movements. The rate of speed at which the paper is unrolled can be changed so that a tracing can be taken of almost any length and at various speeds. While taking tracings the instrument should be stopped at intervals and cross lines made on the paper with both pens, so as to have fixed points to measure from in analyzing the tracings. A normal tracing is shown in Figure 2. The lower tracing marked "radial" shows the pulsations of the radial artery, and the upper tracing marked "venous" shows the movements of the jugular veins and carotid artery. The venous tracing is obtained by placing the receiver over the jugular bulb on the right side, which is a little above and one inch outside the sterno-clavicular joint. In the study of an arterial tracing there are only a few points to be considered. It is important to note that all of the beats are the same size and an equal distance apart. The small notch "N" in the down stroke is due to the closing of the aortic valve and coincides with the opening of the auriculo-ventricular valves. The space "E" between the two vertical lines is the period of ventricular systole while the semilunar valves are open. In a normal venous tracing there are three elevations or waves for each cardiac cycle. The cause of each wave can be determined by finding its relation to some known event in the radial tracing. The pulse in the carotid, for obvious reasons, precedes slightly, about onetenth of a second, the pulse in the radial. Therefore, the distance from the cross line in the radial tracing, to one-tenth second of any up-stroke, is measured with a caliper, and the wave in the venous tracing corresponding with this distance from the cross line in the venous tracing is due to the pulsation in the carotid and is marked "c." The bottom of the aortic notch is exactly the same distance from the lower cross line that the wave which follows c is from the upper cross line and is marked "v" on account of its being a ventricular wave. The wave which precedes c by about one-fifth of a second is caused by the systole of the auricle and is marked "a." As the a wave occurs with the beginning of the auricular systole and the pulsation in the carotid artery is practically simultaneous with the beginning of the ventricular systole, the distance between a and c, the a-c interval, represents the time it takes the impulse to pass from the auricle to the ventricle over the bundle of His. One not familiar with pulse tracings usually becomes confused by the venous tracing, but the fact is that nearly all irregularities can be diagnosed by careful analysis of the arterial tracing alone. According to Mackenzie and Lewis, all the heart irregularities can be placed in the seven following groups: 1. Sinus arhythmia. 4. Pulsus alternans. 5. Paroxysmal tachycardia. 6. Auricular flutter. 7. Auricular fibrillation. GROUP I. SINUS ARHYTHMIA In sinus arhythmia the impulses are not formed regularly in the sinus; hence, there are irregular contractions of auricles as well as of ventricles. It is also called "youthful arhythmia," "respiratory arhythmia" and "functional arhythmia"; but perhaps the best term is "vagal arhythmia," because it is always due to altered. tone of the vagus. The irregularities in childhood are nearly always of this type. Friberger in 321 unselected schoolchildren between the ages of 5 and 14 found a moderate degree of this form of irregularity in 63 per cent., and in 12 per cent. the irregularity was marked. It is by no means uncommon in neurotic adults, and it is not infrequently confused by physicians with other forms of arhythmia caused by organic heart disease. Its recognition is usually quite easy, as on forced respiration the pulse rate becomes rapid on inspiration and slow on expiration. Figures 3 and 4 are typical instances of this form of arhythmia. By comparing this tracing with each of the other forms of arhythmia, it is readily seen that it does not bear a close resemblance to any of them. The patient from whom this tracing was taken is a vigorous youth of 14. I was asked to see him because his physician had advised against exertion of all kinds. This advice the patient was inclined not to accept, because he was a leader in athletics in school and never noticed that he was short-winded. A careful examination failed to reveal any signs of organic heart disease. The diagnostic features of sinus arhythmia are its relation to respiration, its frequency in youth and neurotics, and its disappearance when the heart rate is increased by exercise or by atropin. This form of arhythmia has been described as a diagnostic sign of tuberculous meningitis in childhood; but here it is only a sign of vagal irritation, and more marked in childhood on account of the unstable vagal tone in youth. Regarding the prognosis of this form of disturbed rhythm, Dr. Mackenzie, who has been in Figure 5. The small beat "p" represents the premature contraction of the ventricle. It is smaller than the normal beat, because the ventricle contracts so early that only a small amount of blood is expelled into the aorta. Sometimes the quantity of blood in the ventricle is not sufficient to open the aortic valves, in which case there will be no pulse in the artery; but auscultation of the heart during the pause in the pulse will reveal a heart sound due to closure of the auriculo ventricular valves. Note in the venous tracing in Figure 5 that Badial м ли www Fig. 2.