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To A. D. 
 
I 
 
 i 
 
THE 
 
 Heart Rhythms 
 
 PAUL DUDLEY LAMSON, M.D. 
 
 Associate Professor of Pharmacology 
 Johns Hopkins University 
 
 BALTIMORE 
 
 WILLIAMS AND WILKINS COMPANY 
 
 1921 
 
dT- S- 
 
 I -y —! O f ^ 
 
 Copyright 1921 
 WILLIAMS & WILKINS COMPANY 
 
 Made in United States of America 
 
 All rights reserved, including that of translation 
 
 into foreign langtiages, including 
 
 the Scandinavian. 
 
 
 COMPOSED AND PRINTED AT THE 
 
 WAVERLY PRESS 
 
 By THE Williams & Wilkins Company 
 
 Baltimore, Md., U. S. A. 
 
CONTENTS 
 
 Introduction 7 
 
 PART I 
 Chapter I 
 
 THE DEVELOPMENT OF OUR KXOWT-EDGE OF THE HEART RHYTHMS 
 
 The pulse I3 
 
 The sphygmograph 14 
 
 The polygraph 16 
 
 The electrocardiograph I9 
 
 Ch.^ter II 
 
 FIVE DIPORTAXT ELEMENTS OF THE HEART BEAT 
 
 1. The simultaneous contraction of both auricles and both ventricles 24 
 
 2. The rhythroicity of beat of cardiac muscle 26 
 
 3. The impulse for contraction occurs at the point of greatest irritability. . . 26 
 
 4. The refractory period of the ventricles 27 
 
 5. The conduction of impulses from auricle to ventricle 27 
 
 Summary 29 
 
 Chapter III 
 
 THE DIVISION OF THE HEART INTO FUNCTIONAL AREAS BY MEANS OF THE 
 ELECTROCARDIOGRAPH 
 
 1. The sino-auricular node 32 
 
 2. The auricular- ventricular node and bundle 33 
 
 3. The auricular musculature 33 
 
 4. The ventricular musculature 33 
 
 Chapter IV 
 
 THE CLASSIFICATION OF THE HEART RHYTHMS ON THE BASIS OF POINT OF 
 ORIGIN OF lilPULSES 
 
 I. Sino-auricular rhythms 35 
 
 1. The normal heart beat 36 
 
 a. Simple tachycardia 36 
 
 b. Simple bradycardia 36 
 
 c. Sinus arrhythmia 37 
 
 2. Ectopic beats interrupting the normal heart beat 37 
 
 a. Ectopic auricular beats 3/ 
 
 b. Ectopic auricular ventricular nodal beats 39 
 
 c. Ectopic ventricular beats 40 
 
 II. Ectopic auricular rhythms 41 
 
 1. Paroxysmal tachycardia 42 
 
 2. Auricular flutter 43 
 
 3. Auricular fibrillation 45 
 
 5 
 
6 CONTENTS 
 
 in. Auricular ventricular nodal rhythms 48 
 
 rV. Ectopic ventricular rhythms 49 
 
 Summary of ectopic rhythms 51 
 
 Chapter V 
 
 ABNORMALITIES OF CONDUCTION FROM AURICLE TO VENTRICLE 
 
 1. Increased conduction time 52 
 
 2. Dropped beats or partial block 52 
 
 3. Complete block or idio-ventricular rhythm 52 
 
 PART II 
 Chapter I 
 
 INTERPRETATION OF THE ELECTROCARDIOGRAM 
 
 Chapter II 
 
 THE POLYGRAPH, SPHYGMOGRAPH, AND PULSE 
 
 Instruments 64 
 
 The radial pulse 69 
 
 The venous pulse 72 
 
 Chapter III 
 
 POLYGRAPHIC CURVES 
 
 I. Sino-auricular rhythms 83 
 
 a. The normal heart beat 83 
 
 b. Simple tachycardia 83 
 
 c. Simple bradycardia 83 
 
 d. Sinus arrhythmia 83 
 
 II. Ectopic beats interrupting normal rhythms 85 
 
 a. Ectopic auricular beats 85 
 
 b. Ectopic auricular- ventricular nodal beats 85 
 
 c. Ectopic ventricular beats 86 
 
 m. Ectopic auricular rhythms 87 
 
 a. Paroxysmal tachycardia 87 
 
 b. Auricular flutter 87 
 
 c. Auricular fibrillation 89 
 
 IV. Auricular-ventricular nodal rhythms 89 
 
 V. Ectopic ventricular rhythms 91 
 
 VI. Abnormalities of conduction from auricle to ventricle 91 
 
 a. Prolonged conduction time 91 
 
 b. Dropped beats or partial block 91 
 
 c. Complete block or idio-ventricular rhythm 93 
 
 Summary of polygraphic tracings 93 
 
 Summary of sphygmographic tracings 95 
 
 Construction of diagrammatic curves 96 
 
INTRODUCTION 
 
 The object of this book is not to present anything new in 
 regard to the cardiac rhythms, but to separate them from 
 the intricate mass of information concerning instruments, 
 curves, cardiac physiolog>% etc., in which they are often 
 buried, and to consider the rhythms themselves as a whole, 
 and in relation to each other, but apart from all other func- 
 tions of the heart. In doing so they stand out as a very 
 simple and definite mechanism, which when once understood 
 can never be forgotten. 
 
 The general plan of this book was developed in 1912 
 after studying in London, was used in the next year in 
 teaching at the Peter Bent Brigham Hospital, Boston, 
 and since then in connection with lectures in pharmacology 
 at Johns Hopkins University. On account of various re- 
 quests during the past ten years to publish this plan of the 
 heart rhythms the book has finally been completed. 
 
 The lack of a clear understanding of the rhythms of the 
 heart among well informed clinicians and students is quite 
 surprising but easily accounted for. The subject is of 
 fairly recent development, only a \-ery meager knowledge 
 being had before the advent of the electrocardiograph in 
 about 1910. Up to this time the polygraph was used by 
 a few people and it was possible for even the most experienced 
 to interpret only a part of their curves, and the whole sub- 
 ject was entirely out of reach of the busy practitioner. The 
 electrocardiograph cleared up the heart rhythms at once. 
 It is this fact which has been generally overlooked, and which 
 makes such a book as this possible. The subject of heart 
 physiology is of course in its infancy, as is the cause of the 
 
 7 
 
8 INTRODUCTION 
 
 heart beat, etc., but the rhythms of the heart as such are 
 simply the time relations of contractions of auricles and 
 ventricles and these have been satisfactorily worked out. 
 
 It is now possible to present a diagrammatic scheme of the 
 heart divided into four areas from which impulses for con- 
 traction can arise. As these areas comprise the entire 
 heart, no other points of origin of impulses can exist. A 
 scheme of heart rhythms on the basis of point of origin of 
 impulses can then be worked out which must include all 
 rhythms. Given a few (five) functions of cardiac muscle, 
 rhythms may be calculated by a mathematician with no 
 other knowledge of the heart. There will be a limited 
 number of rhythms, and each of them has been found to 
 occur chnically. With such a scheme it is impossible to 
 forget the rhythms as they can always be worked out. Any 
 curve or tracing obtained from a patient can be referred to 
 this process of analysis, and can be classified at once. 
 Finally one has a clear mental picture of the limits of cardiac 
 rhythms and will not waste time over each new curve 
 imagining that he has some totally new rhythm. 
 
 The clinical value of a knowledge of these rhythms is 
 of far greater importance than those not understanding the 
 rhythms reahze. The actual diagnosis cannot be made with- 
 out the use of an instrument, in many cases by the electro- 
 cardiograph only, which is a cumbersome, expensive and 
 complicated instrument quite out of reach from a financial 
 point of view of the general practitioner, but which should 
 be part of the equipment of every hospital. The polygraph, 
 a small portable instrument, can however be used by anyone, 
 and should come into more general use. It is of absolutely 
 no value -without a complete knowledge of the cardiac 
 rhythms. The reason for this is that the polygraph gives 
 no characteristic curves for the auricle and an interpreta- 
 
INTRODUCTION 9 
 
 tion can be made only by careful plotting of time relations, 
 while in the electrocardiogram the auricular and ventricular 
 impulses are shown by complexes of characteristic shape 
 and can be recognized at once. Besides this in many cases 
 only incomplete information can be obtained by a poly- 
 graphic tracing and a diagnosis made by exclusion only, 
 which is impossible when the limit of rhythms is not defi- 
 nitely known. The instrument is much harder to use in- 
 telhgently than the larger electrocardiograph and the cup- 
 boards of many a practitioner probably hold one of these 
 discarded machines. An intelUgent understanding of the 
 rhythms themselves apart from other heart functions, 
 instruments, and curves, gives one a basis on which to reason 
 out a case, and will allow every practitioner to treat his 
 patients more intelligently whether the diagnosis is made 
 from feehng the pulse, taking a sphygmographic or poly- 
 graphic tracing, or an electrocardiogram. 
 
 The book is divided into two parts. It is hoped that 
 the first will be found readable, and from it one can obtain 
 an intelligent understanding of the heart rhythms. In the 
 second part a very brief outline of the electrocardiograph 
 and the taking of electrocardiograms is given. It is 
 assumed that anyone using such an instrument would 
 require a much more detailed knowledge than the scope 
 of this book allows. 
 
 The polygraph however is taken up at length. With a 
 clear understanding of the heart rhythms, this instrument 
 is of great clinical importance, and is well worth a careful 
 study. Its use requires care, and as ma,ny curves can be 
 diagnosed by exclusion only it is essential to have a 
 knowledge of all the rhythms before a diagnosis can be 
 made. Although this requires considerable careful study 
 it is hoped that the pointing out of the few essential 
 
10 INTRODUCTION 
 
 factors necessary for the taking of a curve, here given, will 
 simplify this apparently complex subject. 
 
 References, names of authors and investigators, have 
 been left out to avoid confusion. The book is written 
 with the purpose of arranging the great mass of informa- 
 tion which has grown out of years of work by many in- 
 vestigators; and presenting it in as concise a form as 
 possible in order that it may be more widely used in the 
 study and treatment of those suffering from disorders of 
 the heart. The student or reader who wishes to go 
 further will find each phase discussed in detail in many 
 excellent books on the subject. 
 
 I wish here to express my thanks to the Arthur H. 
 Thomas Co. and The Cambridge and Paul Instrument 
 Company, Limited, for their courtesy in allowing me to 
 use cuts of their instruments. 
 
 P. D. L. 
 
 Baltimore, August 1, 1921. 
 
PART I 
 
CHAPTER I 
 
 The De\^lopment of Our Knowledge of the Heart 
 
 Rhythms 
 
 the pulse 
 
 Probably the first interest in heart rhythms came from 
 "taking the pulse." This usually meant feeling the pulse 
 wave in the radial artery at the wrist, and we find very 
 early records of fast, slow, and irregular pulses, but these 
 were taken as signs of the patient's condition and little atten- 
 tion was paid to the reason for and the mechanism of their 
 production. The pulse was easily felt and gave the physi- 
 cian perhaps as much information as any single examination 
 does. B}' it he was able to tell whether the heart were 
 beating regularly or irregularly, fast or slowly, whether 
 each beat were large and forcible, or small and weak, and 
 whether beating against the normal, high or low pressure. 
 It was an import ant examination, b ut did not explain the 
 cause of these different rhvthms . If we represent the 
 circulation as in figure 1 it will be seen that the radial pulse, 
 or any other arterial pulse, is a direct index of left ven- 
 tricular contraction only, as this is the one heart chamber 
 pumping blood into the aorta, the right auricle emptying 
 into the right ventricle, the right ventricle into the lungs, 
 and the left auricle into the left ventricle. A study of the 
 pulse alone gives then no idea of what the auricles are doing, 
 but, as we shall see later, when the relationship between 
 ventricular and auricular contraction is once understood, 
 it is possible to infer by feeling the pulse what is going on 
 in the auricles, so that a knowledge of the i:)ulse is at present 
 even more valuable than before. 
 
 13 
 
14 
 
 THE HEART RHYTHMS 
 THE SPHYGMOGRAPH 
 
 The first careful study of the pulse was made by using 
 an instrument called the " sphygmograph, " with which the 
 pulse waves could be recorded (see fig. 2). This was done 
 by placing a tambour with a rubber membrane, in the center 
 of which was a button, on the wrist in such a manner that 
 the button pressed on the radial artery. This tambour 
 
 /\oria and Adenal Pukes, 
 
 Fig. 1. Diagrammatic representation of the heart showing that the arterial 
 pulse is an index of left ventricular contraction only. 
 
 was connected by a rubber tube with a second tambour, 
 to which a lever recording on a smoked drum was attached. 
 Each pulse wave compressed the air in the tambour, and 
 transmitted this wave to the lever, which recorded the pulse 
 in a continuous curve. The time was also recorded, usually 
 in one-fifth second intervals. Such a sphygmographic 
 curve is shown diagrammatically in figure 3. With this 
 instrument the time of left ventricular contraction could 
 
DEVELOPMENT OF KNOWLEDGE OF HEART RHYTHMS 15 
 
 be recorded very accurately. The shape of the curve had 
 Httle significance as it depended on the instrument used, 
 and its adjustment to the UTist, but two points in the curve 
 
 Fig. 2. Showing the principle of the sphygmograph. The tambour placed 
 over the radial artery transmits an air wave to the tambour and recording lever 
 which records the pulse wave on the revolving drum. A time marker is shown 
 which is essential for the interpretation of these curves. 
 
 were found to be of great importance: the first of these 
 (1) the beginning of the upstroke, being an index of the 
 beginning of left ventricular contraction, and the "dicrotic 
 notch" (J)|(a!^discussion of which will be found on page 
 
16 
 
 THE HEART RHYTHMS 
 
 (69) marking the end of contraction. The end of the 
 upstroke {2) has no significance, as it depends upon the 
 inertia of the lever. If a hght dehcate instrument is used, 
 the lever will follow approximately the true pulse curve, 
 while if it is heavy it will fly up, making a sharp peak which 
 is very different from the true curve. 
 
 The sphygmograph was an advance over simply feeling 
 the pulse but it gave us an index of left ventricular contrac- 
 tion only. 
 
 Fig. 3. A diagrammatic representation of various forms of sphygmographic 
 tracings. The beginning of systole (1), and tlie dicrotic notch {3), the end of 
 systole are the only points of importance. The points {2) and {4) are variables 
 depending on the instrument used, conditions of blood pressure, etc., and may 
 be entirely disregarded. 
 
 THE POLYGRAPH 
 
 A great advance over the sphygmograph was made by 
 simultaneously recording the radial pulse, the venous pulse 
 in the neck, and the time, with an instrument called the 
 "polygraph. " This apparatus recorded the pulse in exactly 
 the same manner as the sphygmograph, while a second 
 similar recording device, placed over the right jugular vein, 
 recorded the pulse waves in this vessel. In a normal case 
 under good conditions, curves similar to those in figure 4 
 were obtained. The beginning of left ventricular systole 
 is shown in the radial pulse curve, and by a correspond- 
 ing wave c in the venous curve, the end of systole by the 
 
DEVELOPMENT OF KNOWLEDGE OF HEART RHYTHMS 17 
 
 dicrotic notch in the radial curve, and the downstroke 
 V in the venous cur\-e. One other wave (a) is seen in 
 the venous tracing, which occurs one-fifth of a second 
 before each ventricular systole. This was found to be due 
 to contraction of the auricles, so that with this instrument 
 
 Fig. 4. The upper curve is an actual polygraphic tracing. The lower one a 
 diagrammatic representation of one. It is seen that while the sphygmographic 
 tracing shows ventricular beats only, the venous tracing shows auricular as well 
 as ventricular beats. The points (a) showing auricular contraction, and the 
 points (c) and (v) showing the beginning and end of ventricular systole. 
 
 it is possible to record auricular as well as ventricular 
 beats. But difficulties were encountered which made this 
 apparatus less simple than it appeared to be. In some cases 
 where the patient moved or coughed, other waves appeared 
 in the venous curve as shown in figure 5 and in still other 
 
18 
 
 THE HEART RHYTHMS 
 
 cases as in figure 6 no auricular waves appeared at all. 
 It soon became evident that the venous pulse gave a very 
 uncertain curve. Taken by itself the curve has no charac- 
 teristic waves as the radial curve has. It is then of no 
 value alone but only when taken in relation to a curve in 
 which definite points are known, as the radial curve. It 
 is possible to plot the beginning and end of systole, definitely 
 
 Time /t " 
 
 Fig. 5. This curve is given to show that the interpretation of polygraphic 
 curves is not simple. Besides the auricular and ventricular waves other waves 
 may occur from movements of the patient or the instrument, and these can be 
 told from the auricular and ventricular waves only by careful plotting of known 
 points in the curve. 
 
