The nomenclature to be desired is one which would assign different distinguishing names to each variety of coagulum, so that at once its origin, mode of formation, and perhaps too its age, should be exactly determined. The ancients employed the term polyp for deposits of every description in the heart, but such use of the word was, generally speaking, erroneous, since the true polyp is a very rare disease of the cardiac cavities. Bartholetti and Pissini first made use of it, and considered without doubt that the false polyps or fibrinous deposits in the heart were of analogous nature with the true polypi which are found so frequently in the uterus and nasal cavities. No doubt (as has been inferred) the term polyp in regard to these formations came into habitual use owing to lack of familiarity on the part of the older writers with the varied aspects of clots, as well as their ignorance of the distinct appearance offered by sections from them under lenses of great power. This mistake, therefore, is to-day not to be wondered at, if we duly consider how imperfect and unusual in olden times were pathological researches. Heart-clot was, as will be seen in the historical sketch which follows, the subject of numerous prolonged and animated discussions. As a result of these latter, it was ultimately believed that the great differences of appearance and formation which exist between coagula depend in great measure upon their relative age, and it is for this reason that the basis of distinction between their varieties rests mainly upon the period of time previous to a death at which they are formed. When we speak, however, of polypiform concretion or deposit, we approximate nearer the truth and indicate in a measure the local origin of a coagulum. Many others have employed the terms post-mortem and ante-mortem as being the only suitable terms with which to make a distinction between the coagula formed during active existence and those which are revealed only with the scalpel in the dead-house. In the consideration of this subject the symptoms shall be fully described which indicate the presence of heart-clot found during life, whilst in regard to clots formed in extremis or after death it is desirable particularly to show the pathological characters which shall definitely place them. For all that pertains to embolism of the heart we shall refer the reader, except when it is essential to mention certain details, to other articles in this work. Certain authors have erroneously, it is believed, regarded this subject of heart-clot as one of mere pathological interest, stating that the dead-house is the only place to study its origin and many of its organic effects. This opinion should be combated with vigor. Such a view is far too restricted, and it is here believed that the clinical aspects of cardiac thrombosis are worthy of attentive study, and that something better and further should be attained than merely to watch the downward course of a patient thus affected, and to bear in mind the pathological sequelæ of this disease.
HISTORICAL SKETCH.—The questions which have a present interest in regard to heart-clot are very different from those which formerly engaged medical attention. No longer are we uncertain as to the formation of these coagula during life, nor doubtful as to the various and important effects produced by their transport in different organs through the arterial and venous vessels. Thanks especially to the inaugural thesis of Legroux (1827), to those of Le Marchand and Ball (1862), to that of Bucquoy (1863), but particularly to the experimental researches of Virchow (1846–56) and to the observations of Senhouse Kirkes1 in regard to the formation and transport of emboli into the cerebral vessels, these facts are all matters of ordinary information. There is little doubt that Galen had noted the formation of intra-cardiac thrombi during life, and attributed to them interference with circulation and respiration, and, at times, sudden death. With the exception of Salius, mentioned by Morgagni as having remarked oedema due to this cause, we reach the sixteenth century before again meeting with any detailed mention of a similar pathological condition. Helidé of Padua, according to some,2 Benivenius, according to others,3 were the first authors to give full descriptions of cardiac polyps. This, indeed, was the term affixed for a long period to fibrinous concretions in the heart, beginning with Sebastian Pissini (Milan, 1654), who first employed it. The name took origin, without doubt, on account of their resemblance to polyps of the nasal fossæ, and perhaps to the animal thus named. It was particularly at this period that they acquired their significance, and became the subject of animated discussions between distinguished physicians of the last two centuries. Some, exaggerating their importance, attributed to them the gravest and most important symptoms, although a chronic affection of the heart or lungs present at the time was frequently sufficient to explain them; others, like Kerkring (1670) and Jos. Pasta4 (1737), who contested the possibility of the blood coagulating during life, and believed they were invariably cadaveric formations, took from them even a pathological interest. This latter extreme opposition to reality originated very soon a mixed conviction, which was that held by Senac and Morgagni. These distinguished observers recognized that intra-cardiac thrombi formed both during life and after death, the former being rarely encountered. The later, or anatomical school, confirmed these views, but also added testimony to show that ancient and terminal concretions were not phenomena of such unusual occurrence as had been previously held. Testa (1810) and Kreyssig (1824) connected fibrinous deposits with inflammation of the heart, and the last-named writer described a disease which he named carditis polyposa. This view and that of Laennec, which attributed globular vegetations to an inflammatory cause, are in our day disproved. Amongst those authors who rendered certain the formation of cardiac clots during life, we should mention a few others whose names have a special importance in this connection as having made a special study of diseases of the central organ of circulation. These are Corvisart, Burns, Andral, and Bouillaud. Since this period the field of research has become far less limited, and investigations have been made in regard to similar coagulations in the large vessels of the body.
