An Address ON IRREGULAR ACTION OF THE HEART: Delivered at the Annual Meeting of the Kent Branch of the British Medical Association
BMJ (Clinical Research Edition)
and, whlen noticed, invariably arrests attention, lhas very generally puzzled the tllouglhtful observer. It lhas long beeni knownim that it nmy convey grave warning, or tlat miay be almiiost negligible. But, until quiite lately, it lhas not been possible to differentiate the serious from tlle iarimless varietiesof arrlhytlhinia. Thle clhief reason for this innorance lay in the fdt that ou-uis.ual m-etlhods of clinical investigation (tlio pulse, the apeki beat, an-d almost all heart sounds)
... heart sounds) refer us to tlle ventricles alomie. Tlhe in-iportance of tlle auricles was unsuspected, anid no means were atlhand wlhereby to examinle tlleir action. 2. Witlhin recent years a flood of liglht has been thrown uiponi tllis question, prinimarily by Jamues Mackenzie, wlho, wovorking with the polygraplh, -was enabled, clhiefly by a careful analvsis of thje undulations of the jugiuilar vbin, (litferentiate the auricuilar from the ventrictular contractions. This paved the way for Tllomas Lewis, whio, withi the electrocardiograpl, first demionstrated the condition klnown as fibrillatioln, and thius cleared up and explained certain points wlliclh Mackenzie's -work had left obscure. Other niames miglht.be mentioned, but it is mainly due tlle wvork of tlhese, two clinicialns, stuppleml-enting the researches of certaini anatomists and plhysiologists, tlhat ouirlknowledge of the cardiac meclhanism, bothl in lhealtlh and disease,lhas been greatly extended, and that we are Biow for tlle first timle in a position to understand and classify thle various irregtularities of tlle heart and the pulse. 3. The prognosis oflheart cases, and tlleir managemient, mlore especially as regards permission-or limitationi of effort, is anmatter of primiie iiioment to outr patients. We can lhardlv do a m-iani a worse turni tlhan tocut hiim off ,needlessly fromn hiis worlk or hlis recreation-yet to allow hiim freedom to hiis iunidoing is a still ilmore seriouss miistake. 1Few 7more difficult decisionis confront us in our.daily works annd a careful survey of all the aspects of a case slhould be mnade before a conclusion is reaclhed. 'Mistakes are often m41ade, and anytliing wliich helps us towards a right decision is of value. Th-le ability todifferentiate the variety of a putlse irregularity puts an iminportant weapon inotur liands, and one wllichl will not ilnffequently turn the scale. 4. My last reason for selecting this suibject is tlat, in addition to being new, it is far from easy, and its importance -is not univ6rsally recognizeid. Medicine is widd anid widening, and we can none of us keepp up with it a1ll round. The interest of some lhas not yet been awakened to these matters, and othlers lhave yet to realize thlat suchl terms as "sinus arryytllhmia" and "extrasystole, " eart-block and "aurinlar' fibrillation " refer, not to naew anid rare conditions, but to thh e ordinary cases of irreaularhleart actioni, withl or without valve lesion, wN,hich we meleet withl on our daily rounds. FuLrthler, the sconclusion is easily drawn that the recogniition of suchl ionditions is too complicated for thle routinie of general practice. Tile papers whlich appear in 'tle journals are ,genrally illustrated by numiierous tracinngs of the .sy3nehlronous undulationis of various blood vessels, ohtained byinlgenious appliances, withl whlichl we are most ,of us unfam-iiliar; anid thle mneaning of these tracings is not only by nao meanas self-evident, but is somiietimes revealed soly after close scruitiniy even to thle experts, whlo are, in LewNis's words.' fully conscious of the burdeni whlichi awaits the student or practitioner whio hias yet to bring I ihw-self abreast tile timiies in this field ofkonowledge "; and it is, inideed, the difficulty I hiave mnyself experienced in attelmlpting to extract the kernel from the large amountI of material now available, wlliclh lhas given me the courage to lhope tlhat, in endeavouring to put tllese matters before you in as simiple a manner as possible, I may be emplpying tlle time usefully. But the taskof reducing so technfical a subject to sinmple terms is not liglht, and in its aitemppt I feel sure I may rely upon the symiipatlhy and Stjie indulgence of tllose who lhave already muastered-its intricacies-_llI!7iods of Investiga1ti0)?. -Tllough our present knowledge of cardiac irregularities and theirsignificance could nlot lhave been arrived at witlh out the use of tlle polygraplh ancd thle elec-troceardiogiaijh, and though doubtful cases can only-be differenitiatedby recourse to these metlhods, yet, thanks mnainly to the patient labours of Mackenzie, thle. uinderlying principles can be grasped witlhout muclh difficalty,.,and typicaI examples of eaclh variety of arrb.ythmia; ian be zeienog+ nized by thle simple and.fainiliar m-ieans of t)sui-finei anid the steth6gcope. It is Tihis aspeiet of the flbj&c~t that I wish to elmplhasize to-day; but, while I do:not proposeto depart from..my aim of simplicity by referring y4ut -to diagrams and tracings, therae are one or two points ip i hbis connexion to w1kidlr-it may.be lhelpful briefly to alludeh. -_ Whlen we '"feel." the puls'e at tllewrist,.wve slobuld learn a good deal about tlhe.action of one-but only one-of tlle four clhambers of the lheart-namely, tlce-left ventricle. Further, w'e learn of it only during Ahat! perio_d'wlh&Ahe aortic valves are open-that is t-o iay, ot qulite the wliole of systole; and tlle sphyg-niogr4Vh and s;tetlioscope,though amplifying, leferius-in the' main tothe saiae pemtion ofthe ventricular: cycle. Still .while an irregularity of the pulse doubtless indicates an irregulaiity oftlie left ventricle, it does not follow that all irregularities originiate tlhere. Some do, but somiie originate in the auiricles, and otliers againi are duLe to delay in transm-lissioni of the imnptulse fromii the upper to tlhe lower chambers; and the way to find out more about aniy individual case is to take a tracinga fromn the internal juguLlar vein, from whlich weimiay learnmlEuclh botlh about the systole ancd the diastole of botlh auricles and ventricles. The " venous puLlse " is not invariably present, but it is present in mot lhearts, hlealtlhy or diseased. There is a " ventricular type" present in certain conditions wlhere tlle undulations correspondl to tllose of tlle carotid artery, but thenormnal or "auLicular type" is that from wllich we learn miost, and to the clharacteristics of tlhis tracing I wish very briefly to alluide. The contraction of the right auLricle gives, so to speak, a back-kick to the blood in the jugulars, and a wave-tlhe " auricular wave"-is produced. Later the colntraction of tlle right ventricle, stretclhing the closed tricuspid valve, or ilot uncomnmonly causinig a slight regutrgitation througlh it, gives a secondc back-kick and produces a "-ventricular wave." Again, theproximity of the carotid artery gives a third or "carotid wave," whlich, in point of timte, comes between the other two. .-In this tracing,tlhen, we get a direct record f-om three different chamb6rs of thlle heartthe rightauricle and both ventricles. Muc-li skill is needed in interpreting some of these records, for it will be obvious that in varying types of irregularity the clharacters oftlhese various waves and thle spacing between them will vary, and synchronous tracings fromtlle lheart itself or from an artery are commonly needed to point out whichl wave is which.