 Fig. 6. In this polygraphic curve no auricular waves appear at all, in which case 
 one is not certain whether the auricle is beating or whether the curve is simply 
 badly taken. 
 
 shown in the radial curve, onto the venous curve, marking 
 where the beginning and end of systole come in this curve. 
 In this manner the waves which are of ventricular origin 
 are found, and we can look about for other waves which 
 might be caused by contraction of the auricles. In some 
 cases these waves are very clear, in others absent or obscure, 
 and though by careful study a great advance was made in 
 
DEVELOPMENT OF KNOWLEDGE OF HEART RHYTHMS 19 
 
 our knowledge of pathological rhythms by the use of this 
 instrument the whole subject was uncertain, and too difficult 
 for anyone but an expert. 
 
 THE ELECTROCARDIOGRAPH 
 
 The instruments of which we have thus far spoken re- 
 corded mechanically the pulse waves which follow heart 
 beats. In the electrocardiograph we have an instrument 
 of an entirely different character, which has nothing to do 
 with the actual contraction of the heart, but records the 
 impulses for these contractions. The principle is a simple 
 one although the instrument is of formidable appearance. 
 It is based on the fact that for a muscle to contract a stimu- 
 lus is necessary, and when this stimulus arises, whether it 
 be of nervous, mechanical, or chemical nature, an electrical 
 difiference of potential is set up in the muscle just before 
 its contraction. It is unnecessary here to go into the theory 
 of this electrical disturbance, the important point being 
 that it takes place a fraction of a second before, rather than 
 as the result of contraction, and we speak of it as an "im- 
 pulse" for contraction. Such a distrubance occurs when 
 any muscle contracts, and as the heart is a large muscle 
 it causes a relatively large disturbance. These changes of 
 potential can easily be recorded by placing the patient's 
 hands in jars of salt solution connected by wires to the elec- 
 trocardiograph. This is simply a very sensitive galvan- 
 ometer, or instrument for measuring small electrical changes 
 and an apparatus for recording them photographically. 
 The simplest form of galvanometer is one in which a coil 
 of wire is placed about a small compass. When there is 
 a flow of electricity through the coil, the needle of the com- 
 pass moves out of its normal position, and when the current 
 
20 THE HEART RHYTHMS 
 
 ceases the needle swings back again. All these simple 
 instruments need a relatively large current to affect them, 
 and the chief trouble comes from the inertia of the recording 
 device, for example the needle of the compass, which takes 
 some time to swing back to its original position, and so 
 is capable of recording only currents which occur at fairly 
 slow intervals. In the electrocardiograph an Einthoven 
 galvanometer is used, which is made on a different prin- 
 ciple from the compass galvanometer. Here the movable 
 part is a microscopic thread of quartz called a "string," 
 which is suspended vertically in a strong magnetic field. 
 When a minute current is passed through it, the "string" 
 is deflected, or really bent laterally. As the string is sup- 
 ported at both ends, has a very small mass, and moves 
 only a fraction of a millimeter, it has very little inertia, 
 and can record impulses up to many hundred times per min- 
 ute. These records are obtained by making the string 
 opaque with a coating of silver, placing it in a beam of light 
 which throws a vertical shadow, magnified by a microscope, 
 onto a metal plate in which there is a horizontal slot. This 
 slot allows only a point of shadow to pass through to a mov- 
 ing photographic plate or film, on which the point of shadow 
 writes in a continuous curve. The apparatus is shown 
 diagrammatically in figure 7. 
 
 When curves are taken of a normal individual with this 
 apparatus they are found to be of the following character 
 (fig. 8.) 
 
 Two distinct curves, or as we call them, "complexes" 
 are seen to occur at regular intervals. The first complex, 
 P, is a small upright curve. The second complex, QRST, 
 consists of a high vertical curve QRS, followed by a shght 
 depression, and then another lower and broader curve T. 
 Careful analysis shows that the first complex P is caused 
 
DE\'ELOP]VIENT OF KNOWLEDGE OF HEART RHYTHMS 21 
 
 by auricular contraction, and the second complicated curve 
 or ORST is of ventricular origin. The advantage of the 
 curves obtained with this instrument over those of the poly- 
 graph will be seen at once. In the polygraphic curves, 
 the radial tracing gives ventricular beats only, and the 
 venous cur\-e gives nothing characteristic, nothing which 
 
 Point of Shaaow. 
 
 Stnn, 
 
 '9- 
 
 .-Slot 
 
 L 3 
 
 Line of Shadow 
 
 Microscope 
 
 C 3 
 
 Lan 
 
 Conaenser. 
 
 'a Bath 
 
 Na^nQt. 
 
 '■■Film 
 Fig. 7. Diagrammatic representation of the electrocardiograph. 
 
 -Aj 
 
 .<? 5, 
 
 _2_L. 
 
 Fig. 8. A diagrammatic electrocardiogram of a normal rhythm. The auricular 
 impulse is shown by the upright curve P, and the ventricular imj^ulse by the 
 complicated curve or "complex" QRST, the beginning and end of wliich mark 
 the beginning and end of systole. 
 
 when the curve is taken separately can be identilied as 
 being of ventricular origin. It is only by analyzing the 
 venous tracing in relation to the known sphygmographic 
 curve that the origin of the waves in the venous curve 
 can be ascertained, and even these auricular waves are 
 determined by a process of exclusion. In the electrocar- 
 
22 
 
 THE HEART RHYTHMS 
 
 W ^ 
 
 
 
 w O 
 
 H a 
 
 
 8 < 
 
 u ft 
 
 W 
 
 Ah H 
 
 o 
 
 o a 
 
 
DEVELOPMENT OF KNOWLEDGE OF HEART RHYTHMS 23 
 
 diogram the auricular and ventricular complexes can be 
 picked out at once by their characteristic shapes, and when 
 the curves are well taken it is very simple to interpret 
 them, as for example that of figure 9, where it is e\'ident to 
 anyone that the auricle beats twice to each beat of the 
 ventricle. (Of course all curves are not as simple as this 
 diagrammatic one, as some auricular beats may fall in some 
 
 q s 
 J — - — ■ : 1 1 1 ' ' ' 1 1 — — —I 1 1 1 1 
 
 Fig. 9. A curve showing the simplicity of electrocardiograms compared with the 
 polygraphic tracings. Here it is verj^ evident that the auricle beats twice to each 
 beat of the ventricle. 
 
 part of the ventricular complex and be lost, but there are 
 ways of getting out of these difficulties which will be taken 
 up later.) 
 
 This short review of the instruments in use will make 
 it exident why it is simpler to begin our study of the heart 
 rhythms with electrocardiographic curves, rather than with 
 those of the supposedly simpler, because smaller, instru- 
 ments, the sphygmograph and the polygraph. 
 
CHAPTER II 
 
 Five Important Elements oe the Heart Beat 
 
 The clinician's training is so closely connected with heart 
 conditions of an entirely different nature from those dealt 
 with in this book that it is hard at first for him to disre- 
 gard his old ways of thinking, and to think of the heart 
 abstractly, and not as it actually appears with its valves, 
 its blood flow, etc. In the study of rh3^thms our interest 
 is in the time relation only of the contractions of the four 
 chambers of the heart and for our purposes the heart may be 
 represented by four circles as in figure 10 and everything 
 else disregarded. It will be found a great help if attention 
 is paid to this heart diagram as we develop it, and to think 
 of the time relation of beats of these circles to each other, 
 rather than of the auricles and ventricles themselves. 
 
 If now we expose an animal's heart to view under an anes- 
 thetic, five important points can be made out by simple 
 observation of the beating heart. These are 
 
 1. THE SIMULTANEOUS CONTRACTION OE BOTH AURICLES 
 AND BOTH VENTRICLES 
 
 In the first place it will be noticed that both auricles 
 contract simultaneously, and this contraction of both auri- 
 cles is followed after a short pause, by a contraction of both 
 ventricles. One never sees first one auricle contract, and 
 then the other, or the contraction of first one ventricle and 
 then the other, but the two auricles beat as one and the two 
 ventricles as one also. The two auricles are really one 
 large muscle whose cavity is divided by a thin septum, and 
 the same may be said of the ventricles, but the auricles are 
 
 24 
 
ELEMENTS OF THE HEART BEAT 
 
 25 
 
 distinctly separated from the ventricles by a band of tissue, 
 the auricular-ventricular septum. As both auricles beat 
 as one, and both ventricles beat simultaneously, we may 
 represent the heart as in figure 11, hereafter speaking of 
 it as having one auricle and one ventricle, and our problem 
 is reduced to the study of the time relation of contraction 
 
 Fig. 10 
 
 Fig. 11 
 
 Fig. 10. Diagrammatic representation of the four heart chambers, the time 
 relations of contraction of which we are dealing with in the study of the heart 
 rhythms. 
 
 Fig. 11. Reduction of the heart diagram to one auricle and one ventricle as 
 both auricles beat as one, and both ventricles as one also. 
 
 of these two chambers to each other. If there were no 
 factors governing the beating of these heart chambers, 
 the number of rhythms would be infinite, but fortunately 
 for us there are a few limiting factors which reduce the num- 
 ber of rhythms to a comparatively small number, and these 
 can all be observed in the beating heart. 
 
26 THE HEART RHYTHMS 
 
 2. THE RHYTHMICITY OE BEAT OE CARDIAC MUSCLE 
 
 The exposed heart will be seen to beat rhythmically and 
 regularly. When a strip of muscle is cut out of the heart 
 and suspended in the proper solution to nourish it, or if 
 the whole heart is removed and supplied by an artificial 
 circulation, the heart which was for a time quiet will begin 
 to beat, and this beat will occur at regular intervals. If 
 the rate is increased or decreased by various methods, 
 the rhythm will still be regular. 
 
 3. THE IMPULSE EOR CONTRACTION OCCURS AT THE POINT 
 OF GREATEST IRRITABILITY 
 
 It will also be noticed that the auricle beats first and is 
 followed by a ventricular beat, then there is a pause, and 
 another auricular beat occurs, followed again after a short 
 pause by a beat of the ventricle. One always speaks of 
 the ventricle following the auricle, but it is possible for this 
 order to be reversed. For instance if we cool the auricle 
 of a beating turtle's heart, without cooling the ventricle, the 
 auricle will beat more and more slowly, and finally the 
 ventricle will beat first, and be followed by an auricular 
 beat. That is, the auricle has been made relatively less 
 sensitive, or as we say "irritable," than the ventricle, so 
 much so that the ventricle contracts before the more slug- 
 gish auricle. And if we touch either the auricle or the 
 ventricle with a stimulating electrode, or any stimulating 
 substance, we may by increasing the irritant cause a con- 
 traction to occur before the normal time, while in patho- 
 logical cases conditions occur in which areas in the auricular 
 or ventricular muscle become abnormally irritable, and 
 premature beats arise from them. From these experiments 
 and others which will be taken up later, it appears that the 
 
ELEMENTS OF THE HEART BEAT 27 
 
 beat arises from the point of greatest irritability in the 
 heart, that normally the auricle becomes more irritable 
 than the ventricle, and consequently beats first, but that 
 artificially the ventricle can be made more irritable than 
 the auricle, in which case the beat will arise in the ventricle. 
 Also that the beat may occur out of time in either the auri- 
 cle or ventricle, if these chambers are irritated by some 
 means. 
 
 4. THE REFR-ACTORY PERIOD OF THE VENTRICLES 
 
 We have seen that when the beating heart is touched by 
 a stimulating electrode, a contraction of the chamber stimu- 
 lated takes place at once. This is true of the auricle, but 
 if one repeatedly touches the ventricle with such an elec- 
 trode, it will be found that there are periods in which 
 the ventricle will not respond to stimulation. These periods 
 occur during a ventricular contraction and shortly after. 
 It seems as if the ventricle were like a gun, taking a certain 
 length of time to reload and while reloading cannot be 
 fired. The auricle on the other hand loads so quickly 
 that one cannot get ahead of it, and it will fire as fast as the 
 trigger is pulled. This period in which the ventricle will 
 not respond to stimulation is called the "refractory period," 
 and is of importance because in abnormal cases in which 
 the auricle is beating very rapidly some of the auricular 
 impulses reach the ventricle when it is in this refractory 
 state, and no ventricular contraction will take place. 
 
 5. THE CONDUCTION OF IMPULSES FROM AURICLE TO 
 VENTRICLE 
 
 We have noticed in the beating heart that the auricular 
 beat is followed after a short pause by a beat of the ventri- 
 cle. This pause is normally about one-fifth of a second. 
 
28 THE HEART RHYTHMS 
 
 It is due to the time taken for the auricular impulse to pass 
 from the auricle to the ventricle. That such an impulse 
 is transmitted from one of these heart chambers to the other 
 can be easily shown in the turtle's or frog's heart by means 
 of a specially devised screw clamp. This is so made that 
 any desired pressure may be brought to bear on the septum 
 connecting the auricles with the ventricles. If only slight 
 pressure is exerted, the time taken for passage of the auric- 
 
 hurlcutar- MdntrLculat 
 Bundle. 
 
 Fig. 12. The addition of the auricular-ventricular bundle to the heart diagram, 
 in order to deal with the conduction of impulses from auricle to ventricle. 
 
 ular impulse from auricle to ventricle is increased from 
 one-fifth of a second to two- or three-fifths or more. Even- 
 tually the time taken for the passage of one impulse be- 
 comes so great that the auricle may beat twice or even three 
 or four times to one beat of the ventricle, and finally, if 
 the clamp is completely closed, shutting off the auricles 
 from the ventricles entirely, these two chambers beat ab- 
 solutely independently of each other. It has been found 
 
ELEMENTS OF THE HEART BEAT 29 
 
 that these impulses are transmitted through a band of 
 speciaHzed muscle tissue, running from auricle to ventricle, 
 and called the "auricular ventricular bundle" or "bundle of 
 His." In the hiunan heart this bundle is easily seen with the 
 naked eye. \Vhen this bundle is cut, no impulses pass 
 from auricle to ventricle, and in man cases are observed 
 in which the ventricles beat independently of the auricles 
 and autopsy shows a gumma or arteriosclerotic changes 
 which have destro3^ed the bundle. This conduction bundle 
 is then of importance to us in the study of heart rhythms 
 and we must add it to our heart diagram (figure 12). 
 
 SUMMARY 
 
 From simple observation we have learned that the heart 
 beats at regular intervals. That the beat arises at the 
 point of greatest irritability. That as the auricle normally 
 beats first, it may be supposed to be more irritable than 
 the ventricle, but that this condition may be experimentally 
 or pathologically changed, and the auricle or ventricle, 
 made more irritable by some agent, will beat out of time. 
 That the auricle recovers quickly from a beat, and is always 
 ready for the next one, but that the ventricle is relatively 
 sluggish, and cannot be made to beat again until a certain 
 amount of time has elapsed, which time we call the 
 "refractory period. " That impulses for ventricular contrac- 
 tion arise in the auricle, and are transmitted to the ventri- 
 cle by means of the auricular ventricular bundle. That 
 when this bundle is impaired by any means a greater length 
 of time is needed for the passage of auricular impulses, and 
 when the bundle is destroyed no impulses pass from auri- 
 cle to ventricle, and each beats quite independently of the 
 other. 
 
CHAPTER III 
 
 The Division of the Heart Into Functional Areas by 
 Means or the Electrocardiograph 
 
 By simple observation we have been able to make out 
 the chief factors which control the heart rhythm, but we 
 have a far better method of studying these in the electro- 
 cardiograph. If we anesthetize an animal which is suitably 
 connected with this instrument, and expose the heart to 
 view, the electrical disturbance set up by the beating heart 
 will be recorded in a curve similar to that of figure (13). 
 We have already said that the complexes P are caused 
 by auricular impulses and the complexes QRST by 
 impulses for ventricular contraction, but no mention was 
 made of how this was known. In the first place when an 
 electrocardiogram is taken, and recorded on the same plate 
 as curves made mechanically by levers attached to the 
 auricle and ventricle, it will be found that the P waves 
 occur an instant before the mechanical auricular waves, 
 and that the complexes QRST also occur a moment before 
 the mechanical contraction of the ventricle, from which 
 we may conclude that the P wave represents the auricular, 
 and the complex QRST the ventricular impulse. When 
 very careful measurements are made it is found that the 
 curves recorded in the electrocardiogram always preceded 
 by an instant the corresponding beat of the heart. Although 
 we do not know just what the electrical phenomenon is, 
 which goes on at this time, it seems that the difference 
 of potential is not caused by muscular contraction, as 
 it is recorded just before contraction takes place. Also 
 in an excised heart which has ceased to beat, very good 
 
 30 
 
DmSION INTO FUNCTIONAL AREAS 
 
 31 
 
 electrocardiograms may be recorded. We believe then 
 that the electrocardiograph records impulses for contraction 
 and not a disturhauce set iip by contraction. This is im- 
 portant, because the size and shape of the curve is in no 
 way dependent upon the size and force of the beat. A good 
 
 'II ^ ' 1 1 — 1^ ^ ' 
 
 utfA'i ■HWMI^tf 
 
 -Aj 
 
 . <? s . 
 