1 Med.-Chir. Trans., 1844, pp. 281–325.
2 Dict. de Méd. pratique, vol. viii. p. 558.
3 Ziemssen's Cyclopædia, vol. vi. p. 292.
4 Quoted by Grisolle, Pathologie interne, Paris, 1865, p. 464.
In 1856 a new era was established in regard to these formations, and especially with reference to their transport. Virchow at this period showed conclusively, after long-continued and accurate clinical observations and experimental researches, that a clot formed on the one hand in one of the large veins might be carried to the pulmonary artery and block up more or less completely the supply of blood to the lungs; on the other, that a portion of a thrombus formed in the left heart-cavity might become detached and plug completely one of the arteries of some far-removed organ, as the spleen or kidney, and thus give rise to those ultimate effects which we now understand under the name of infarction. Thus was first established the new pathological ideas which have become familiar with the words embolus and embolism. True it is that Virchow was not the first writer who had described the facts relating to the translation of portions of coagulum from one region to another of the circulatory system, and its fixation in a particular arterial branch. Already this subject had been clearly and succinctly narrated by Van Swieten. A passage in which the causes and mechanism of apoplexy are referred to gives lucid explanation of this doctrine: "Whatever causes change the blood, lymph, and the matter which supplies the spirits, so as they cannot pass freely through the arteries of the brain, but are there impacted. Such are frequently—polypous concretions in the carotid and vertebral arteries, whether first formed about the heart or within the cranium itself."5 These ideas of Van Swieten had not, however, produced any very permanent impression, and were almost forgotten, when Legroux (1827) promulgated his view in regard to the possibility of portions of coagulum being carried from the heart into different portions of the arterial system. He published, in fact, two most interesting cases of gangrene of the hand and forearm in which the efficient cause of the disease was found in an obliterating embolus of the brachial artery, which was evidently similar in its nature to the thrombus found in the heart of his patient. It is interesting to remark that Legroux's inaugural thesis, in which these facts were brought to light, was only the forerunner of some very complete articles on the subject of cardiac and vascular concretions, in which he goes over much of the ground which was covered in Germany by the work of Virchow. Legroux published his ulterior researches in the Gazette hébdomadaire, Paris, 1856, pp. 716 et seq. In fact, under the head of correspondence we find in No. 20 of the journal of this year (pp. 349 and 350) an interesting letter from Legroux to the editor, in which he claims for himself the priority of publication (Van Swieten excepted) of the facts pertaining to intra-cardiac thrombi and their effects due to transport of detached fragments into a region more or less removed from their place of development (p. 34). As this claim, according to my researches, appears justified, a part at least of the credit awarded to Kirkes, Virchow, and Schützenberger as discoverers and disseminators properly belongs to Legroux.
5 G. Van Swieten, Commentaries upon the Aphorisms of Boerhaave, Aph. mx., vol. iii. p. 159, ed. London, 1774.
In spite, however, of these investigations, and those of Allibert (1828), Louis (1837), Baron (1838), and Paget,6 who showed how the blood could coagulate in the heart and by transport block up the pulmonary capillaries, we cannot dispute the glory to Virchow of having in some sort created this study. Owing to his great sagacity, he was able to seal his studies and experiments with the stamp of a master-mind. The new words embolus and embolism introduced by him refer to a process which was previously but badly understood, and which now fix, as it were, a domain in modern pathology. The theory of Virchow found many advocates—many who were opposed to it in the beginning. In consequence of this it was the origin of numerous works undertaken in this new direction. Amongst the most important are the communication of Schützenberger,7 the thesis of Lancereaux (1862), the great work of Cohn (Berlin, 1862), the article of Weber in the treatise of Pitta and Billroth—which contains recent theories about coagulation of the blood and the transformation of clots—and the memoir of Polaillon upon cardiac embolism (Paris, 1879).
6 Med.-Chir. Trans., 1844, pp. 162–188.