if they are undergoing any slight operation when seated, and syncope of the anæmic kind occurs, without any previous disturbance of the respiration, but passes off as soon as they are placed in the horizontal posture. I have seen an apparently strong man faint in this manner, during the removal of a tumour from the back not larger than a nut, and where only a few drops of blood were lost. Chloroform was not employed.