 Fig. 13. The upper figure gives normal electrocardiograms from a human 
 subject, showing the so called three "leads" described on page (60). This is done 
 by placing the electrodes on different parts of the body, which emphasizes differ- 
 ent portions of the curve as seen in these three electrocardiograms of the same 
 subject. The lower curve gives a diagrammatic one which will be used entirely 
 throughout this book for the sake of simplicity. Lower curve same as figure 8. 
 
 example of this is that of premature beats of the ventricle 
 which give such a small pulse wave that they are often not 
 felt at the wrist, and are spoken of as skipped beats. The 
 electrocardiogram gives an abnormally large comi)lex for 
 these small beats, and a normal complex for the large j)ulse 
 wave which follows these. This relationship can be seen 
 in figure 14. Although the size of the electrocardiographic 
 
32 
 
 THE HEART RHYTHMS 
 
 complex is of no importance to us as an index of the size 
 of the beat, the shape of the complex is of the greatest 
 importance, because by it we are able to locate the origin 
 of the impulse, whether in the auricle or the ventricle, and 
 whether it arises in a normal or abnormal position in these 
 heart chambers. That the shape of the electrocardiographic 
 impulse is characteristic of the point of origin of the impulse 
 
 Time, 'js 
 
 Fig. 14. The upper curve gives an electrocardiogram of an ectopic ventricular 
 beat, the complex of which is much larger than that accompanying a normal 
 beat, while the radial pulse shows a small pulse wave for the ectopic beat. 
 The curve is given to show that the size of the wave in the electrocardiogram is 
 in no way proportional to the actual size of the heart beat. 
 
 was discovered by stimulating the exposed heart in many 
 places with single induction shocks, which caused the 
 auricle or ventricle to contract, and recording the impulses 
 for these contractions with the electrocardiograph. In 
 this way the heart was functionally mapped out into the 
 following areas. 
 
 1. The sino- auricular node. A small node of specialized 
 muscle tissue located at the junction of the great veins of 
 the neck with the auricles. 
 
 2. The auricular-ventricular node and bundle. Situated 
 at the base of the auricle at the beginning of, and really a 
 
DIVISION INTO FUNCTIONAL AREAS 33 
 
 part of, the auricular-ventricular bundle. This is also 
 made of the same tissue, and runs from the auricular-ven- 
 tricular node to the ventricle, where it divides into two 
 branches, one going to each ventricle. 
 
 3. The auricular musculature. That is, the mass of 
 cardiac muscle making up the auricle, and which we cannot 
 differentiate into any particular areas. 
 
 4. The ventricular musculature. WTiich is the general 
 musculature of the ventricle. 
 
 Beats may arise from any of these four areas, and each 
 beat will give its characteristic complex and thus be located 
 at once. These areas and their characteristic complexes 
 are shown in figure 15. It will be seen that the only differ- 
 ence in the impulses arising at the sino-auricular node, 
 and those from the general musculature of the auricle 
 is that one gives upright complexes, while the others are 
 inverted. If we consult the electrocardiogram of a normal 
 heart (fig 13) it will be seen that the auricular impulse 
 normally arises at the sino-auricular node, and the normal 
 ventricular impulse at the auricular-ventricular node. If 
 for any reason an impulse arises outside these normal areas, 
 we speak of it as an "ectopic" impulse of auricular or 
 ventricular origin. 
 
 The ectopic ventricular complexes are not always of a 
 very distinguishing shape, but, when one takes an electro- 
 cardiogram in which normal ventricular complexes are 
 present, it is usually simple to differentiate an ectopic 
 complex from a normal one. As a rule they are higher and 
 broader, and the T wave may be inverted. On the other 
 hand impulses may arise in one of the branches of the auric- 
 ular-ventricular bundle which are very hard to tell from 
 the normal. But these are minor details and will be taken 
 up later; the point of interest here is that in the electrocardio- 
 
34 
 
 THE HEART RHYTHMS 
 
 graph we have an instrument with which we can record 
 the time relation of contraction of the auricle to the ventricle 
 with great accuracy, and with which it is possible to tell 
 whether the impulse for contraction arises at the normal or 
 
 wm \mi« 
 
 Mantrick 
 
 Fig. 15. Diagram showing the division of the heart into four functional areas 
 by means of the electrocardiograph, and giving the characteristic complexes for 
 each of these four areas. 
 
 at an abnormal place or "focus." It is also interesting to 
 note that it has been possible to differentiate these areas 
 in the heart functionally as well as anatomically. This 
 instrument gives then a method by which we can make a 
 complete study of the heart rhythms, and allows us to 
 classify them on the basis of point of origin of impulses. 
 
CKL\PTER IV 
 
 The Classefication of Cardlic Rhythms on the Basis 
 OF Point of Origin of Impulses 
 
 As we are able to differentiate the heart into four areas 
 only, from which impulses may arise, we can have only 
 four classes of cardiac rhythms based on the point of origin 
 of impulses. These four classes are as follows: (1) Sino- 
 auricular rhythms, (2) ectopic auricular rhythms, (3) auricular- 
 ventricular nodal rhythms, (4) ectopic ventricular rhythms. 
 
 Let us take up each of these rhythms from a theoretical 
 point of \dew, calculating from our knowledge of certain 
 functions of cardiac muscle which we have already taken 
 up, and our knowledge of the normal electrocardiogram, 
 what rhythms are likely to occur when impulses arise in 
 these four different heart areas. 
 
 I . siNO- auricular rhythms 
 
 By simple observation of the beating heart we found that 
 the two auricles beat as one, and the two ventricles as one 
 also, and that we could consider the heart for our purposes 
 as consisting of one auricle and one ventricle. We saw 
 that the auricle beat first, and the ventricle one-fifth of a 
 second later. We concluded that the ventricular contrac- 
 tion was dependent upon impulses received from the 
 auricle by way of the auricular-ventricular bundle because 
 if this bundle were injured the ventricle would wait for the 
 delayed auricular impulse. And if the bundle were 
 destroyed no further relationship between the auricles and 
 ventricles could be made out. When we took an 
 
 35 
 
36 THE HEART RHYTHMS 
 
 electrocardiogram of such a heart, we found that the 
 auricular complexes were characteristic of impulses arising 
 from the sino-auricular node, and the ventricular im- 
 pulses characteristic of others arising from the auricular- 
 ventricular node started by impulse waves coming from the 
 auricle. Why these impulses arise we do not know, but 
 we do know that the rate at which they arise varies from 
 time to time, that we can influence this rate by various 
 means, and that the rate is under nervous control. This 
 is shown by the fact that stimulation of the accelerator 
 nerve causes an increase in rate, while stimulation of the 
 vagus nerve causes a decrease in the heart rate. Certain 
 chemicals, as calcium, will increase the rate and others, as 
 potassium, will decrease it. And then there are compli- 
 cated factors which influence the heart rate that cannot 
 be so easily analyzed, as for instance the changes in exercise, 
 the increased flow of blood, the increase in respiratory 
 rate, the various chemical changes in the blood, etc., all 
 of these things are liable to vary the heart rate and although 
 we do not know just what occurs in the sino-auricular node 
 at the time of impulse formation, the important points to 
 be noted are that the impulses arise at regular intervals, 
 no matter what variation in rate occurs, and any variation 
 in rate of rhythms arising at the sino-auricular node is a 
 gradual variation. There is never any sudden break in 
 the rhythms as that which occurs in other conditions. 
 
 We have four uncomplicated sino-auricular rhythms 
 which are: 
 
 1. The normal heart beat 
 
 a. Simple tachycardia. That is, a normal but fast 
 rhythm. 
 
 b. Simple bradycardia. A normal but slow rhythm. 
 
CLASSIFICATION OF CARDLA.C RHYTHMS 37 
 
 c. Sinus arrhythmia. This term is applied to gradual 
 variations in rate as those occurring -with exercise, etc., 
 but chiefly to the variation in rate which comes mth each 
 respiration. This may be quite marked in some nervous 
 young people, and is always very marked in children. 
 It is an entirely normal condition and simply shoM^s an 
 active respiratory center. 
 
 We have seen that an electrical or chemical stimulus 
 applied to the auricle or the ventricle would cause these 
 chambers of the heart to contract. It is thus easy for us to 
 conceive of some point in either the auricle or the ventricle 
 becoming stimulated in the human heart by some patho- 
 logical condition. Such conditions do occur as in posioning 
 by chemicals, from changes brought about by infections, 
 and cellular changes in the cardiac musculature. They 
 give rise to beats which are recognized by their characteris- 
 tic complexes in the electrocardiogram as being of ectopic 
 origin. As normally the impulse for a cardiac cycle arises 
 at the sino-auricular node, we may have ectopic impulses 
 from any of the other three areas of the heart, that is, from 
 the auricle, the auricular-ventricular node and bundle, 
 and from the musculature of the ventricle, and clinically 
 all such abnormalities of rhythm occur. Let us take up 
 each of these three types of rhythm separately, beginning 
 with 
 
 2. Ectopic heats interrupting the normal heart beat 
 
 a. Ectopic auricular heats. We have observed that one 
 of the functions of cardiac muscle is the rhythmicity of 
 beat. If a normal rhythm is interrupted by an ectopic 
 auricular beat which will be followed in the normal time by 
 a normal ventricular beat, it will interrupt that one cardiac 
 cycle, but the auricle will begin to beat again normally 
 
38 THE HEART RHYTHMS 
 
 at once, because if a second ectopic impulse does not occur, 
 an impulse will arise from the sino-auricular node and the 
 heart will go on beating normally. The extopic beat must 
 occur prematurely or otherwise it will be time for a normal 
 sino-auricular impulse. That is why these are often called 
 "premature" beats, but the term "extra systole" is wrong 
 as there is no extra beat, merely a premature one. 
 
 If we examine the electrocardiogram of such a case, we 
 find a curve similar to that in figure 16. The regularly 
 occurring P waves followed in the normal time by normal 
 ventricular complexes are interrupted at X by an auricular 
 complex occurring prematurely. It will be noted that the 
 complex is inverted, which at once tells us that the impulse 
 
 p 
 
 p 
 
 Time. 'Is' 
 
 Fig. 16. Curve of an ectopic auricular beat, showing the inverted auricular 
 complex, and the beat arising prematurely. It is followed by a normal ventricular 
 beat in the usual conduction time. 
 
 arose from an ectopic focus in the auricle, and it will also 
 be noticed that this ectopic auricular wave is followed by 
 a normal ventricular complex. The reason for this is of 
 course evident, because auricular impulses, no matter of what 
 origin, can reach the ventricle by way of the auricular-ventric- 
 ular bundle only, and in so doing must set up a normal im- 
 pulse for ventricular contraction. The conduction time from 
 auricle to ventricle will be normal as there is no abnormality 
 of the conduction bundle. Following the ectopic beat, the 
 heart goes back to its normal rhythm. The next auricu- 
 lar impulse is seen to be of sino-auricular origin and may 
 occur at the normal time after the ectopic beat, sooner 
 or later than normal, depending entirety upon the state of 
 
CLASSIFICATION OF CARDIAC RHYTHMS 39 
 
 the sino-auricular node. Attention is called to this point 
 in contradistinction to ectopic ventricular beats, which 
 are always followed by a pause of the ventricle of a definite 
 length. This pause is due to the ventricle waiting for the 
 next auricular impulse, and is of importance in polygraphic 
 tracings as a means of distinguishing between auricular and 
 ventricular ectopic beats, but it has no significance here 
 in electrocardiograms because the shape of the complex 
 tells us at once whether we are dealing with an auricular 
 or a ventricular beat. 
 
 Time 'js- 
 
 FiG. 17. Curves of a premature beat arising at the auricular- ventricular node. 
 It will be noticed that the electrocardiogram shows simply an absence of an auric- 
 ular impulse. The polygraphic curve on the other hand shows a small arterial 
 pulse wave at the time of the premature beat, but an abnormally high c or 
 arterial wave in the venous curve at this time, which leads one to believe that 
 the auricle and ventricle contract simultaneously. 
 
 h. Ectopic auricular -ventricular nodal heats. In the 
 same way an ectopic beat may arise from the auricular- 
 ventricular node, and interrupt the normal rhythm. It 
 is recognized by a normal ventricular complex occurring 
 prematurely, and the absence of an auricular complex. 
 This is due to the impulse arising at a point about equidis- 
 tant from the auricle and the ventricle and being trans- 
 mitted to each of these heart chambers in the same length 
 of time and thus stimulating them to contract at once. 
 
40 
 
 THE HEART KEYTHMS 
 
 Such a beat is shown in fig. 17. There is no proof from 
 such an electrocardiographic curve that the auricle does 
 beat, but if one takes a simultaneous tracing with the 
 polygraph it will be seen that the ventricular curve for the 
 premature auricular-ventricular nodal beat, in the radial 
 tracing, is if anything smaller than normal, while the cor- 
 responding ventricular curve in the venous tracing is much 
 larger than normal. As no auricular wave is seen, it is 
 supposed that the reason for this abnormally large ventric- 
 ular wave in the venous curve is the simultaneous contrac- 
 
 Timd 'Is". 
 
 Fig. 18. Same as figure 14. Premature ventricular beat. 
 
 tion of the auricle and the ventricle sending a large wave 
 up the vein. 
 
 c. Ectopic ventricular beats. Similarly the normal rhythm 
 may be interrupted by an ectopic beat of ventricular origin. 
 This is recognized at once by a premature ectopic ventricular 
 complex occurring in the curve, as shown in figure 18. 
 It gives a curve which is of interest because it shows that 
 the auricle is not upset in its rhythm by the abnormal ven- 
 tricular beat, but continues beating regularly in its usual 
 manner. The ectopic beat occurred prematurely and when 
 the next beat came down the auricular- ventricular bundle 
 it found the ventricle in the " refractory " 'state (see p. 27) 
 
CLASSIFICATION OF C-ARDLA.C RHYTHMS 41 
 
 in which it could not respond to stimulation. The ventri- 
 cle thus did not contract, and paused until the next auricular 
 impulse arrived. Considerable emphasis is laid on this 
 pause in polygraphic curves as it gi^'es a method of distin- 
 guishing auricular from ventricular ectopic beats. It is 
 however of no significance in our study here, but it is in- 
 teresting to note that there really is no pause in the ventric- 
 ular rhythm, but that every beat is on time except the 
 ectopic beat which occurs prematurely. 
 
 These ectopic beats of auricular, auricular-ventricular 
 nodal, or ventricular origin, may occur singly at rare intervals, 
 or frequently, giving a regular pulse broken occasionally 
 by a single beat, or a pulse which is so irregular that it is 
 impossible to distinguish it from the absolute irregularity of 
 auricular fibrillation. 
 
 n. ECTOPIC AURICULAR RHYTHMS 
 
 We have seen that it is possible for some ectopic focus in 
 the auricle to become irritated, and for a single ectopic beat 
 to arise from this focus. It is also possible for this irrita- 
 tion to become so constant that all the auricular beats 
 arise from this point and none from the sino-auricular node, 
 in which case we have a condition of an ectopic auricular 
 rhythm. An electrocardiogram of such a rhythm is shown 
 in figure 19. 
 
 During the establishment of the ectopic rhythm one may 
 see runs of ectopic beats, then a return to the normal, 
 then ectopic beats, etc., but when the ectopic rhythm is 
 once established no sino-auricular impulses can be made 
 out until the rhythm suddenly stops and returns to normal, 
 when all of the auricular complexes are again of the sino- 
 auricular type. 
 