-Normal tracing of the radial and jugular pulses. The small notch marked "N" represents the closure of the aortic valves and the opening of the auriculo-ventricular. In the venous tracing there are three waves for each cardiac cycle. The first, "A,' is due to the systole of the auricle, the second, "O," due to the pulsation in the carotid, and the wave marked "V" is caused by the storing of blood in the auricle while the ventricle is in systole and the auriculo-ventricular valves are closed. The short ventricle lines at the top of the tracing are made by the time marker which is recording the time in intervals of two-tenths of a second. wwwwwwwwwwwwwth Fig. 3.-Sinus arhythmia, showing the relation of the irregularity to respiration. GROUP II.-EXTRASYSTOLE This group comprises the most common form of arhythmia in the adult. The irregularity is due to what is commonly known as extrasystole; but, as the disturbance in rhythm is due to a premature systole rather than to an extrasystole, the term "premature contraction" suggested by Mackenzie seems to be the better one. This form of arhythmia is described in the older text-books as an intermittent pulse, and it is usually the cause of the irregularity when the patient says his pulse "skips a beat occasionally." The origin of the impulse may arise in either the ventricle or the auricle and sometimes, although rarely, in the node of Tawara. The ventricular premature contraction is by far the most common, and an example of the disturbance of rhythm produced by it is shown traction is that the distance between the preceding beat and the succeeding beat is always the same as in two ordinary beats. When the premature contraction arises in the auricle, it is usually followed by a ventricular response, the compensatory pause being absent, as shown in Figure 6. We have little knowledge of the causes of premature contractions: in some cases they recur frequently; in others they are rare events; in some cases they are observed after every few beats throughout a life-time, and in others they seem to occur only in spells. Experimental research by Knowl and Hering demonstrated that increased intracardiac pressure as the result of constriction of the aorta. or of the pulmonary artery, or reflex stimulation of the vasomotor system, would induce 3. Hering: München. med. Wchnschr. premature contraction. Undoubtedly, any excessive rise of intracardiac pressure may induce an extrasystole, especially if the heart is unduly irritable, but their frequency in neurotics, when there is no reason to assume increased intracardiac pressure, would suggest that hyperexcitability of the myocardium, due to a neurosis, is a sufficient cause for their occurrence. The causes given for extrasystole by most writers are neurosis, excessive use of tobacco, coffee or tea, auto-intoxication, and too much of any of the drugs of the digitalis group. Tobacco is not an uncommon cause. The nored. As a rule, if the nature of the irregularity is explained to the patient, no further treatment will be required. The drugs of most value are atropin and the bromids. GROUP III-HEART-BLOCK In this group are the cases with an abnormal rhythm due to a disturbance in the function of the bundle of His. The block may be complete or incomplete. When the block is complete, no impulses reach the ventricle from the auricle, so that the stimulus for ventricular contraction is formed in the ventricle itself. In this case www.wwwwwww Fig. 4. Sinus arhythmia, the long pauses marked "X" be ween the "A" waves show that the auricles participate in the irregularity. patient from whom the tracing in Figure 5 was obtained, smoked from fifteen to twenty cigars a day. There is no proof, either experimental or clinical, that alimentary auto-intoxication can in any way disturb the rhythm of the heart. That overdosage of digitalis, or any of its allies, is the cause of extrasystole, is a point of the greatest importance. Figure 7 is an example of the toxic effects of digitalis in producing an extrasystole after every physiological beat. This is the so-called coupled rhythm or pulsus the pulse is always slow, usually less than 36, and, as a rule, regular. When the block is incomplete, the impulse for contraction of the ventricle comes down from the auricle, but there is a delayed transmission over the bundle. This may cause a missed beat occasionally, or there may be two, three or four contractions of the auricle to one of the ventricle, giving a 1:2, 1:3 or 1:4 block. The cause is usually some disease of the junctional tissue. According to Lewis, one-third of the cases in the adult are webmatrananbqaimipuulam lig. 5.