On the pathology and treatment of valvular disease of the heart and its secondary affections : being the Gulstonian lectures, delivered at the Royal College of Physicians in February 1851 / by Edward Latham Ormerod.

  • Edward Ormerod
Date:
1851
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Licence: Public Domain Mark

Credit: On the pathology and treatment of valvular disease of the heart and its secondary affections : being the Gulstonian lectures, delivered at the Royal College of Physicians in February 1851 / by Edward Latham Ormerod. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the first kind. With this, however, be- yond the mention, we have here nothing to do; the altered conditions of the blood, and its containuig vessels, alone falHng within the scope of the present remarks. It appears that purring tremor may be produced immediately in healtliy animals by large depletion.* It might be referred, imder such circumstances, to imperfect distension of the vessels. Tliis tremor, liowever, thus produced, not only con- tinues, but increases in intensity in the com'se of a short time : but we know, from Dr. Gr. O. Eees' observations,t that the quantity of blood abstracted by vene- section is rapidly replaced by absorption of water. We must therefore consider ex- treme attenuation of the blood as at least as powerful a predisposing cause of this sign as an imperfect distension of the blood-vessels can be. Certainly it is a caiise in more durable, ana* probably in more frequent operation. Now, obviously, no fluid could commu- nicate this sensation to our ears or hands when perfectly at rest. We can admit the attenuation of the blood only as a predis- posing cause of pui'ring tremor. We look for the exciting or proximate cause in the movements of the circulation. In the ex- periments just alluded to the tremor was produced in healthy animals. Applying tliis to practice, even if all clinical expe- rience were opposed to the statement (which it is not), we must admit that pm-- ring tremor does not necessarily imply the existence of organic disease ol' the blood- vessels, but that the movements of, or in- duced by, healtliy circiilating organs are capable of producing it in a subject so predisposed. We must admit that blood attenuated to a certain degi'ee is capable of being thrown into vibration—to use this more general expression—by causes insuffi- cient to affect healthy blood after such, a manner—namely, by the ordinary move- ments of the circxdation: but it requires unnatural agitation to throw normally-con- stituted blood into such a state of vibra- tion ; and, more than this, it is required that the fluid pressure shall be less at the point where the vibration manifests itself than elsewhere. J * Hope on Diseases of the Heart, p. 100, 3d edition. * t Gulstonian Lectures, Medical Gazktte, 1845, p. 851. ' ± We are indebted to Dr. Corrigan (Dublin Journal, vols. X. and xiv.) for a verv clear ex- planation of the mode of pi eduction of this curious phenomenon. Of the correctness of the iinriciple advocated any one may easily satisfy umself, by repeating- the very simple experiments )y which Dr^ CorriKan supports his theory. A :ube of metal, or animal membrane, through which a stream of water is running, is to be con- itncted at one point, so that the egress of the Botli these requisite conditions of tho circulating fluid are found imdcr the cir- cumstances where piu'ring tremor is usually produced. The contracted aortic opening, for instance, does not allow of the imme- diate equahsation of pressure of the blood in the ventricle and in the aorta ; and the same physical impediment which causes this, causes also unnatural disturbance of the current of the circulation. So it is also in many cases of mitral, or more espe- cially tricuspid regurgitation, where the blood runs under pressure from the ven- tricle into the dilated and nearly fitlly distended auricle. So, again, these condi- tions are present in an aneurism al varix; the opening from the arteiy into the vein supplying the means whereby the current of the circulation is disturbed, and the fluid pressure is rendered unequal. On such principles the occurrence of pm-ring tremor under certain cii'cumstances may be explaijied. But why is it not always found under these circiunstances ? Why, for instance, does it not occur always with sigmoid regurgitation, or, indeed, during the filUng of the ventricles of the healthy heart ? A very sufficient answer lies in the fact that, under ordinary cir- cumstances, the blood is not in a condition to be tlu'own into such a state of vibration by those movements. Eut, apart from this, I think that these apparent exceptions illustrate a vej-y important point in tlie ex- planation of the mode of production of purring tremor, on wlu?h it will be of inte- rest briefly to dwell. In both these instances one condition of the containing vessels is wanting. Re- garding the pm'ring tremor simply as a vibration, whether of the blood, or vessels, or both, obviously some degree of tension of the parts concerned is requisite for its fluid from the lower portion of the tube may be freer than its ingress. In the previously silent stream of fluid, now, below this point, a loud murmur with purring tremor will become mani- fest. Constrict the tube in a second place, at a lower point, and the murmur and the tremor will both cease over the interspace, as soon a» the equilibrium of pressure shall have been re- stored on each side of the point first constricted. In the same able essays Dr. Corrigan enter* very particularly into the conditions requisite for the production of a murmur. But in all diffi- dence I must here venture to withhold such com- plete assent to bis conclusions. The theory does not appear to me so beautifully and closely applicable to murmurs, as to purring tremor. At le: St the conviction of its truth is not so forcibly impressed by the examination of each ca.se of endocardial murmur, as it is by that of each case of purring tremor. Probably, as Dr. Williams (Dis. Chest, p. 217) remarks, the flaccid tube only receives the sound or tremor from the point of stricture, as the tube of a trumpet does that from the lips. It is an instrument neces- sary for the manifestation of the grosser sign, the tremor, but not for that of the more delicate sign, the murmur.
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