42 THE HEART RHYTHMS 
 
 Auricular impulses of ectopic origin, as shown by the 
 inverted complexes, arise at regular intervals and are fol- 
 lowed in the normal time by normal ventricular complexes. 
 Although all ectopic auricular rhythms are fundamentally 
 of this same type, they fall into quite sharply defined 
 clinical groups for two chief reasons: these are, the rate 
 at which they occur, and the mechanical effect on the cir- 
 culation. The first of these groups is that of 
 
 1. Paroxysmal tachycardia 
 
 In certain cases we find patients with the heart beating 
 regularly and at the normal rate when suddenly they are 
 conscious of a very fast throbbing circulation. They 
 
 T/me '/s 
 
 Fig. 19. Curve of an ectopic auricular rhythm in which all the auricular com- 
 plexes are of the inverted type and followed in the normal time by normal ventricu- 
 lar complexes. 
 
 become nervous, frightened, short of breath, are conscious 
 of palpitation, and the veins of the neck are usually swollen. 
 The pulse is found to have increased enormously in rate, 
 being often twice what it was before. It is regular and an 
 electrocardiogram shows a regular rhythm in which all the 
 auricular impulses are of ectopic origin, and each auricular 
 beat is followed by a normal ventricular complex. Such 
 a curve is shown in figure 19. 
 
 The attack may last for five or ten beats, several minutes, 
 or many hours, and leave as suddenly as it came on. The 
 cause of this condition is unknown, and nothing has been 
 found which will shorten an attack although many sub- 
 stances are believed to, but the electrocardiogram shows 
 
CLASSIFICATION OF C-Aja)L4C RHYTHMS 43 
 
 US definitely that the patholog>- of the condition is the 
 ectopic origin of all auricular impulses. There are several 
 points of interest here. In the first place it will be noticed 
 that the rate is much above the normal, roughly 180 to 
 220 per minute. A possible reason for this is that if impulses 
 arose from this ectopic focus at a slower rate than that of 
 the normal heart, the sino-auricular node would break 
 in and reestabhsh itself. Very often cases are found in 
 which this occurs. There mil be a run of three or four 
 ectopic beats and then a few normal ones, then a short run 
 of ectopic beats and finally the ectopic rhythm will be estab- 
 hshed with all the impulses of ectopic origin. There is 
 howe^•er no gradual variation in rate. An ectopic rhythm 
 assumes a rate of its oa\ti, and beats with great constancy, 
 perhaps because it is not under any nervous control. The 
 actual rate at which these impulses arise has a marked 
 clinical significance. The ventricle is able to follow the 
 auricle up to rates of about 220 per minute, and these cases 
 in which each auricular beat is followed by a ventricular 
 one are classified as paroxysmal tachycardia, the name, 
 paroxysms of rapid heart beat, being well suited to the 
 condition. With such a rapid ventricular rate there is 
 necessarily a considerable circulatory disturbance of which 
 the patient is aware. \\Tien however the auricular rate 
 goes above 220 or thereabouts, the ventricle is unable to 
 follow the auricle and we have an entirely different clinical 
 picture, which has been given the name of 
 
 2. Auricular flutter 
 
 The patholog>' of this condition is exactly similar to that 
 of paroxysmal tachycardia, namely, an ectopic auricular 
 rhythm, but when the auricle is beating at a rate of 220 to 
 
44 THE HEART RHYTHMS 
 
 450 per minute the ventricle can no longer follow it, and 
 we have two or three auricular beats to one of the ven- 
 tricle. In such a case although the auricular rate is very 
 great, the ventricular rate may be about normal, one 
 hundred or so, and if the ventricle happens to follow an 
 even number of auricular beats, the pulse may be perfectly 
 regular. As the ventricle is pumping about the normal 
 amount of blood through the body, there is none of the 
 circulatory disturbance which is seen in paroxysmal tachy- 
 cardia, and the patient complains only of a curious sensa- 
 
 Timi'/s 
 
 Fig. 20. Curve of auricular flatter in which the ventricular rhythm is irregular 
 on account of the ventricle following an irregular number of auricular beats. 
 
 Fig. 21. Another curve of auricular flutter in which the ventricle follows every 
 fourth beat of the auricle and gives a regular ventricular rhythm. 
 
 tion of "fluttering" about the heart, and a sense of weak- 
 ness. These cases are often missed on account of the slow 
 and regular pulse. When however an electrocardiogram 
 is taken, the condition is seen at once. Figure 20 gives a 
 diagrammatic curve of such a case. Here we have ectopic 
 auricular complexes occurring at a very rapid and regular 
 rate, and sometimes two, three, or four auricular beats 
 followed by a beat of the ventricle. In figure 21 we have 
 the same condition, in which however the ventricle follows 
 every fourth auricular beat and gives a slow and regular 
 pulse. 
 
CLASSIFICATION OF CARDIAC RHYTHMS 45 
 
 3. Auricular fibrillation 
 
 If the auricular rate goes above 450 or thereabouts, it 
 is impossible for the auricle to contract coordinately, and 
 it goes into a state of so called "fibrillation." This con- 
 dition is often seen in laboratory work when one tries to 
 perfuse a heart through the coronary arteries. The auricle 
 may beat a few times and then it fills passively with blood 
 and twitches in many minute contractions in different 
 parts of its surface at once, but there is no coordinate 
 
 wv^ 
 
 .-J \/y^\^iy^\.,'-.-J\^^ 
 
 r.a,^/, 
 
 Fig. 22. Three curves of auricular fibrillation. It will be seen that in all of 
 them the ventricle beats absolutely irregularly. There are no distinct auricular 
 complexes seen, but in curve 1 rapid nearly regular oscillations of the curve 
 can be made out. In curve 2 fewer and more irregular oscillations are seen 
 while in curve 3 the curve is practically a straight line between ventricular 
 beats. 
 
 contraction of the whole auricle. If one looks at it care- 
 fully it will be seen that innumerable contractions are taking 
 place in small groups of muscle fibers. When an electro- 
 cardiogram is taken of such a case it is found that the impulses 
 are arising from ectopic foci in the auricle at a very great 
 rate, 500 per minute and faster. These may occur regularly 
 as minute auricular complexes, or irregularly, and in old 
 cases which have fibrillated for some time no definite 
 auricular impulses can be made out. Curves of all three 
 such conditions are shown in figure 22. It seems best 
 
46 THE HEART KEIYTHMS 
 
 not to be too certain in trying to decide just which is a 
 case of flutter, and which is fibrillation. If auricular 
 complexes occur at regular intervals, and polygraphic 
 tracings show regular auricular waves, it is probable that 
 the auricle is really beating, and we are dealing with a 
 case of flutter. If however, we happen to find regular 
 complexes at a rate of 600 per minute, and no well marked 
 auricular waves in the polygraphic tracings it is probable 
 that the auricle is not contracting coordinately. In all 
 cases of fibrillation the auricular impulses are arising at 
 such a very rapid rate that it is impossible for the ventricle 
 to follow and it beats in an absolutely irregular manner. 
 The irregularity is so marked and so persistent that these 
 cases have been recognized for many years before any means 
 of taking tracings were found. 
 
 Our knowledge of impulse formation still is very incomplete but 
 more is being rapidly found out. The normal auricular impulse 
 apparendy arises at the sino auricular node and spreads in a wave 
 over the auricle in all directions reaching the auricular ventricular 
 node and starting there another impulse for ventricular contraction. 
 When an ectopic auricular impulse arises the impulse spreads from 
 this point in waves to all parts of the auricle, and again reaches the 
 auricular-ventricular node and sets up a ventricular impulse. If 
 however we have an ectopic auricular rhythm as for instance paroxys- 
 mal tachycardia once established it is interesting that the sino- 
 auricular node which may be supposed to be quite normal, does 
 not break in on the ectopic auricular rhythm and interrupt it. 
 In seeking for some explanation for this one might imagine, 
 with no proof of it, that the ectopic impulse wave travelling over 
 the auricle reaches the sino-auricular node and discharges the impulse 
 which is building up there before it has become of sufficient magni- 
 tude to discharge of its own accord and break in on the ectopic 
 rhythm. When for any reason the ectopic rhythm fails for a beat, 
 the sino-auricular node is then ready to discharge and again assumes 
 command of the rhythm. 
 
CLASSIFICATION OF C.ARDLA.C RHYTHMS 47 
 
 In auricular flutter, it is now believed that the cause of the very- 
 rapid (roughly 450 per minute) rate of auricular contractions is 
 not due to impulses arising at some one ectopic focus in the auricle 
 but that there are so called "circus contractions" taking place in 
 the auricle. It was found some years ago in certain types of medusa, 
 or contracting "jelly fish" that strips cut from them would show 
 a wave of contraction starting at one end and passing off at the other. 
 That after the passage of a contraction wave this point would become 
 refractive and refuse to respond to stimuli for some little time. By 
 cutting out a circular piece or ring strip of tissue it was possible 
 to start a wave travelling around the ring. If the ring were of suffi- 
 cient length when the wave of contraction had made a complete circle 
 and reached the starting point again the refractory stage had passed 
 off and the strip w^as ready to contract once more. In this way it 
 was possible to keep up a wave of contraction travelling around the 
 ring for days. This same phenomenon has been observed in strips cut 
 from the hearts of the dog fish, the turtle, and the dog, and lately it 
 has been experimentally shown in flutter produced in dogs that 
 there is such a wave of contraction travelling around a ring at the 
 junction of the great veins with the auricle. Such a wave in its rapid 
 circular movement sends off waves of impulses over the auricle which 
 cause it to beat, and stimulate in turn the auricular ventricular node. 
 As long as this vicious circle of impulse around the veins occurs 
 the flutter continues, but if a change in the conduction of this 
 strip of tissue can be brought about which will break up the ring wave 
 of contraction the sino-auricular node will then have a chance to send 
 out its impulses to the auricle, and the normal rhythm will be again 
 established. Such treatment has already been successful in certain 
 cases but does not lie within the scope of this book. 
 
 In auricular fibrillation it is still undetermined whether the enor- 
 mous number of impulses which are shown in the electrocardiogram 
 arise from muhiple foci of stimulation or whether they are complicated 
 irregular "circus movements" similar to those of auricular flutter. 
 For our purpose of studying the heart rhythms however this may be 
 disregarded, and three types of auricular ectopic rhythms considered, 
 simply from the different clinical pictures which they present. In 
 the first, paroxysmal tachycardia, the ventricle follows each beat of 
 the auricle, and gives a picture of a rapid circulation, in flutter the 
 
48 THE HEART RHYTHMS 
 
 ventricle cannot follow the fast auricular rate and the pulse may be 
 of about normal rate and the circulation apparently normal, while 
 in fibrillation the auricular rate is too great for coordinated auricular 
 contractions. Although all types are simply due to ectopic auricular 
 impulses they cause quite different clinical pictures, whichjustifi.es 
 this classification. 
 
 m. AURICULAR VENTRICULAR NODAL RHYTHMS 
 
 In exactly the same way that a point in the auricle may 
 become irritated and give rise to an ectopic auricular 
 
 ■J u/'>«i^ L/>iii»J l../^.iii.iJ L/NmmJ 
 
 Fig. 23. Curve of an auricular-ventricular nodal rhythm. In this condition, 
 which is very rare, the impulse for contraction arises in the auricular-ventricular 
 node, and the auricles and ventricles contract simultaneously. No auricular 
 complexes are visible. 
 
 Fig. 24. Curve of a rare case of ectopic- ventricular rhythm in which the ventric- 
 ular beats are of ectopic origin, and a fairly normal rate, and the ventricle is 
 beating entirely independently of the auricle. 
 
 rhythm, the auricular-ventricular node may become the 
 point of greatest irritability, and a rhythm may be set up 
 in which all impulses originate from this node. As shown 
 in figure 23, the rhythm will be regular, on account of 
 the tendency of cardiac muscle to beat regularly, and the 
 rate will be very limited. In fact it is a very rare condition 
 and the reason for this will be seen if we think of just what 
 the rhythm means. When an impulse arises at the auricu- 
 lar ventricular node, the auricle and ventricle both beat at 
 once. If the rate is fast the ventricle must follow each 
 
CLASSIFICATION OF CARDIAC RHYTHMS 49 
 
 impulse, it vdW not have time to fill properly with blood, 
 and the circulation wdll not be properly maintained. If 
 the rate is very slow, the sino-auricular node will break in 
 and start the normal rhythm again. Thus there is a 
 comparatively narrow range of rates in which it would be 
 possible for such a rhythm to be established. As has been 
 said, the condition is extremely rare. 
 
 IV. ECTOPIC-VENTRICULAR RHYTHMS 
 
 In the same way that a point in the auricle may become 
 irritated and give rise to an ectopic auricular rhythm, it 
 is conceivable that a point in the ventricle might also be- 
 come irritated and give rise to an ectopic ventricular rhythm. 
 But such a rhythm would have to be rapid or else the sino- 
 auricular node would break in and upset the rhythm. We 
 see many instances of this in which there are runs of ectopic 
 ventricular beats, and then a return of the normal rhythm. 
 If the runs are of fairly long duration they are very upset- 
 ting to the patient, as the rapidly beating ventricle cannot 
 pump sufficient blood to maintain the circulation. Certain 
 very rare cases of temporary ventricular paroxysmal tachy- 
 cardia, flutter and fibrillation have been reported, which 
 are of theoretical interest as it shows us that all the possible 
 rhythms which we can calculate from our classification of 
 rhythms do occur, but for all practical purposes we may 
 say that ectopic-ventricular rhythms are incompatible with 
 life. The one case of ventricular fibrillation which I have 
 seen reported was one in which an electrocardiogram was 
 being taken from a patient with a very bad heart. Suddenly 
 the patient became pulseless, stopped breathing and was 
 considered dead. The electrodes were removed, when 
 suddenly the patient began to breathe, recovered and lived 
 for twenty hours longer. On development of the film it 
 
50 THE HEART RHYTHMS 
 
 was found that during the time of unconsciousness the 
 ventricle went into a state of fibrillation, but was unable 
 to maintain the circulation and the patient became uncon- 
 scious and pulseless. It is probable that the establishment 
 of an ectopic-ventricular rhythm is often the cause of sudden 
 death. 
 
 It has been shown that we have rhythms arising from each 
 of the four heart areas. We have shown that each of these 
 rhythms could be broken in on by impulse^ from any of the 
 other areas. We have pointed out that there is a hmit to 
 the rate at which the ventricle can contract and still main- 
 tain an efficient circulation, and that even the auricle can 
 not contract coordinately above a certain rate. We have 
 considered all rhythms arising from the four areas into 
 which we have divided the heart, and seen that their number 
 is Hmited by certain functions of cardiac muscle. 
 
 Theoretically it is possible for impulses to arise from 
 all four areas at once, from points near the auricular ven- 
 tricular bundle giving curves slightly differing from nodal 
 rhythms, etc. These are of interest theoretically, but are 
 so extremely rare that they can be disregarded here. It is 
 however important to remember that one may sometime 
 take an electrocardiogram of such a case, and then it is 
 simply necessary to plot out diagrammatically the time 
 relations of auricles to ventricles, the origin of the beats, 
 and see where this rhythm falls in the above classification 
 in which it must find its place. 
 
 There is a condition in which an independent ventricular rhythm 
 may occur however, and that is in complete heart block which will 
 be taken up directly. If for some reason the auricular ventricular 
 bundle is functionally destroyed so that no impulses pass from auricle 
 to ventricle, the ventricle is left to take on a rhythm of its own, 
 quite independent of, and uninterrupted by the auricle. In an 
 
CLASSIFICATION OF CARDIAC RHYTHMS 51 
 
 uncomplicated case of heart block, these ventricular impulses are of 
 the normal type, but in old diseased hearts cases have been reported 
 in which there is a regular ectopic ventricular rhythm, of a fairly 
 normal rate, about one hundred per minute, which is absolutely in- 
 dependent of the auricle, which beats at its own rate. Such a con- 
 dition is shown in figure 24. 
 
 SUMMARY OF ECTOPIC RHYTHMS 
 
 We see from this review of the different rhythms that 
 they are fundamentally the same, although giving very 
 different clinical results. That an ect opic rhvthm, appar - 
 ently mu st occur at a faster rate th a n normal t o prevent 
 the sino- auricular node breaking in and reesta blishing the 
 normal rhythm. That wheiLlh£jdaythmJs^once set up it 
 is of constant rate,- perhaps as it is not under nervous 
 controh_ That in the ectopic auricular rhythms we have 
 first a group, paroxysmaljackyca rdia, in which t he ventricle 
 follows JJTP nnririp Then a group in which the ventricle 
 is no linger f^l^lp tn k<^pp pnre wi th the auricle, aiirictd ar 
 flutter y^ and finally-ar-greup in which t he rate of impuls e 
 
 formation is; c;r> gr pat that thp ann Vle itself rnnno lxontract 
 
 coordinatfily^—anjcL-goes i nto a state of fibrillation . In all 
 of these auricular rhythms, these great variations of rate 
 are not extremely dangerous, as the ventricle can continue 
 to beat at such a rate that it can deliver enough blood to 
 keep up the circulation. WTien however the rhythm is 
 one in which the new rate controls the ventricle as well 
 as the auricle, the rate at which the rhythm can occur 
 must be such that the ventricle is able to maintain the 
 circulation, that is, a fairly slow rate, and this rate ap- 
 parently cannot occur without the sino-auricular node 
 breaking in, except in rare conditions, as for instance 
 auricular-ventricular nodal rhythm, and of complete heart 
 block in cases of ectopic ventricular rhythm. 
 