-Extrasystole. The small beats "P" are due to the ventricular extrasystole. The distance from "A" to "B" is the same as from "A" to "C." "D" is the compensatory pause. In the venous tracing, where a falls on c, the peaks are unusually high, due to the auricles and ventricles contracting together. bigeminus of Hering. Extrasystoles are extremely rare under 12 years of age, unless produced by some drug of the digitalis group. They seldom occur when the pulse rate is above 100. Patients with this form of arhythmia may complain of a "stopping of the heart," a "thud in the chest," or a "peculiar sensation in the brain," due in all probability to the large amount of blood thrown into the arteries with the contraction that follows the long pause. This form of arhythmia is not in itself a sign of heart disease, and patients presenting it may never develop any signs of cardiac insufficiency. In looking for signs of organic heart disease, the occurrence of an occasional, or even frequent, extrasystole should be completely ig due to syphilis. I have seen two cases that completely recovered on antisyphilitic treatment. It is a disease common to old age, and in patients presenting it the heart usually shows calcareous deposits or connective tissue changes in the bundle. It may occur in childhood due to infectious diseases. In diphtheria the cause is usually hemorrhage into the bundle. Lewis has found that a mild grade of block is not uncommon in rheumatic endocarditis. There is no doubt that stimulation of the vagus with drugs of the digitalis group, direct pressure on the nerve in the neck, or reflex stimulation as in swallowing, will produce a heart-block. When the block is complete the condition is easily recognized clinically by the slow and regular pulse, the rate being usually less than 40, and the more frequent pulsations in the jugular vein. In the tracing shown in Figure 8 the block is complete everywhere except at the place marked "." At this point the ventricle responds to the impulse from the auricle, but the a-c interval is markedly prolonged, being two-fifths of a second instead of one-fifth of a second, the maximum normal period. In this case the auricular rate was 90 and the ventricu lar 42, a little more than a 2:1 block. Fig. 6.-Auricular extrasystole. The irregularity is due to premature contraction of the auricle. distance from "A" to "B" is less than from "A" to "C." When the block is incomplete, convulsions may occur from anemia of the brain giving rise to the Stokes-Adams syndrome. Cessation of ventricular contraction for thirty seconds or longer is sufficient to cause a convulsion. A missed beat due to incomplete heart-block may be recognized clinically by auscultating the heart and hearing no sound produced by contraction of the ventricle during the pause, such as occurs in a missed beat due to an extrasystole. The prognosis in heart-block is usually bad. However, when the block becomes complete, patients may live for a number of years and have a fair amount of cardiac efficiency. When The GROUP V.-PAROXYSMAL TACHYCARDIA This group includes a form of arhythmia characterized by paroxysms of rapid and regular heart action due to pathological impulses. It has been quite positively demonstrated that the impulses do not arise in the sinus, but in some new focus of impulse formation which may be either in the auricle or ventricle. The paroxysms vary in duration from a few minutes to four or five days. The onset and offset of an attack is always quite sudden and nearly always with a long pause, due to an extrasystole. The tracing shown in Figure 10 shows the long pause at the end of an attack, which is followed by a normal rhythm. Fig. 7.-Ventricular extrasystole due to digitalis intoxication. bigeminus. due to syphilis, good results may be obtained by antisyphilitic treatment. If caused by stimulation of the vagus, the block may be removed by a hypodermic injection of 60 of a grain of atropin. In incomplete heart-block, all drugs of the digitalis group are contra-indicated as they lessen the function of the bundle and consequently increase the block. When the block is complete and signs of loss of tonicity are present, digitalis may be given as the vagus has little or no influence on the ventricle, so the digitalis will do no harm. GROUP IV.