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Un dee symboias sulvants spparaftra sur ia darnlAre image de cheque microfiche, selon ie caa: la symbols -^> signifie "A SUiVRE". ie symbols ▼ signifie "FIN". IMaps, plates, charts, etc., may be filmed at different reduction ratios. Those too ierge to be entirely included in one expoaura ara filmed beginning in the upper left hand corner, left to right and top to bottom, aa many framea aa required. The following diagrama illustrate the method: Les cartee, planchea, tableaux, etu., peuvent Atre fllmte A dee taux de rMuction diff Arents. Lorsque le document est trop grand pour Atra reproduit en un seui cllchA, ii est f ilmA A partir de I'angie supArieur gauche, de gauche A droite, et de haut an bea, an prenant la nombra d'ifnages nteessaire. Les diagrammes suivants iilustrant ia mAthoda. 1 2 3 1 2 3 4 5 6 ,. THE PEAOTITIONEE. FEBRUARY, 1890. )rigutal Commumtations. HEART-BEAT AND PULSE-WAVE. BY C. S. ROY, M.D., F.R.S., Professor of Pathology, AND J. G. AD AMI, M.A., M.B , Demonstrator of Pathology, in the University of Cambridge. [From the Cambridge Pathological Laboratory^ The clinical importance of an exact understanding of the meaning of graphic records of the heart and pulse, together with the fact that the graphic method is the most convenient for investigating certain physiological and pathological questions connected with the circulatory system, have induced us from time to time to make a few observations on the matters expressed by the title of our paper. In these observations we have employed various new instruments, which must be described in order that our tracings may be comprehended. We will try, however, to say as little about the methods as is compatible with giving a reasonably intelligible account of our results. These results, we believe, are of a kind which will be found of value at the bedside, although to make them clear it is The Pbactitioneu. — Vol. xmv. No. 2. G 82 HEART-BEAT AND PULSE-WAVE. necessary for us to refer to some matters which at first sight may seem to be of interest to the physiologist only. It will be most convenient to consider the heart-beat first, for the simple reason that the characteristics of the pulse-wave are due for the most part to the manner in which the ventricular contraction takes place. Graphic records of the heart-beat may be obtained in a variety of ways. The contraction and expansion of the muscular wall of the ventricle or auricle, for example, may be recorded. It is possible, also, to obtain a curve of the changes in the intra- ventri- cular pressure, as was done by Chauveau, Marey, and others, and more recently and accurately by Rolleston. The changes in the diameter of the ventricles, both in the antero-posterior and in the transverse direction, may be graphically determined : and the movements of the apex can in like manner be investigated. We may obtain curves of the contraction and expansion of the musculi papillares, showing the movements of the free edges of the auriculo-ventricular valves. Or again we may register the changes in volume of the heart as a whole. The kinds of tracings which we have just mentioned are perhaps among the most important of those by which the characters of the heart- beat can be studied, although there are many others which need not here be referred to. SECTION I. CONTRACTION-CURVE OF THE VENTRICULAR WALL. Let US consider first of all the curve of contraction and ex- pansion of the heart-muscle forming the ventricular wall. In order to obtain trustworthy tracings we must employ a method which will not hinder the movements of the heart as a whole. The method must also give tracings which will not be aflfected by these movements. Tht ' myocardiograph ' (as we may call it to distinguish it from other forms of cardiograph) shown some- what diagrammatically in Fig. 1, fulfils these conditions. By its means it is easy to obtain trustworthy graphic records of the variations in the distance apart of any two points on the surface of the heart-wall. Its construction is as follows: The light MEAUT-BEAT AND PULSE-WAVE. 8.3 Fig. 1.— Myocardiograph for mammalian heart shown semi-diagrammatically. The light vertical rod a, which for convenience of space is shown shortenec in the figure, is slung from the pivots which are represented in section as seen from above in B. This arrangement allows the rod a to swing freely, the centre of rotation being the small hole at h (in B). The lower end, c, of this rod is fixed to the surface of the heart-wall as seen in the figure. To obtain tracingsof the heart-wall, the small hook d is inserted in the visceral pericardium at a convenient distance from the end of the rod a. To this hook is attached a strong silk thread e, which after passing round the light grooved pulley /is conveyed upwards through the small hole b to the lover g, being kept taut by the fine rubber thread h. To obtain tracings of the contraction of the miisculi papillares, the fine hooked wire i is inserted through the auricular wall ami hooked over one of the mitral flaps. It slides easily in the collar k, which is tied to the edges of the opening in the auricular wall. To this is attached the thread I, which after passing round the light pulley m is conveyed upwards through the hole b to the lever ?i, being kept taut by the rubber thread o. G 2 84 HEART-BEAT AND PULSE-WAVE. wooden rod (a) is slung on pivots or gimbals (h), somewhat after the manner of the ordinary mercurial barometer used on board ship. The lower end (c) of the rod is fixed to the heart- wall at any desired point by means of a thread which has been passed under a fold of the visceral pericardium. The end of the rod, from the manner in which it is slung, can follow the complicated movements of the heart without hindering them. Projecting from the rod near its lower end is thehorizontal arm (p), which carries at its extremity a light vulcanite grooved pulley (/). Round this latter runs a strong silk thread (e), which is attached to a minute metal hook (d) fixed in the ventricular wall at any desired distance from the end of the rod (a). After passing round the pulley, the thread is carried upwards through a small hole (b) placed at the centre of rotation of the rod, as can be seen from the sketch elevation of the pivoting arrangement B in Fig. 1. From this hole the thread goes upwards to the recording lever (g), being kept taut by a fine indiarubber spring (A). The object of passing the thread through the hole at the centre of rotation of the rod is to allow free movement of the end of the latter with the heart, to which it is fixed, without any pull on the recording lever being thereby produced. The position of the lever is altered only by alterations in the distance between the point where the hook is fixed, and the point to which the rod is tied. It need hardly be added that in order to make use of this, instrument the heart must be exposed by making a " window " in the thorax, the animal (a dog in our experiments) being cur- arised as well as anaesthetised, and the respiration being, of course, carried on artificially. On the myographic curve of the auricular wall we do not propose to say anything here. The curves which are represented below in this section of our paper were obtained from the wall of the left ventricle, although, as they diflfer in no essential particular from curves obtained by the same method from the right ventricle, it must be understood that what we have to say about them applies equally to the two ventricles. The myographic curve from the ventricular wall varies somewhat in character according to the relative position of the two points to which the instrument is attached. Let us con- sider first the curve given by this method when the two points on HEART-BEA T AND PULSE- WA VE. 85 lie in a line running from base to apex, and more or less parallel Fig. 2. therefore with the interventricular sulcus. This, for con- venience sake, we may call the " longitudinal curve " of the 86 HEART-BEAT AND PULSE-WAVE. ventncular wall, to distinguish it from that ohtained from a part lying between two points on any line runniig round the ventricles, parallel to the auriculo-ventricular sulcus, which may similarly be termed the " transverse ventricular " curve. The carves (A, B, C) shown in Fig. 2 are examples of tracings registering the contraction between two points in the middle third of a liue joining the base and apex of the left ventricle at some distance from the ventricular septum. The illustration shows three diflferent tracings, in all of which a rise of the record- ing lever corresponds to contraction of the ventricle wall, and a descent to expansion. The contraction begins, then, in each at a. It can be seen that the heart-wall contracts at first rapidly, until the shortening is suddenly arrested at the point h, the height of which on the ascending line varies under different conditions. In curve A (Fig. 2), it is low down, near the com- mencement of the ascent ; in curve B it is about half-way up ; while in curve C it is near the top. This arrest of the contrac- tion is often followed by a certain degree of expansion, producing a more or less well-marked notch at c. On the other hand, it may (as in Fig. 4, A) be followed by a simple cessation of the contraction, or even by mere slowing, though this, according to our experience, is unusual. After the notch at c, the contraction continues, but is more slow than before. What is the cause of this interruption of the shortening ? We at first thought that it must be due to the tightening of the auriculo-ventricular valves as a result of the rise of the intra-ventricular pressure, produced by the contraction of the heart-wall. That it results from something: more than this will be seen when we come to compare the curve of contraction of the musculi papillares with that of the heart-wall itself. . We need only remark here that the time between the com- mencement of the contraction of the heart- wall and this break in the shortening varies under varying conditions, all of which how- ever affect the amount of blood contained within the ventricle at the commencement of systole. The greater the expansion of the heart in diastole, the sooner does this break in tha ascending line of the contraction curve follow its commencement, and vice versd. The part of the curve from c to d shows that the heart contracts more slowly at that part than it did at the beginning of systole. As V HEART-BEAT AND PULSE-WAVE. 87 i given above enables us to divide the ventricular systole into five more or less distinct phases. I- — During this phase the ventricle wall is contracting, but the musculi papillares are at rest (a to b, Figs. 2, 3, 4). II. — During this the papillary muscles carry out the first rapid part of their contraction, accompanied by slowing, arrest, or retrogression of the shortening of the fibres of the heart-wall, which is most marked in tracings taken along a line running around the heart transversely (6 to c Figs. 2, 3, 4, 5). Ill- — During this the shortening of the papillary muscle is considerably less rapid than during the last phase; the fibres of the heart-wall are also being shortened, although much more slowly than during the first part of its systole (c to d). IV. — During this phase both papillary muscle and ventricle- wall remain contracted, but do not undergo further shortening (d to c^'). v.— During this period the papillary muscle expands rapidly, while the ventricle-wall remains contracted (d to e). This last phase belongs both to systole and diastole, the ex- pansion beginning in the papillary muscles. The diastole of the heart-wall may be divided into three phases, namely : — I- — During this expansion takes place rapidly, and with fairly uniform rapidity (e to/). II. — This phase is only well shown on the curves when the amount of blood available to permit the ventricle to expand is not great, so that the expansion becomes slowed or even arrested after the first elastic expansion of the ventricles has drawn into them the greater part of the available blood (/ to g, Fig. 2, C and 5 A). III. — During this phase the wave of blood which results from the contraction of the veins and auricles reaches the ven- llH M l,il l >I I. J 94 HEART-BEAT AND PULSE WAVE. ♦ricular cavity, and causes or allows the final expansion of the ventricular wall which precedes systole (g to a). It will be observed that we have said little or nothing as yet as to the absolute or relative duration of these eight phases of the ventricular cycle. The reason of this is that the relative duration is not by any means a fixed one, and the subject can therefore be best considered when we come to speak of the influences which vary the character of the heart-beat. (To he continued.)