CHAPTER V 
 
 Abnormalities of Conduction prom Auricle to 
 Ventricle 
 
 We have seen that normally the auricular impulse is 
 transmitted from the auricle to the ventricle by the auric- 
 ular-ventricular bundle in about one-fifth of a second. 
 In cases of poisoning with chemicals, toxic conditions as 
 pneumonia, t3^hoid, etc., this bundle may be functionally, 
 partially or wholly destroyed. And in other conditions 
 of pressure or destruction by new growths, syphilitic 
 lesions, etc., it may be physically injured or destroyed. 
 Such impairment of conduction delays the conduction of 
 impulses and gives rise to three conditions all of which 
 are different degrees of the condition known as "heart 
 block." 
 
 1. Increased conduction time. In the first of these the 
 conduction time is simply increased; instead of being the 
 normal one-fifth of a second it may be increased to two- or 
 three-fifths of a second, but the ventricle follows each 
 auricular beat. 
 
 2. Dropped heats or partial block. If however the injury 
 to the bundle is greater, the delay in conduction will be 
 so great that the auricle will beat once or several times to 
 one beat of the ventricle. 
 
 3. Complete block, idio-ventricular rhythm. And finally 
 if the bundle is completely destroyed the auricle will beat 
 at its own rate and the ventricle will take on an independent 
 rhythm of its own. The first two of these conditions are 
 self-explanatory. If the conduction time is simply increased 
 the pulse will be of the same rate as the auricle and regular, 
 
 52 
 
ABNORMALITY OF CONDUCTION 53 
 
 and the abnormality will be sllo^\Tl by the use of some in- 
 strument only. If the ventricle follows each second or third 
 beat of the auricle, the pulse vdW be slow and regular, while 
 if it follows an irregular number of auricular beats it will 
 be irregular. 
 
 When however we have complete block a very distinct 
 clinical picture is found. During the estabhshment of the 
 independent \'entricular rhythm the patient goes through 
 a very trying transition period. He will pass through the 
 first two stages of heart block with no great difficulty, 
 but will then come to a condition in which the ventricle 
 must w^ait for a very long time before an auricular impulse 
 will pass through the bundle and set it off. At first this 
 may be for six or eight beats of the auricle. The ventricle 
 will become greatly distended with blood and the patient 
 will become conscious of the pause and the forcible beat 
 which will follow'. As the block to the passage of impulses 
 becomes more complete, there will be a still longer pause 
 and sometimes it will be as much as ten or fifteen seconds 
 before the ventricle will beat again. During this time the 
 patient will become unconscious but will regain conscious- 
 ness as soon as the heart begins to beat once more. Such 
 attacks may go on for a very long time before complete 
 block is established, and the ventricle takes up a rhythm of 
 its own. When this does happen the ventricle suddenly 
 begins to beat with great regularity, and at a very slow 
 and characteristic rate, about twenty-four to thirty times 
 per minute. The patient is at once relieved and usually 
 returns to very good health and may go about for many 
 years with often little disturbance. This independent 
 ventricular rhythm, usually called " idio-ventricular rhythm, " 
 gives normal ventricular complexes in the electrocardiogram, 
 which means that impulses arise somewhere in the bundle 
 
54 THE HEART RHYTHMS 
 
 above its bifurcation. Electrocardiograms of these differ- 
 ent rhythms are given below. 
 
 We have now considered rhythms arising from each of 
 the only areas into which the heart can be divided at present. 
 We have considered the factors which limit their numbers, 
 and it is hoped that from this description the reader will 
 have a true understanding of the rhythms of the heart. 
 This is the main object of this book. The rhythms are 
 
 Time.'/s 
 
 R R R R R 
 
 — A/U-^ .i.tiiii.i/V*wJU«^i.-M«A»>»JU*'''X*i»^.« ii/VlU^'S.i.» Ai«rlU 
 
 , a , , , , <? . *» . . . g . 
 
 p 
 
 ,JL 
 
 Time 'Is 
 
 Fig. 25. Curves showing abnormalities of conduction from auricle to ventricle. 
 I. Showing simple increase of conduction time in which each auricular beat is 
 followed after an abnormally long interval by a beat of the ventricle. II. Show- 
 ing a still greater disturbance of conduction in which one auricular impulse fails to 
 get through to the ventricle and this ventricular beat is dropped. III. Finally 
 a condition where the ventricle is completely cut off from the auricle and the two 
 beat absolutely independently of each other. 
 
 extremely simple, and if one will practice constructing 
 rhythms in which beats arise from the different areas, 
 using the limiting factors of regularity of beat, conduction 
 time, refractory period of the ventricle, and rate consistent 
 with life, one can very soon satisfy oneself as to what 
 rhythms can occur, and obtain a working knowledge of the 
 subject, which will allow him to reason out any individual 
 
ABNORMALITY OF CONDUCTION 
 
 55 
 
 case, rather than to have a few rhythms learned by memory 
 which one tries to apply to the case in hand. A diagram- 
 matic smmnary of the rhythms is given below. 
 
 .y\. 
 
 Sino Auricular Rhythms 
 (1) Normal Rhythm. 
 
 (a) Simple Tachycardia. 
 
 (b) Simple Bradycardia, 
 
 (c) Sinus Arrythmia 
 (2) Normal Rhythm Interrupted 
 
 by 
 
 (a) Ectopic Auricular Beats. 
 
 (b) Auricular Ventricular No- 
 dal Beats. 
 
 (c) Ectopic Ventricular Beats. 
 
 Ectopic Auricular 
 Rhythms 
 
 (1) Paroxysmal Tachycardia. 
 
 (2) Auricular Flutter. 
 (J) Auricular Fibrillation. 
 
 -III. Auricular Ventricular 
 Nodal Rhythms 
 Rare. 
 
 Ectopic Ventricular- 
 Rhythms 
 
 Incompatible with life except 
 in rare cases. 
 
 V. Abnormalities oj Con- 
 duction in any 
 rhythm. 
 
 Fig. 26. A diagrammatic summary of the heart rhythms. 
 
PART II 
 
CH.\PTER I 
 Interpretation of the Electrocardiogram 
 
 In the first part of this book it was hoped to give the 
 reader a knowledge of the heart rhythms, uncomphcated 
 by the details of diagnostic methods. In this second part 
 the object is to tell him what to expect from the use of the 
 different instruments for recording the heart rhythms. 
 A detailed description of their use is however not attempted. 
 It is assumed that the electrocardiograph gives complete 
 information in each case. It is then merely necessary to 
 point out the usual difficulties in obtaining a satisfactory 
 record. There is however no necessity for a long descrip- 
 tion of the use of the electrocardiograph. The instrument 
 is somewhat similar to an automobile. Almost anyone 
 can run one, but to obtain a knowledge of its parts takes 
 considerable study. The ordinary student or practitioner 
 cannot afford one of his own but should be able to have 
 an electrocardiogram taken, examine the record himself 
 and confirm the diagnosis given. In order that he will 
 know whether the record has been well taken or not the 
 following few essential points are given. 
 
 As the electrocardiogram gives us characteristic complexes 
 for impulses arising from each of the four differentiated 
 areas above mentioned, and shown in figure 15, it is 
 possible to determine at once from such a curve, the rate, 
 regularity, source of impulse formation of both auricular 
 and ventricular beats the length of conduction time, and 
 the interrelation of auricular and ventricular beats. Thus 
 we may obtain complete data from an electrocardiogram, 
 
 59 
 
60 THE HEART RHYTHMS 
 
 and can at once locate the condition with which we are deal- 
 ing in the above classification of cardiac rhythms. 
 
 There are however two conditions which at times offer 
 considerable difficulties in the interpretation of these curves : 
 those in which auricular impulses are not clearly indicated, 
 and other conditions where auricular impulses are obscured 
 by falling in the ventricular complex. 
 
 The first of these conditions is often remedied by taking 
 the so-called three leads. If two electrodes are placed at 
 the ends of a bundle of muscle fibers, and the muscle is then 
 
 Ri^hihm. ^^^^ ""^ /efAA 
 
 ^rm. 
 
 Left Leo. 
 
 Fig. 27. Showing the different angles at which the lines of electromotive force 
 cross the heart in the so-called "three leads," Lead I — ^R. A. and L. A. Lead 
 II— R. A. and L. L. Lead III— L. A. and L. L. 
 
 made to contract, a much greater deflection of the string of 
 the galvenometer occurs than when the electrodes are placed 
 at the sides of the bundle. In taking an electrocardiogram 
 it is customary to "lead off" the current from either or 
 both hands, or from the right or left hand, and the left 
 leg. It will be seen from figure 27 that in these different 
 leads the lines of electromotive force will cross the heart 
 at different angles. One of the leads may cross the heart 
 at a more advantageous angle than another, so that in case 
 auricular complexes are not clearly seen in one, it is well to 
 try another until a satisfactory result is obtained. 
 
THE ELECTROCARDIOGRAM 61 
 
 In case the auricular wa\-es are thought to be hidden in 
 the ventricular complexes, these three leads may be used in 
 hopes of depressing a portion of the ventricular curve and 
 bringing out the auricular complexes. If this is not possible 
 a change in rate may be attempted by cautious means 
 (making certain of course that it will not 'be injurious to 
 the patient). If these means also fail it is well to take a 
 long strip of curve to see if any irregularities occur, in which 
 case the auricular complex may show up between the beats. 
 If the heart remains perfectly regular the chances are very 
 great that the auricle is beating and controlling the rhythm. 
 WTiether the auricular impulses are of sinus or ectopic origin 
 can however not be ascertained in that condition. One 
 is then left to judge whether this is the case or not by other 
 means, as the history, s}Tnptoms, change from day to day, 
 which of course does not come directly under the heading 
 of interpretation of curves. 
 
 The beginner may adopt some such routine examination 
 of curves as the follo\\ing in order not to overlook anything. 
 
 1. Examine the time curve. See if the intervals are 
 equal, in other words whether the paper runs at an even 
 rate. This is important. 
 
 2. Locate auricular complexes if possible. 
 
 3. Locate ventricular complexes. 
 
 4. If auricular complexes are present (they are absent 
 in auricular fibrillation and auricular-ventricular nodal 
 rhythm only) see if they are of normal or ectopic origin, 
 equidistant, or irregular. Note the rate. 
 
 5. See if a ventricular complex follows each auricular 
 complex and note the length of conduction time. (The 
 distance between auricular and ventricular complexes.) 
 See if this is normal (about one-fifth second) and if it is 
 constant throughout the curve. 
 
62 
 
 THE HEART RHYTHMS 
 
 With these data we can determine the rate and rhythm 
 of the auricle and of the ventricle, and the time relation of 
 contraction of one to the other. That is, whether we have 
 a regular auricular rhythm, a gradual variation in rate of 
 auricular rhythm (sinus irregularity) or whether the regular 
 rhythm is suddenly broken. We can tell the same of the 
 ventricle. From the conduction time we can determine 
 the condition of the conduction system. Finally we note 
 the form of complexes, whether of normal or ectopic origin. 
 We then decide which of the five general types of rhythm 
 we are dealing with (sino-auricular, ectopic auricular, 
 auricular-ventricular nodal, ectopic ventricular, or heart 
 block). 
 
 X^-JU^-Ju 
 
 *i M s 
 
 H S 
 
 Fig. 28. Diagrammatic scheme for showing auricular and ventricular beats 
 and the conduction time. The upper heavy line represent auricular contrac- 
 tion and the lower ventricular, while the slanting line gives the conduction time. 
 
 In compHcated cases it may help the beginner to represent 
 the curve diagrammatically. A strip of paper may be 
 laid along the curve as in figure 28 and the time of auric- 
 ular and ventricular complexes marked off on it in vertical 
 lines. Connect the auricular to ventricular lines by slant- 
 ing lines as in the figure, and let these represent the conduc- 
 tion time. In this case it is evident that the auricle is 
 beating regularly, that the conduction time gradually in- 
 creases until one ventricular beat is dropped. This method 
 of diagrammatically representing the beats is much used, 
 and the construction of such a curve may make it more 
 simple to see just what condition we are dealing with in 
 compHcated curves. 
 
THE ELECTROCARDIOGRAM 63 
 
 One other point remains to be spoken of, and that is the 
 form of ventricular complexes. One needs to look at 
 very few electrocardiograms to see that the form of the 
 complexes, especially those of ventricular origin, vary 
 greatly. It is usually simple to tell whether they are of 
 normal or of ectopic origin, but it is not simple to tell just 
 where they arise. By a careful study of these complexes, 
 taken ^^ith the different leads, information may be obtained 
 as regards right and left cardiac hypertrophy, lesions of 
 the right and left bundle, the position of the heart, etc. This 
 information although valuable, has nothing to do with 
 cardiac rhythm, and the reader is referred to more advanced 
 books for the study of these problems. 
 
CHAPTER II 
 
 The P0LYGIL4PH, Sphygmograph, and Pulse 
 
 Instruments. In studying tracings taken with these in- 
 struments we are deahng with curves made by recording the 
 mechanical filhng of the vessels by blood pumped from the 
 different heart chambers. It is at once evident that these 
 curves will give only the time of contraction of auricle and 
 ventricle, and not the point of impulse formation as shown 
 in the electrocardiogram (as both a normal and ectopic 
 beat will give an equally good pulse wave). Furthermore 
 the shape of the curves is not characteristic, so that by 
 glancing at a tracing we cannot pick out auricular and 
 ventricular waves. Finally the recording and shape of 
 these curves depends upon the sensitiveness of the appara- 
 tus, the skill of the operator in adjusting it, and extraneous 
 factors such as movements of the patient, the apparatus, 
 etc., all of which may cause extra waves in the curves 
 or absence of expected waves. The recording and inter- 
 pretation of polygraphic tracings will be found to be much 
 more difficult and inexact than the making and interpre- 
 tation of electrocardiograms. 
 
 The most important and helpful point in the interpre- 
 tation of these curves is to know exactly how many points 
 in the curve can be fixed with certainty, how many more 
 by one's knowledge of heart physiology, and how much 
 must be left to one's judgment. The interpretation of 
 polygraphic tracings is not a complete and exact science. 
 Certain facts can be established, often enough for a complete 
 interpretation, more often however the facts of the curve are 
 not enough to make a diagnosis certain but can be used as 
 a diagnostic aid only. 
 
 64 
 
POLYGRAPH AND SPHYGMOGRAPH 
 
 65 
 
 The instruments in use are of several types but all are 
 based on two principles. In one the radial pulse is taken 
 by means of a small spring which rests on the radial artery. 
 The pulse w^ave raises the spring, compresses the air in a 
 tambour connected to it, and transmits this wave to a 
 second tambour to which is attached the writing lever. 
 
 In the other t>^e an arm cuff is used, which is placed 
 about the arm over the radial artery. This cuff is attached 
 
 Fig. 29. Diagrammatic scheme of arm cuff method of recording the arterial 
 pulse curve. The letter a represents the arm cuff; b the bulb to fill it with air; 
 c the manometer with which to take the arterial pressure; d a rubber ball to 
 take up this heavy pressure; e a glass container in which the pulse waves reaching 
 d are transmitted to the air at low pressure to the tambour /, which records them 
 by means of the lever g on the revolving drum. 
 
 by a rubber tube, to a recording tambour. On account of 
 the high arterial pressure a bulb is interposed between the 
 cuff and the tambour to take this pressure off the recording 
 tambour as shown in figure 29. In this figure a is the arm 
 cuff, h the bulb to fill it with air, c, the manometer to re- 
 cord the pressure, and d, the bulb to take up this pressure. 
 WTien the cuff is blown up to the proper pressure (some- 
 where between the diastolic and systolic pressures), each 
 
66 
 
 THE HEART KEYTHMS 
 
 pulse wave causes d to expand, compresses the air in e, 
 a closed glass chamber connected with the tambour / 
 and the writing lever g, which records each pulse wave. 
 A mercury manometer is also attached to the instrument, 
 which is useful in taking the blood pressure, but also is 
 of help because the cuff may be blown up until the best 
 arterial pulse is obtained, the pressure recorded, and then 
 the venous tambour arranged. When the time comes to 
 
 19 
 
 No. 43076 
 Fig. 30. The Mackenzie polygraph, with horizontal pens. 
 
 make the arterial tracing it is only necessary to blow up 
 the cuff to the pressure noted before, turn on the tambour, 
 and one is sure of obtaining a good radial curve. 
 