-PULSUS ALTERNANS This rather rare form of arhythmia is characterized by alternation in the size of the beats, Every physiological beat is followed by an extrasystole pulsus The cause of this form of arhythmia is not well understood. The fact that there may be recurring attacks for years, without any other signs of heart disease, suggests the possibility of disturbed innervation. Lewis, who has done a vast amount of experimental work to solve the problem of etiology, is strongly of the belief that there is some intrinsic cause in the heart itself, and explodes the older views of withdrawal of vagal inhibition or accession of sympathetic influences. The same author was able to produce paroxysms of tachycardia in a dog by ligation of the coronary arteries, especially the right. The heart rate during a paroxysm varies from 120 to 200, and the rate is little influenced, if any, by position or emotion. During the attack the patient complains of a fluttering sensation in the chest; the blood-pressure falls 15 to 25 millimeters, and there is considerable lessening of cardiac efficiency as evidenced by lessened response to effort and by the fairly constant appearance of alternation as shown in Figure 10. Various therapeutic measures have been recommended, such as an ice-bag to the precordium, inverting the patient and direct pres clinically in patients with myocardial degeneration. It usually affects patients beyond middle life and may come on quite suddenly following exertion or emotion. Mackenzie believes that paroxysmal tachycardia is closely allied to auricular flutter, and that the vast majority, but not all cases, of the former are examples of the latter. It may occur in paroxysms of a few hours', or a few weeks' duration, or, after it is once established, it may persist throughout a life-time. معلنة عن المثال wwwww Fig. 8.-Heart-block. The ventricle is forming its own beats the auricle. The ventricle rate is 42 and the auricular, 90. sure on the right vagus in the neck. As the basis of all therapeutic measures is the increase of inhibition, the administration of a rapidly acting drug to stimulate the vagus would seem to be the logical remedy. In this respect there is nothing that excels the action of strophanthin given intravenously. The patient from whom the tracing in Figure 10 was obtained had been suffering from an attack of paroxysmal tachycardia for twentyeight hours. The ordinary therapeutic measures being of no avail, he was given 100 of a grain of strophanthin intravenously, and the paroxysm terminated abruptly, as shown by the long pause in the tracing, twenty-eight minutes after the injection was given. except at "X," where it apparently responds to an impulse from The usual symptoms are moderate lessening of cardiac efficiency, but sometimes there may be well-marked signs of heart failure. The condition may be suspected when the pulse rate is between 90 and 150 without an obvious cause. Cases with this form of arhythmia respond pulse. Sometimes the digitalis produces a quite readily to digitalis with a slowing of the fibrillation of the auricle, and after the drug is discontinued the rhythm may become normal. GROUP VII.-AURICULAR FIBRILLATION Working with the electrocardiograph, Lewis and Rothberger and Winterberg in 1909 made the very important discovery that the cause of a completely irregular pulse is fibrillation of the илл GROUP VI.-AURICULAR FLUTTER Fig. 9.-Pulsus alternans. In 1911 Jolly and Ritchie reported three cases with a disturbance of rhythm characterized by a tachycardia of the auricle. In the last two years a number of cases have been reported by Mackenzie, Lewis, Fulton and others. In this form of arhythmia the diagnosis cannot be made without mechanical means. The chief feature is the rapid auricular rate, which is usually between 200 and 340. Occasionally, although rarely, each auricular contraction is followed by a ventricular response, but as a rule the rate of the ventricle is between 90 and 140. This condition can be produced experimentally by faradic stimulation of the auricle and occurs 4. Jolly and Ritchie: Heaert, 1911, ii. auricles. Fibrillation of the ventricles is not compatible with life; according to Hering, it may be one of the causes of sudden death. A marked irregularity of the pulse as a common finding in many cases of heart failure has attracted the attention of clinicians for many years, and has passed by the terms pulsus mitralis, delirium cordis, pulsus irregularis perpetuis and nodal rhythm, all of which terms are now obsolete. main in diastole; hence, the absence of the a When the auricles are fibrillating, they rewave in the plebogram and the p wave in the electrocardiogram. Inspection of a fibrillating auricle shows the muscular fibers in a state of constant fine, fibrillary contraction, which reminds one of the fine tremor of the muscles of 5. Lewis: Heart, i, 1909. |