 The first of these methods requires more time and trouble 
 in adjusting the spring to the pulse. This is often annoying 
 when trying to take a tracing quickly after exercise, etc. 
 The latter method requires no skill in adjustment as the 
 cuff is merely shpped over the arm and blown up. It 
 can be attached at once and gives beautiful records. 
 
POLYGRAPH AND SPHYGMOGRAPH 
 
 67 
 
 c &- 
 
 
 3 C 
 tn TO 
 
 C 
 
 a E 
 
 W in 
 3 C 
 
 s ° 
 
 IS 
 
 OJ ■'-> 
 C ^ 
 « in 
 
 " .S 
 •J 10 
 
 S to !5 
 
 I "^ 
 
 (I) 4> 
 
 S o 
 
 .§ e 
 
 N ■" 
 
 
68 
 
 THE HEART RHYTHMS 
 
 The venous pulse is recorded by placing a small glass 
 funnel or other cup receiver, over the veins of the neck. 
 The air is transmitted to a tambour, and writing lever 
 similar to that used with the radial pulse, and described 
 on page 65. 
 
 The tambours are all of the same general type, but some 
 use a horizontal, others a vertical pen. The horizontal 
 
 No, 43104 
 
 Fig. 32. The Jaquet polygraph, a very beautiful instrument, which is attached 
 to the wrist. 
 
 pen is good when one is accustomed to it, but with the be- 
 ginner it is constantly coming off the paper. With the 
 vertical levers the pens hang on the paper and cannot come 
 off, and when in good condition give excellent curves. 
 
 The two types of instrument most often used are the 
 Mackenzie with horizontal pens, which is a beautiful 
 machine and compact, and a newer type the Zimmermann 
 (fig. 31), with arm cuff attachment, vertical pens, and blood 
 
POLYGILA.PH AND SPHYGMOGRAPH 69 
 
 pressure attachment. This is by all means the simplest 
 machine as no difficulty is found in obtaining a good radial 
 tracing. The pens cannot come off the paper, and the 
 instrument is so constructed that tracings may be made on 
 rolls of smoked paper, or on plain paper with ink. 
 
 Another very beautiful instrument is the Jaquet (fig. 
 32) which is a deHcate httle affair which is attached to the 
 wrist. One has to use small strips of smoked paper, and 
 although it is as beautifully built as a watch it is not as 
 convenient for ordinary use. 
 
 THE RADIAL PULSE 
 
 Let us return once more to our original diagram of the 
 heart (fig. 33). 
 
 We see that the left ventricle is the only heart chamber 
 which sends blood into the aorta, and consequently all 
 arterial pulses are indices of left ventricular contraction only. 
 Any arterial pulse curve (that is radial, brachial, temporal, 
 etc.) will show the following points (fig. 34). 
 
 An upstroke (1), a sharp apex (2), a plateau broken by 
 a notch (3), a downstroke reaching normal at (4), Let us 
 now see to what causes these various parts of the curve 
 are due. 
 
 The upstroke (i) is due to ventricular systole, sending 
 a wave of blood down the artery. The end of this upstroke 
 is seen in a sharp point (2), which will vary in shape and 
 size with the weight of the lever, the sensitiveness of the 
 tambour used etc. It is not then a constant, and is of 
 no importance. The notch (J) is the so called dicrotic 
 notch. It occurs at the end of systole at the time when 
 the ventricle relaxes. Various explanations have been 
 given for its origin but we may think of it unscientifically 
 
70 
 
 THE HEART RHYTHMS 
 
 Mackenzie Ink Polygraph, New American Model 
 
 Jaquet Portable Polygraph 
 
POLYGRAPH AKD SPHYGMOGRAPH 
 
 71 
 
 as a back kick of the blood when the ventricle stops forcing 
 it into the aorta, and relaxes, the arterial pressure becomes 
 then relatively higher than in the ventricle, and slaps back 
 
 fiorta and Arte rial PJses. 
 
 Fig. a. Same as figure 1. Diagrammatic representation of the origin of the 
 arterial pulse. 
 
 Fig. 34. Same as figure 3. Three types of arterial pulse curves showing the 
 different forms of the curve which are unimportant as long as the beginning of sys- 
 tole (/) and the dicrotic notch (J), the end of systole, are to be seen. 
 
 on the aortic valves. In any case it occurs at the end of 
 systole. The point (4) where the curve returns to normal, 
 is a variable, it depends upon how full the arteries are when 
 
72 THE HEART EHYTHMS 
 
 the pulse wave comes down it, etc. It is of no use to us 
 and should be entirely disregarded. 
 
 In the radial pulse curve we have then two points of 
 importance only, everything else may be disregarded. 
 These two points are: 
 
 1^ The upstroke marking the beginning of ventricular 
 systole. 
 
 2. The dicrotic notch, marking the end of ventricular 
 ■systole. 
 
 Curves should be so taken that these two points come out 
 clearly. If they do not the curve is of no use. Whether 
 the rest of the curve is large or small is merely a matter of 
 beauty, but is of no consequence. 
 
 THE VENOUS PULSE 
 
 In taking a venous curve the patient should lie flat 
 (if possible), with a small pillow under the head in such a 
 position that the sterno-cleido mastoid muscle is relaxed. 
 The receiver is best placed over the lower end of this muscle 
 on the right side, just above and at the inner end of the 
 clavicle. One is tempted to place the receiver higher up 
 where the veins are more prominent, but in most cases 
 this will not give as good a curve. No fixed rule can how- 
 ever be given for this, and the best position will have to 
 be found for each patient. 
 
 Having obtained a venous tracing we find a curve in the 
 normal individual, similar to that shown diagrammatically 
 in figure 35. An actual polygraphic tracing is shown in 
 figure 4. The shape of the curve is of no importance, 
 and it varies in each case, and in the same case depending 
 entirely upon the adjustment of the instruments. It is 
 however necessary to know what to look for in these curves, 
 
POLYGRAPH AND SPHYGMOGRAPH 75 
 
 and to take them with the object of bringing out the es- 
 sential points instead of making a beautiful appearing 
 tracing which may lack the few points necessary for a 
 diagnosis. Nothing very definite can be made out of 
 such a curve. The waves are not of characteristic shape 
 or size, we cannot, therefore, identify any one of them as 
 being due to some particular portion of the cardiac cycle. 
 It is then evident that the venous curve alone is of Httle 
 
 Fig. 35. Same as figure 4. A normal polygraphic tracing showing that the 
 venous curve gives no waves of characteristic shape by which the auricular beats 
 could be distinguished from those of the auricle. 
 
 value to us, and before taking up the analysis of such 
 curves let us represent diagrammatically (fig. 36) a cardiac 
 cycle, the heart being shown as ha\dng but one auricle 
 and one ventricle, and the great veins as a tube entering 
 the auricle from above. 
 
 If one uses the imagination a trifle it may be possible to 
 make out from this series of figures the sequence of events 
 taking place in the auricle and ventricle, and the cause of 
 the different venous and radial pulses. 
 
74 
 
 THE HEART RHYTHMS 
 
 At (i) both auricle and ventricle are partially filled with 
 blood. At (2) the auricle contracts, as indicated by the 
 heavy outline, and forces its blood into the ventricle, 
 distending the latter. This contraction of the auricle is 
 accompanied by a back wave up the vein, and a rise in the 
 
 Fig. 36. Diagrammatic scheme showing the cause of the venous and arterial 
 pulse waves. At (1) both auricle and ventricle are partially filled with blood. At 
 (2) the auricle contracts as shown by its heavy outline, and forces blood into 
 the ventricle, distending it. At the same time it sends a wave up the veins to the 
 neck and causes a rise in the venous curve, the a wave. At (J) the auricle relaxes 
 as shown by the irregular outline and the ventricle contracts and drives the blood 
 out into the aorta. This contraction causes a wave in the venous curve, the c wave 
 at the beinning of systole. The ventricular pulse wave does not reach the wrist 
 until one-tenth of a second after the corresponding wave in the neck, due to the 
 time taken to travel there. At (4) the ventricle is still contracting and the auricle 
 filling with blood. This causes backing up of blood in the veins and a rise in the 
 venous curve. At (5) the ventricle relaxes, end of systole, and the blood falls 
 from the auricle into the ventricle causing a sharp drop in the venous curve, the 
 V wave (really a drop in the curve). At the same time the dicrotic notch occurs 
 in the arterial pulse. At (6) both the auricle and ventricle are passively filling 
 with blood, and at (1) the cycle is begun again by contraction of the auricle. 
 
POLYGR.\PH AND SPHYGMOGILA.PH 75 
 
 venous curve at (a). The letter {a) is used in these curves 
 to denote auricular waves. It is placed at the upstroke 
 of the waves as are all polygraphic measurements, as the 
 end of the upswing depends, as before stated upon the sen- 
 sitiveness of the writing lever, etc., and is not constant. 
 The auricle immediate^ relaxes as indicated by the irregular 
 outline in (J), and blood runs into it from the great veins 
 causing a fall in the venous curve. At (3) the ventricle 
 contracts and forces blood out into the aorta as indicated 
 by. the arrow. Simultaneously with this contraction there 
 is an upstroke in the venous curve (c). The letter c was 
 first used to denote carotid pulse. It was formerly thought 
 that the curve c was due to the receiver being held over 
 the carotid artery, but experiments in dogs with no carotid 
 artery give this same wave, so that it may be due to a 
 back wave up through the auricle to the vein. 
 
 One-tenth of a second later the upstroke at 5 occurs in the 
 radial tracing, this delay being due to the time taken by the 
 pulse wave to travel from the heart to the radial artery. 
 The reference (4) shows another stage in the middle of 
 ventricular systole. It will be noticed here that during 
 systole no blood can pass from auricle to ventricle, there- 
 fore the auricle fills up, and as it fills blood gradually backs 
 up in the veins above it depending upon conditions in 
 the general circulation. On this account the venous 
 curve after the quick up and down wave due to systole 
 of the ventricle, will gradually rise to the point v. This 
 rise may be small or if the veins are very full it may be a 
 sharped peaked curve. It is important to remember this 
 as one is othenvise often puzzled by the variations in this 
 wave. 
 
 At (5) the ventricle relaxes (end of ventricular systole) 
 as shown by the irregular line. As it does so the pressure 
 
76 THE HEART RHYTHMS 
 
 within it falls, and the accumulated blood in the auricle 
 rushes down into the empty ventricle, not from a contrac- 
 tion of the auricle, but merely on account of the blood there 
 being at a higher pressure than in the empty ventricle. 
 This is accompanied by a sudden drop in the venous curve 
 denoted by v (ventricular wave). One often speaks of the 
 a, c, and v waves. At v we really have a drop in the venous 
 curve, not an up wave. On account of the filhng of the 
 veins during ventricular contraction the venous curve may 
 rise giving a sharp peak just before v, but at this point the 
 curve should show a sudden fall. At the same time (not 
 one-tenth of a second later) the dicrotic notch occurs 
 in the radial tracing. 
 
 The ventricle and auricle then both gradually fill, and 
 the cycle is repeated. 
 
 One should practice drawing a complete set of diagrams 
 for oneself until he is familiar with the course of events 
 in a cardiac cycle as there is no use in attempting to interpret 
 polygraphic curves without understanding this completely. 
 
 From a study of the above curves it will be seen that we 
 can fix four points with certainty. These are, 
 
 1. Beginning of ventricular systole in the radial curve 
 (upstroke S). 
 
 2. End of systole in the radial curve (dicrotic notch d). 
 
 3. The beginning of systole may be plotted onto the ven- 
 ous curve by marking a point one tenth of a second earher 
 in the venous curve (upstroke c). 
 
 4. The end of systole may be plotted on the venous 
 curve by measuring up directly from the dicrotic notch. 
 This gives (y) at the beginning of the downstroke of the 
 wave. 
 
POLYGR.\PH AND SPHYGMOGR.\PH 77 
 
 In this figure the pens for both cun^s are writing directly over 
 each other, as shown by the ordinates x and y, Hnes made by moving 
 each pen on the paper to record their relative positions. In all 
 curves these ordinates are necessary and all measurements are made 
 from them. For example in this curve with the pens directly over 
 each other, the point v is over d. If however the pen for the venous 
 curve were not directly over the arterial pen, v would not come over 
 d. In order to plot d onto the venous curve, its distance from y 
 would be measured, this distance would then be laid off from x 
 along the venous curve and v fixed. These ordinates must be given 
 with each tracing or it is of no use. 
 
 No other points can be fixed. With polygraphic tracings 
 we axe then able to fix the beginning and end of systole 
 in the radial curve, and have an exact method for determin- 
 ing the rate and rhythm of the left ventricle if all the beats 
 are transmitted to the wrist. In many cases however 
 of weak and irregular hearts the small premature beats send 
 too small a pulse wave to be felt or recorded at the wrist, 
 and one of the first things which must be done in polygraphic 
 tracings is to compare the radial pulse with the cardiac 
 impulse or heart sounds to determine if any beats fail to 
 reach the wrist. 
 
 In the normal venous pulse curve there are three waves 
 in each cycle, and we are able to fix two of these from plot- 
 ting them from the radial curve, namely the beginning and 
 end of systole. The third wave in the cycle should be due 
 to contraction of the auricle, but we have no way of fixing 
 it. From our knowledge of heart physiology however we 
 have two points which help us to decide about these auricu- 
 lar waves, one is that: 
 
 1. Auricular waves occur at regular intervals. The two 
 exceptions being a gradual variation in rate due to sinus 
 arrhythmia, or to a sudden break in the rhythm due to pre- 
 mature ectopic beats. 
 
78 THE HEART RHYTHMS 
 
 2. Auricular waves occur normally about one-fifth of 
 a second before the carotid waves. 
 
 If then we are given a polygraphic curve to interpret 
 we first fix the beginning and end of systole on the radial 
 curve, plot these points onto the venous curve with exact- 
 ness marking each of them regardless of where they fall, 
 mark them c, and v, and then plot points one fifth of a second 
 before the c points and mark these with a ? mark. These 
 are the only possible points which one can fix, and the in- 
 terpretation must be made from them. 
 
 Next one should see if waves occur at the points where 
 the a waves are to be expected. If they do, mark them with 
 a if no other waves are left unaccounted for one is then in 
 possession of sufficient data to make a diagnosis. If how- 
 ever other waves occur in the venous pulse which cannot 
 be accounted for by the fixing of the above points, the 
 only things which other waves can be are auricular waves 
 or artefacts, or if the a waves occur slightly out of place, 
 or some or all of them are absent the only way to make a 
 diagnosis is to plot out just what we really have, and then 
 see with which one of our known cardiac rhythms this best 
 agrees. It is self evident that without a complete knowledge 
 of all cardiac rhythms it is useless to try and make a diagno- 
 sis by exclusion. 
 
 Let us take one or two curves as examples. 
 
 Before taking a tracing each pen should be swung back 
 and forth to give the ordinates x and y, their relative posi- 
 tions on the paper, as described above. If they are so 
 arranged that they are just over each other, then the points 
 on the radial curve can be plotted vertically onto the venous 
 curve, if however they are not over each other as is usually 
 the case, the points on the radial curve may be transferred 
 to the venous curve by taking a strip of paper laying it 
 
POLYGRAPH .\ND SPHYGMOGRAPH 
 
 79 
 
 along the radial curve, marking the ordinate x and the 
 points 5 and d of each pulse curve. Then by laying this 
 paper on the venous curve mth the ordinate x on the 
 ordmate y the points 5 and d may be marked off onto the 
 venous curve and given their proper lettering c and v. 
 The c points will however all be moved back {towards the 
 ordinate) one-tenth of a second to allow for the time taken for 
 the pulse wave to reach the wrist as already described. 
 
 One should then measure the time intervals as recorded 
 by the time marker and notice if they are all equidistant, 
 
 Tirm /; 
 
 s s s s s s 
 
 Fig. 37. A normal polygraphia curve, showing the plotting of the beginning and 
 end of systole onto the venous curve, the c and v points, and the probable location 
 of the auricular waves at points one fifth of a second before the c waves. These 
 are the only points which we can fix in the polygraphia curves. 
 
 in order to tell if the paper is running evenly. Slight varia- 
 tions in the rate of movement of the paper often give very 
 confusing curves if this is not checked up. 
 
 Next we mark off points one-fifth of a second before the 
 c points, which is easily done as the time intervals in most 
 polygraphs is one-fifth of a second. These points are 
 marked with a ? mark. We have now fixed all the points 
 which we can and we are ready to interpret the curve. 
 
 At the points c we should have an up wave in the curve, 
 due to the carotid beat, and at the points v, there should be 
 a decided fall in the curve, for the reasons described above. 
 
80 
 
 THE HEART RHYTHMS 
 
 At the points marked with the ? we should expect to find 
 upward curves which are the auricular beats. In the curve 
 under examination we find that all these factors occur as 
 we expect and that there are no other waves which are un- 
 accounted for, the a-c interval or conduction time is normal 
 and we may then feel quite certain that we are dealing with 
 a normally beating heart. 
 
 Time 'Is 
 
 s s 
 
 Fig. 38. Another illustrative curve showing the location of the c and v waves 
 and the marking of the points where the a waves should normally come, one-fifth 
 of a second before the c waves. It is found that waves occur in the venous tracing 
 near the normal points for the a waves but not exactly at these points. These 
 waves are however equidistant from one another, and all but one are followed by a 
 ventricular beat. The curve would show a gradual increase of conduction time 
 with a dropped ventricular beat after the fourth auricular beat if it were not for 
 the two waves at r. It has already been found that all ventricular beats are 
 transmitted to the wrist, so that these cannot be ventricular beats, they are out 
 of time for auricular beats and they are not followed in the radial curve by ven- 
 tricular beats, so that they are neither auricular or ventricular beats and must 
 be due to some mechanical movement of either the patient or the instrument. 
 
 If however we have a curve as shown in figure ?>^, com- 
 plications will arise. 
 
 Here again we examine the time marker, measure off 
 the points 5 and d on the radial curve, plot these from the 
 ordinates onto the venous curve, remembering that the 
 point c will come one tenth of a second before s. Mark 
 points one fifth of a second before the c points on the ven- 
 ous curve with ? marks, and then examine the curve. 
 
POLYGRAPH AND SPHYGMOGRAPH 81 
 
 In the first place we find that the ventricular radial beats 
 are not regular. We know that there are several causes 
 of ventricular irregularity but the one which it is important 
 to think of at once is whether there is absolute irregularity, 
 that is auricular fibrillation. If this condition is present 
 there ^\dll be no auricular waves. Examining the curve 
 for auricular waves which should fall in a normal heart 
 at the points marked wth a ?, we find that there is a wave 
 at the first mark, and a small wave near each of the others 
 except next to the last one where the curve is very irregular. 
 If one now starts with the first of these waves which are 
 thought to be auricular waves and tests their regularity 
 by measuring the distance between them it will be found that 
 they are all equidistant and that there is one wave falling 
 in the right interval which is not followed by a ventricular 
 wave. If one measures the distance from the beginning 
 of each of these waves to the point c (the a-c distance) 
 representing conduction time from auricle to ventricle, it 
 will be found that it gradually increases up to the one which 
 is not followed by a ventricular beat, and that the next 
 auricular wave which is followed by a ventricular beat 
 is of the original a-c distance. We have then a gradually 
 increasing a-c distance, or a lengthened time of conduction, 
 and in one instance a dropped ventricular beat, in other 
 words we are dealing with a case of partial heart block. 
 
 We now examine the curve and see if anything remains 
 unaccounted for, and we find a double curve in the venous 
 tracing at r, which we have not yet accounted for. This 
 must be either an auricular or ventricular beat or an arte- 
 fact. The wave at r, is not followed or accompanied by 
 a ventricular beat, each apex beat is transmitted to the 
 wrist, it does not come at the regular auricular time; it 
 is therefore neither a ventricular or auricular beat but must 
 
82 THE HEART RHYTHMS 
 
 be due to some mechanical disturbance of the levers, as 
 coughing, moving, etc. 
 
 Each curve must be worked out in some such systematic 
 way as this. The important points to remember are to 
 first see that the time marker is running evenly, then fix 
 the beginning and end of systole in both the radial and 
 venous curve, and lay off the points where the auricular 
 beats should arise; having done this next look for auricular 
 waves which should be equidistant except where there is 
 a gradual variation in their rate due to sinus arrhythmia, 
 or a decided and abrupt change due to premature beats. 
 
 A review of these different methods of recording the heart 
 rhythms shows us that the electrocardiograph gives us 
 complete information. It is merely necessary to take a 
 curve, plot out the auricular and ventricular beats, their 
 time relations to each other, and the points of origin of the 
 impulses and one will be able to locate the rhythm in its 
 proper place in our classification. With the polygraph our 
 information is always incomplete. We may be able to 
 tell the time relations of the auricular and ventricular 
 beats, but we cannot tell the point of origin of impulses 
 directly. For instance it is impossible by the tracing alone 
 to distinguish between the ectopic-auricular beats of paroxys- 
 mal tachycardia, and the normal auricular beats of a rapidly 
 beating heart. It is on this account that it is essential 
 to have a complete knowledge of the heart rhythms to 
 interpret a polygraphic or sphygmographic curve. In 
 order to aid one in getting a clear picture of all these different 
 rhythms the following diagrammatic curves of each type 
 of heart rhythm are given. The polygraphic curve is given 
 and below it the auricular and ventricular beats plotted out 
 in a diagrammatic scheme. As such curves give also the 
 sphygmographic tracings one can use the same curves in 
 discussing this instrument, and the arterial pulse. 
 
CIL\PTER III 
 
 POLYGRAPHIC CURVES 
 I. SINO-AXIRICULAR RHYTHMS 
 
 a. Normal heart heat. This has been taken up so often 
 before that it is unnecessary to repeat the curve, it is im- 
 portant to remember however that the auricular beats 
 occur at regular intervals, that they are followed in one- 
 fifth of a second by the ventricular beats, and that in plot- 
 ting the beginning of ventricular systole onto the venous 
 curve the point c will come one-tenth of a second earlier 
 in the venous curve, while the point v is plotted up directly 
 from the dicrotic notch, finally to remember to plot all 
 points from the ordinates x and y. 
 
 b. Simple tachycardia. Here there is an increased auric- 
 ular rate, the conduction time will remain normal, the 
 increase in rate will be found to be due to shortening of the 
 diastoHc interval. The rhythm will be regular. 
 
 c. Simple bradycardia. The slow heart rate is here ar- 
 rived at by a lengthened diastoUc period, but the conduction 
 time will be found to be normal. The rhythm is regular. 
 
 d. Sinus-arrhythmia. Here the rate of auricular beats 
 undergoes a gradual variation due to direct chemical or 
 nervous stimulation of the sino-auricular node. The change 
 in rate will always be found to occur gradually, no sudden 
 break ever occurring. Such a rhythm is shown in figure 
 39 and it is seen that the gradual variation in rate is due to 
 changes in rate of the auricular beats. The conduction 
 time is normal and the pulse curve shows a gradual change 
 in rate. 
 
 83 
 
84 
 
 THE HEART RHYTHMS 
 
 Timz'/s. 
 
 \ \ \ \ \ \ 
 
 a o 
 
 Fig. 39. Sinus arrhythmia. 
 
 c V ^ c V c^ V 
 
 C_ V a 
 
 Time'/s 
 
 Fig. 40. Ectopic-auricular beat. This occurs prematurely and is followed by 
 a normal auricular beat which occurs also in a shorter interval than normal. The 
 normal rhythm is then interrupted by two beats. 
 
 Tima'/s'- 
 
 ^ ^ ^ ^ ^ "^ 
 
 Fig. 41. This is another curve of a premature ectopic-auricular beat which is 
 followed by the normal auricular beat in such a time that the regular rhythm is 
 broken only by the one premature beat. 
 
 Time,'/^'. 
 
 \ \ SIS s^ 
 
 Fig. 42. Curve of an ectopic auricular- ventricular nodal beat, which occurs 
 prematurely and is followed in such time by the normal auricular beat that the 
 normal rhythm is interrupted by two beats. 
 
POLYGR.\PHIC CUR\^ES 85 
 
 n. ECTOPIC BEATS INTERRUPTING NORMAL RHYTHMS 
 
 a. Ectopic-aiiricidar beats. In all of these ectopic beats 
 we have a normal regular rhythm interrupted by single or 
 multiple beats of ectopic origin. It will be noticed that 
 there are never any extra beats but that a beat occurs 
 prematurely. Such a beat is shown in figure 40 and 42. 
 
 The normal point of origin of impulses is the sino-auricular 
 node the auricle beating first and the ventricle following it, 
 we therefore always look at the auricular heat first, and work 
 out the rhythm from it. Here we see that we have a regu- 
 larly beating auricle interrupted at L by an auricular 
 beat coming prematurely, this is followed in a shorter time 
 than the regular auricular rhythm by another auricular 
 beat and then the regular auricular rhythm is again 
 established at the original rate. 
 
 Each auricular beat is followed in the normal time by 
 a ventricular beat so that the radial curve shows the same 
 irregularity as the auricular rhythm. Two heats are out 
 of time. This is due to the premature beat and to the normal 
 auricular beat following, occurring also prematurely. All 
 of this is easily seen in the polygraphic curve but it is im- 
 portant to compare the two radial beats which are out of 
 time with the one beat which we will find out of time in the 
 radial tracing, when we have an ectopic beat of other origin. 
 
 In figure 41, however a curve is given in which we have 
 an ectopic-auricular beat the same as in the above curve, 
 in which the auricular beat following the premature one 
 comes in the normal auricular interval. In this case only 
 one auricular and one ventricular beat is out of time and 
 it cannot be distinguished from the ectopic beats of other 
 origin. 
 
 b. Ectopic auricular-ventricular nodal heats. An ectopic 
 beat of auricular-ventricular nodal origin is shown in 
 
86 
 
 THE HEART EHYTHMS 
 
 figure 42. Here the regular rhythm is interrupted by a 
 premature beat arising from the auricular-ventricular 
 node. Both the auricle and ventricle beat at once. This 
 is shown by the abnormally large venous wave occurring 
 at the time of ventricular contraction while the radial 
 pulse wave is if anything smaller than normal. The next 
 auricular beat from the sino-auricular node may occur 
 as in the case of the ectopic-auricular beat, either slightly 
 earlier than normal or in the normal time, in which case there 
 may be either one or two beats out of time in the radial 
 curve. 
 
 Tirm'/s 
 
 \ \ \ .' \ \ 
 
 Fig. 43. Ectopic-ventricular beat. Here the rhythm is interrupted by the 
 premature ectopic-ventricular beat only. The next auricular beat falls in the 
 refractory period of the ventricle and this fails to respond but does so to the next 
 auricular beat. 
 
 c. Ectopic-ventricular heats. In this condition there is 
 no abnormality of the sino-auricular node therefore we 
 will find a regularly beating auricle. Each auricular beat 
 will be followed by a ventricular beat in the normal time 
 until we have one ventricular beat occurring prematurely 
 as shown in figure 43. When the next auricular impulse 
 comes to the ventricle it finds it in the refractory state and 
 it cannot contract, so that this auricular beat will not 
 be followed by a ventricular beat, but the next auricular 
 impulse finds the ventricle again ready for contraction, 
 and it is followed by a ventricular beat. We have then 
 
POLYGRAPHIC CURVES 87 
 
 only one interruption to the normal rhythm, and that is 
 the single premature ventricular beat. 
 
 This rather lengthy description is given to enable one 
 to differentiate by means of the sphygmograph alone an 
 ectopic-auricular from an ectopic-ventricular beat. It will 
 however be seen that the auricular and auricular-ventricular 
 nodal beats may both give a single interruption to the 
 regular rhythm which is exactly similar to the interruption 
 caused by a premature ventricular beat. The only diagnos- 
 tic point of any value is then, that if the regular rhythm is 
 interrupted by two beats in succession the ectopic beat is 
 not of ventricular origin but of either ectopic-auricular 
 or auricular-ventricular nodal origin. The origin of any 
 ectopic beat may however be determined by the use of the 
 electrocardiograph . 
 
 III. ECTOPIC-AURICULAR RHYTHMS 
 
 a. Paroxysmal tachycardia. Here we have a very fast 
 regular rhythm of ectopic origin, all of the auricular beats 
 arising from an ectopic focus in the auricle. They are 
 followed in the normal or slightly reduced conduction time 
 by normal ventricular beats. The polygraphic curves can 
 in no way be distinguished from a fast beating normal heart, 
 as the auricular beats arise at regular intervals, and each is 
 followed by a ventricular beat. Such a curve is shown in 
 figure 44. 
 
 h. Auricular flutter. In this condition the auricle is 
 contracting at regular intervals and at such a fast rate that 
 it is impossible for the ventricle to follow it. Two conditions 
 may then result as shown in figures 45 and 46. In the first 
 the ventricle may follow a regular number of auricular 
 beats giving a regular pulse which may be of fairly normal 
 
THE HEAUT RHYTHMS 
 
 vOl'c Ov at c ^•' r "a '^/N''/V<^/\'k 'j 
 
 Timers'. 
 
 Fig. 44. Curve of paroxysmal tachycardia which will be seen to be indis- 
 tinguishable from a rapid normal rhythm. 
 
 Timz'/s" 
 
 V V ' S" S" V V'V " 
 
 Fig. 45. Curve of auricular flutter. The ventricle follows a regular number of 
 auricular beats and gives a regular slow ventricular pulse. 
 
 Tone. 'Is 
 
 Fig. 46. Auricular flutter in which the ventricle follows an irregular number of 
 auricular beats and is very irregular. 
 
 Tiim'js 
 
 III \ % I 
 
 Fig. 47. Curve of auricular fibrillation in which no auricular waves are seen, 
 and the ventricle beats absolutely irregularly. 
 
POLYGRAPHIC CURVES 89 
 
 rate. In the second condition the ventricle follows an 
 irregular number of auricular beats and will then show all 
 manners of irregularity. Sometimes pulses can be made 
 out in which the ventricular beats occur in groups following 
 first three, then four auricular beats. If such regular 
 groupings occur in the radial pulse one feels that there must 
 be a controlling factor; that there must be a beating auricle, 
 and that the ventricular rhythm must be due either to a 
 condition of auricular flutter, or to heart block, which will 
 be taken up later, the principle being the same however, 
 the ventricle following first one number and then another 
 of auricular beats. In flutter this irregular beat of the 
 ventricle is due to its being unable to maintain the auricular 
 rate, while in the case of heart block the conduction is so 
 poor that all auricular impulses do not reach the ventricle. 
 
 c. Auricular fibrillation. In this condition there is no 
 coordinate contraction of the auricle, no auricular waves 
 can therefore be made out. The venous curve will show 
 simply c and v waves due to the beginning and end of ventric- 
 ular systole. As there is no regular auricular rhythm but a 
 very irregular auricular impulse formation the ventricle 
 will respond to only those irregular impulses which reach 
 it and its rhythm will be one of absolute irregularity. Such 
 a curve is shown in figure 47. 
 
 IV. AimiCULAR-VENTRICULAR NODAL RHYTHM 
 
 This is an exceedingly rare condition. The impulse 
 for contraction arises at the auricular-ventricular node 
 and is transmitted to the auricle and ventricle in the 
 same length of time so that the auricle and ventricle 
 beat simultaneously. In such a case the a and c waves 
 would occur at the same time and make one wave, no 
 separate a waves would appear, and the venous curve 
 
90 
 
 THE HEART RHYTHMS 
 
 would consist only of the combined a and c wave and 
 the V wave. The rhythm would be regular as all un- 
 interrupted rhythms are, and therefore we would have 
 a regular arterial pulse. The simultaneous beat of the 
 auricle and ventricle give an abnormally high and 
 sharp wave occurring at the beginning of ventricular 
 systole, while the arterial pulse wave is of the normal size 
 as shown in figure 48. The diagnosis of this condition has 
 to be made with caution, if the polygraph alone is used. 
 It is based on having a regular rhythm, no auricular com- 
 
 Tiim'/s 
 
 ! ! 1 I : I 
 
 Fig. 48. Curve of auricular- ventricular nodal rhythm, in which the ventricle 
 bdats regularly and gives an abnormally high c wave in the venous curve. No 
 auricular waves are visible. Car<^ should be taken in making a diagnosis of auric- 
 ular-ventricular nodal rhythm from such a curve alone, as a very similar 
 curve may be obtained by placing the venous receiver over the carotid ar^^ery and 
 missing the venous curve altogether in a normally beating heart. 
 
 plexes, and an unusually high c wave. But one can see 
 that it is perfectly possible to place the venous receiver on 
 the neck in such a way that one will be able to record carotid 
 beats and not record the venous pulse at all, in which case 
 of course no auricular beats could be seen. The condition 
 is so rare that one mil hardly ever see it, and most all cases 
 in which a regular ventricular venous pulse is found with 
 no signs of auricular waves, will be found, if an electrocardio- 
 gram is taken, to be due to the manner in which the venous 
 curve was taken. In fact in the hands of the beginner 
 
POLYGRAPHIC CURVES 91 
 
 more than half of the tracings taken will be found to con- 
 sist of nothing but the carotid pulse instead of the venous 
 curve. 
 
 V. ECTOPIC-VENTRICULAR RHYTHMS 
 
 We haA'e seen that if runs of ectopic beats arise in the 
 ventricle they must be rapid or the auricle breaks in and the 
 normal rhythm is set up again. On the other hand if 
 the run of ectopic beats is rapid and prolonged the circula- 
 tion fails and the patient becomes unconscious and dies. 
 There is then a very narrow limit of rates within which it 
 is possible to have ventricular rhythms compatible mth 
 life, and we may from a practical point of view consider 
 that they do not occur. They are theoretically possible 
 however. 
 
 VI. ABNORMALITIES OF CONDUCTION FROM AURICLE 
 TO VENTRICLE 
 
 a. Prolonged conduction time. In certain conditions of 
 toxic poisoning, or pressure, the conduction from auricle 
 to ventricle is impaired and it takes the impulse more than 
 the customary one-fifth of a second to pass from auricle 
 to ventricle. If this lengthened conduction time is not too 
 great the ventricle will still follow each auricular beat, 
 and the curve will show no changes from the normal except 
 an increased a-c interval. Such a curve is given in figure 
 49. The arterial pulse will be perfectly regular and no 
 abnormahty can be made out without the ^•enous tracing 
 being taken. 
 
 b. Dropped heats or partial block. If the impairment of 
 conduction increases so that all auricular impulses are not 
 transmitted to the ventricle it will be found that every 
 once in awhile one ventricular impulse will be dropped, as 
 shown in figure 50. 
 
92 THE HEART RHYTHMS 
 
 Polygraphic tracings give us complete information in such 
 cases as the auricular and ventricular waves are both shown, 
 and the conduction time may be measured. The arterial 
 pulse may however be very deceptive. The gradual in- 
 crease in conduction time makes a slight lengthening of 
 time between the arterial beats, and an interval where the 
 beat is dropped. Single beats are easily recognized by 
 
 Time'/s 
 
 ■^ ^ ^ -^ ■-. ^ 
 
 Fig. 49. This shows a simple prolongation of the conduction time but each 
 auricular beat being followed by a ventricular beat. 
 
 Timers' 
 
 Fig. 50. In this curve the conduction time is prolonged after each of the first 
 three beats until the fourth, where the auricular impulse does not reach the ventricle 
 and one ventricular beat is dropped. The next auricular beat passes to the ventricle 
 and the cycle is repeated. 
 
 these factors. Where beats are dropped at regular or 
 recurrent intervals the condition may be made out from 
 the radial pulse alone. For instance if each fourth beat 
 is dropped, one will find a gradual lengthening of the in- 
 terval between beats, and then a dropped beat, the sequence 
 of events being repeated regularly. Or one may find a 
 gradual increasing distance between the radial beats, and 
 then a dropped beat occurring after first three and then four 
 
POLYGR.\PHIC CUE.\TS 93 
 
 auricular beats alternately. But when the ventricle follows 
 no regular number of auricular beats, the pulse curve loses 
 all signs of regularity and the condition cannot be told by 
 the arterial pulse alone from the absolute irregularit\' of 
 auricular fibrillation or of multiple ectopic beats. 
 
 c. Complete block. Finally we have a condition of com- 
 plete block, which has been described above in which no 
 auricular beat can reach the ventricle and the ventricle 
 takes on a rhythm of its own, known as an idio-ventricular 
 rhythm. This rhythm is characteristic, as no other con- 
 dition (except in cases of poisoning) gives such a slow ven- 
 
 FiG. 51. This curve shows a condition of complete block in which the auricle 
 and ventricle beat absolutely independently of each other. The ventricular rate 
 is characteristic of this condition being a little over twenty per minute. 
 
 tricular rate. It is usually between twenty-four and thirty 
 beats per minute, but may be higher. A curve of such a 
 condition is shown in figure 51. Auricular waves are shown 
 occurring at regular intervals, and bearing no relation to 
 the ventricular beats which occur at long and perfectly 
 regular intervals. 
 
 SUMMARY OF POLYGRAPHIC RHYTHMS 
 
 If we summarize this review of the polygraphic tracings 
 we find that it is possible to make the following diagnoses 
 with this instrument. 
 
 Sino-auricular rhythms. Complete information can be 
 obtained of all these rhythms but a simple tachycardia 
 
94 THE HEART EHYTHIIS 
 
 cannot be distinguislied from parox}'smal tachycardia by 
 the tracing alone. 
 
 Ectopic beats. These may all be recognized, and the origin 
 of the ectopic beat located, that is whether it is auricular, 
 auricular-ventricular nodal, or ventricular. 
 
 Auricular-veniricuJar nodal rhythms. These cannot be 
 proven to occur as the diagnosis is based on the absence 
 of auricular waves, and abnormally large c waves, both of 
 which factors may be obtained in a poorly taken normal 
 rhythm in which the venous receiver is placed over the 
 carotid arter}* and no v'enous pulse is recorded. The con- 
 dition is extremely rare. 
 
 ECTOPIC-AI"MCrL-\R RHYTHMS 
 
 Paroxysmal tachycardia. This caimot be differentiated 
 from simple tachycardia by this instnmient alone. 
 
 Auricular flutter. This may give ver\- beautiful auricular 
 waves, and an even better picture than the electrocardio- 
 gram. Sometimes however the waves are ver}- hard to 
 obtain. 
 
 Auricular fhrilhtion. In this condition no auricular 
 waves occur and the ventricle beats with absolute irregular- 
 itv'. One is never certain that the absence of auricular 
 waA'es in the curve is not due to the technique of taking the 
 tracing. The other two possibilities are multiple ectopic 
 beats, and irregular heart block. These of course would 
 be shown m the venous curv'e if one were sure that the 
 venous curve were being taken, but it is surprising in 
 how many cases the begumer is unable to obtain anvthing 
 but a carotid tracing instead of the venous curve. 
 
 HEART BLOCK 
 
 -\11 Stages of heart block may be shown perfectly by poly- 
 graphic tracings. 
 
POLYGRAPHIC CURVES 95 
 
 SUMMARY OF SPHYG MO GRAPHIC TRACINGS 
 
 Sphygmographic tracings give us graphically the same 
 information which we can obtain by feeling the pulse. Our 
 information is very limited, and unless it is combined with 
 other clinical signs and s>Tnptoms is of limited use, but 
 with a good knowledge of the heart rhythms, and a clear 
 picture of the clinical conditions associated with each, 
 which one can obtain by experience only, the pulse will 
 be found to be of great diagnostic aid. It gives of course 
 only ventricular beats. 
 
 All regular rhythms cannot be differentiated except by their 
 rate. Such rhythms are the normal beat, simple tachycardia, 
 simple bradycardia, paroxysmal tachycardia, auricular 
 flutter, in which the ventricle follows a regular number 
 of auricular beats, auricular-ventricular nodal rhythm, 
 and heart block in which the ventricle follows a regular 
 number of auricular beats. 
 
 Sinus arrhythmia may be easily recognized by the gradual 
 variation in distance between the individual beats. 
 
 Ectopic heats if occurring singly may be recognized as 
 such. The normal rhythm is interrupted by one beat oc- 
 curring prematurely, and sometimes a second one, the only 
 break in the regular rhythm any of the three t>T)cs of 
 ectopic beats, namely ectopic-auricular, auricular-ventricu- 
 lar nodal, or ectopic-ventricular, may give the same picture. 
 If howe\^er the premature beat is followed by a second 
 beat at an interval shorter than the normal period, and the 
 regular rhythm then restored, we know that the ectopic 
 beat is not of ventricular origin. It may be an ectopic- 
 auricular or an auricular-ventricular nodal beat, but the 
 two cannot be differentiated. 
 
96 
 
 THE HEART RHYTHMS 
 
 Absolute arrhythmia is always associated with fibrilla- 
 tion but it may occur in multiple ectopic beats, or irregular 
 heart block. 
 
 Periods of regular beats may occur in partial heart block, 
 but also in runs of ectopic beats. 
 
 CONSTRUCTION OF DIAGRAMMATIC CURVES 
 
 In conclusion a method of construction of these dia- 
 grammatic curves is given as a help to those who wish to 
 plot out the rhythms for themselves. Such a scheme is 
 given in figure 52. 
 
 Fig. 52. Diagrammatic method of constructing polygraphic curves which will 
 be found described in the text. 
 
 One saves a great deal of time by using a drawing board 
 and T-square. First the nine parallel construction lines 
 are ruled off in pencil. The first one for the plotting of the 
 venous curve, the second for the top of the arterial pulse 
 curve, the third for the dicrotic notch in this curve, the 
 fourth as a base line for the same curve, the fifth for the 
 time marker, the sixth and seventh for the top and bottom 
 of the auricular diagram, and the eighth and ninth for the 
 top and bottom for the ventricular diagram. 
 
 Time intervals are laid off along the time marker fine 
 at regular intervals. One-half inch for each fifth of a second 
 
POLYGRAPHIC CURVES 97 
 
 will give a convenient working scale. One can calculate 
 quickly the intervals at which to put the auricular beats for 
 any given rate by deciding how many to put in a three 
 second interval, this number multiplied by twenty wall 
 give the rate per minute. For instance three, a rate of 
 sixty, four, one of eighty, etc. Having decided on the rate, 
 let us suppose the auricular beats will fall at two-inch in- 
 tervals. The ruler is then laid along the venous line 
 (1), and marks made at two-inch intervals and marked 
 (a). One-fifth of a second after each of these will come 
 the ventricular waves which should be marked by points, 
 in this case one-half inch after the (a) points. The duration 
 of ventricular systole is a little more than the conduction 
 time or the a-c interval, and so points are made, let us say 
 three-quarters of an inch after the c points and lettered v 
 marking the end of systole. We now have all the beats 
 plotted out. Construction lines are now drawn down from 
 each of these points across all the horizontal lines. Points 
 one-tenth of a second after each c line are marked on the 
 base line of the radial pulse curve. The ventricular beats 
 are now drawn in, starting each upstroke at these points, 
 and putting in the dicrotic notch at the proper place, 
 shown by the construction line from "?;. " The venous 
 curve can then be drawn making upstrokes at the a, and 
 c points, and down strokes at the v points. Finally the 
 diagrammatic lines for the auricular and ventricular beats 
 may be drawn in. 
 
 From such a construction it will be seen that the venous 
 curve gives us the true relation of the beats to each other. 
 That all our rhythms are based on the auricular beats, 
 the normal controlling pacemaker of the heart, and the time 
 relations of ventricular beats to these auricular beats plotted. 
 The method which we must adopt in reading a tracing is 
 
98 THE HEART KEIYTHMS 
 
 however the reverse, on account of the absence of charac- 
 teristic venous curves. In a tracing we must first start 
 with the ventricular beat as shown in the arterial curve, 
 because it gives us our only two fixed points, the beginning 
 and end of systole, and from these plot backwards so to 
 speak onto the venous curve in order to distinguish there, 
 auricular from ventricular waves. 
 
INDEX 
 
 Arrythmia, sinus, 37. 
 Auricular beats : 
 
 premature, 37, 85. 
 
 ectopic, 85, 94. 
 Auricular: 
 
 complex, 30. 
 
 fibriUation, 45, 89, 94. 
 
 flutter, 43, 87, 94. 
 
 "a" waves, 17, 74. 
 Auricular ventricular. 
 
 bundle, 29, node 33. 
 
 nodal beats, 39, 85. 
 
 nodal rhythm, 48, 89, 94. 
 
 Beats: 
 
 dropped, 52, 91. 
 
 ectopic auricular, 37. 
 
 ectopic auricular ventricular 
 39, 85. 
 
 ectopic ventricular, 40. 
 
 premature, 38. 
 Block: 
 
 partial, 52, 91, 94. 
 
 complete, 52, 93. 
 Bradycardia, simple, 36. 
 Bundle: 
 
 auricular ventricular, 29. 
 
 of His, 29. 
 
 "c" wave, 16, 74. 
 Carotid wave, 16, 74. 
 "Circus" movements, 47. 
 Complex, 20. 
 
 auricular, 30. 
 
 ventricular, 30. 
 Conduction, 27, 52. 
 
 time, 28, 52. 
 Curves: 
 
 construction of, 62, 96. 
 
 examination of, 61. 
 
 polygraphic, 16, 64, 83. 
 
 sphygmographic, 14, 95. 
 
 nodal. 
 
 Dropped beats, 52, 91. 
 Dicrotic notch, 69. 
 
 Ectopic beats: 
 
 auricular, 37, 40, 85. 
 
 auricular ventricular nodal, 39, 85. 
 
 ventricular, 40, 86. 
 Ectopic rhythms: 
 
 auricular, 41, 87, 94. 
 
 auricular ventricular nodal, 48, 89, 94. 
 
 ventricular, 49, 91. 
 Electrocardiogram, normal, 20, 31. 
 
 interpretation of, 59. 
 Electrocardiograph, 19. 
 "Extra Systole," 38. 
 
 Fibrillation. 
 
 auricular, 45, 89, 94. 
 
 ventricular, 49. 
 Flutter, auricular, 43, 87, 94. 
 
 Heart beat: 
 
 normal, 36. 
 
 polygraphic curve of, 17, 74. 
 Heart block: 
 
 complete, 52. 
 
 partial, 52. 
 His, bundle of, 29. 
 
 Idio-ventricular rhythm, 52. 
 
 Leads, 60. 
 
 Node: 
 ■ auricular ventricular, 33. 
 
 sino-auricular, 32. 
 Nodal beats, auricular ventricular, 39. 
 Normal : 
 
 electrocardiogram, 20. 
 
 heart beat, 36. 
 
 rhythm, 36. 
 
 99 
 
100 
 
 INDEX 
 
 Orclinates, 77. 
 
 Paroxysmal tachycardia, 42, 87, 94. 
 Period, refractory, 27. 
 Premature: 
 
 auricular beats, 37, 85. 
 
 auricular ventricular nodal beats, 
 39, 85. 
 
 beats, 38, 94. 
 
 ventricular beats, 40, 86. 
 Polygraph, 16, 65. 
 Polygraphia curves, 83. 
 
 inteipretation of, 78. 
 Pulse, the, 13. 
 
 radial, 13, 16, 69. 
 
 venous, 17, 73, 74. 
 "P" wave, 20. 
 
 "QRS"wave, 20. 
 
 Radial pulse, 13, 14, 69. 
 Refractory period, 27. 
 Rhythms : 
 
 auricular ventricular nodal, 48, 89, 
 
 94. 
 ectopic auricular, 41, 87, 94. 
 ectopic ventricular, 49, 87, 91. 
 
 normal, 35. 
 sino-auricular, 35, 93. 
 
 Simple bradycardia, 36. 
 Simple tachycardia, 36. 
 Sinus arrhythmia, 37, 83. 
 
 Sino-auricular node, 32. 
 Sino-auricular rhythm, 35, 93. 
 Sphygmograph, 14. 
 Sphygmographic curves, 95. 
 String, 20. 
 Systole, "extra" 38. 
 
 "T" wave, 20. 
 Tachycardia: 
 
 simple, 36. 
 
 polygraphia curve of, 83. 
 
 paroxysmal, 42, 87, 94. 
 
 "V" wave, 17, 74. 
 Venous pulse, 17, 73. 
 Ventricular beats: 
 
 premature or ectopic, 40, 86. 
 Ventricular: 
 
 beats, premature or ectopic, 40, 
 
 complex, 30. 
 
 fibrillation, 49. 
 
 rhythm, ectopic, 49. 
 
 idio-ventricular, 52. 
 
 wave, 74. 
 
 Waves : 
 
 auricular, 17, 74. 
 carotid, 16, 74. 
 "P,"20. 
 "QRS,"20. 
 "T,"20. 
 "v," 17, 74. 
 
DUE DATE 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 201-6503 
 
 
 Printed 
 in USA 
 
J. 
 
 COLUMBIA UNIVERSITY LIBRARIES 
 
 0037552147