Exercise Electrocardiography as an Estimation of Cardiac Function

DISEASES Volume 51

0/ the

CHEST

APRIL, 1967

Number 4

Exercise Electrocardiography as an Estimation of Cardiac Function ARTHUR

M.

MASTER, M.D., F.C.C.P.* AND ISADORE ROSENFELD, M.D., F.C.C.P.**

New York, New York

C

workersl reported 83 per cent of those with symptoms of myocardial ischemia manifested normal tracings. In our own experience, approximately 47 per cent of patients with angina pectoris have normal pre-exercise tracings. These observations provide convincing enough evidence of the need for a reliable and objective, yet safe and practical test of cardiac function.' One often hears that the history is paramount in the diagnosis of angina. When classic, this is true. But there are many exceptions to the typical story, and we have found that differentiation between chest pain due to myocardial ischemia and that secondary to noncardiac or functional complaints may not always be possible by a detailed history alone even if taken meticulously by an experienced physician and recounted by a patient who is literate, cooperative, and honest. Although 80 per cent of patients with impaired coronary flow will describe the classic symptoms of the disease, the history is equivocal or atypical in the remianing 20 per cent of patients. For example, although effort is generally more apt to cause chest symptoms in the coronary artery disease group than in the "functional" group, this is not always so, and physical strain or certain movements of the body or thorax can produce pain as, for example, in cervical and dorsal arthritis. Again, while excitement and emotional stress are well appreciated causes of angina, on occasion they will be the sole precipitants,· and ordinary physical

ORONARY ARTERY DISEASE IS NOT

only the most important disease in the civilized world, but also the most publicized, and complaints of pressure, pain or discomfort in the chest, arms and back are commonly encountered by the physician. Doctor and layman alike are aware of the possible serious significance of these symptoms. However, their origin is not limited to coronary artery disease. They may also occur in noncardiac conditions such as (1) neuromusculo-skeletal disorders of the trunk, e.g., spondylitis, arthritis, neuritis, fibrositis, chondritis, myositis, as well as (2) gastrointestinal dysfunction, e.g., peptic ulcer, gallbladder disease, gastritis, esophagitis, hiatus hernia, (3) chronic lung disease, and (4) neurocirculatory asthenia. A wide variety of psychosomatic and hysterical disorders may also present with anginal-like symptoms. It is important, therefore, not only correctly to diagnose "ischemic" heart disease, but to exclude it with confidence when noncardiac conditions are responsible, and thus avoid iatrogenic cardiac disease. The routine 12 lead electrocardiogram taken with the patient at rest is not sufficiently sensitive always to discriminate cardiac from noncardiac symptoms, as has been emphasized by many investigators. Thus, Wood l observed that 70 per cent of patients with angina pectoris had normal electrocardiograms, while Doyle and co·Consultant CardiologiJt, The Mount Sinai Hospital. --Assistant Professor of Clinical Medicine, Comell Univenity Medical College.

Copyright, 1967, by the American College of Chest Physicians

347

50-59 60-69 70-79 80-89 90-99 100-109 110-119 120-129 130-139 140-149 150-159 160-169 170-179 180-189 190-199 200-209 210-219 220-229

lb.

Weight

20-24

58(56) 56(54) 56(52) 54(50) 52(48) 50(46) 48(44) 48(42) 46(40) 44(38) 42(36) 40(34) 38(32) 36(30) 34(28) *MASTER, A. M.

64(64) 62(60) 60(58) 58(56) 56(52) 54(50) 52(46) 50(44) 48(40) 46(38) 44(34) 42(32) 40(28) 38(26) 36(24)

15-19

56(54) 54(50) 54(50) 52(48) 52(46) 50(44) 48(42) 48(40) 46(38) 46(36) 44(34) 42(32} 42(30) 40(28) 40(26)

30-34

54(52) 54(48) 52(48) 50(46) 50(44) 48(42) 48(40) 46(38) 44(36) 44(34) 42(34) 42(32) 40(30) 38(28) 38(26)

35-39

54(48) 52(46) 50(46) 54(44) 48(42) 46(40) 46(38) 44(38) 44(36) 42(34) 40(32) 40(30) 38(28) 36(26) 36(26)

40-44

52(46) 50(44) 50(44) 48(42) 46(40) 46(38) #{38) 42(36) 42(34) 40(32) 38(32) 38(30) 36(28) 34(26) 34(24)

45-49

50(44) 50(44) 48(42) 46(40) 46(38) 44(38) 42(36) 40(34) 40(32) 38(32) 38(30) 36(28) 34(26) 34(26) 32(24)

50-54

AND ROSENFELD, I.: "The two-step exercise test brought up to date,"

58(56) 56(52) 56(52) 54(50) 54(48) 52(46) 50(44) 50(40) 48(38) 46(36) 46(34) 44(32) 42(30) 42(28) 40(26)

25-29

Age in Years

48(42) 46(40) 44(38) 44(36) 42(36) 40(34) 40(32) 83(32) 36(30) 36(28) 34(28) 32(26) 32(24) 30(22) 28(22)

60-64

65-69

70-74

46(40) 46(38) 44(38) 44(38) 44(36) 42(36) 42(36) 42(34) 40(34) 40(32) 40(32) 38(30) 38(32) 36(30) 36(30) 36(28) 36(28) 34(26) 34(26) 34(26) 32(26) 32(24) 30(24) 30(24) 30(22) 28(22) 28(22) 28(22) 26(20) 26(20) New York I. Med., 61: 1850, 1961.

50(42) 48(42) 46(40) 46(38) 44(38) 42(36) 40(34) 40(32) 38(32) 36(30) 36(28) 34(26) 32(26) 32(24) 30(22)

55-59

TABLE 1 TRIPs PERFORMED IN MASTER DOUBLE (THREE MINUTE) TWO-STEP EXERCISE TEST* MALES AND (FEMALES)

44(36) 42(36) 40(34) 40(32) 38(30) 36(30) 36(28) 34(26) 34(24) 32(24) 30(22) 28(22) 28(20) 26(20) 24( 18)

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Volume H. No.4 April. 1961

EXERCISE ELECTROCARDIOGRAPHY

activity will not normally induce chest discomfort. Frequency of pain also may not be helpful in distinguishing between cardiac and noncardiac causes. For example, angina may occur only once or twice a month, or it may be described as "continuous.'" The duration of the typical anginal episode is usually brief, lasting less than five minutes. However, a third of our patients with noncardiac pain also describe their symptoms as being of such short duration. Cold weather alone as a precipitant of angina (in the absence of significant exertion) has been reported by Davis and RitvoS and by Schott." However, exposure to cold has also been observed to induce pain in noncardiac conditions. Post-prandial angina may occur without exertion, but pain after eating is also common in hiatus hernia, gallblad-

FIGURE

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der disease, cinoma and trointestinal Although

349

esophageal spasm, gastric carfunctional disorders of the gastract. relief of angina by sublingual glyceryl trinitrate constitutes a classic response, one is often confronted with the situation in which the pain is of such brief duration that the efficacy of nitroglycerin cannot really be assessed. Also, one occasionally encounters patients with chest pain of noncardiac origin, who also obtain relief from the glyceryl trinitrate in seconds or minutes (e.g. dorsal arthritis or gallbladder dysfunction). It should also be noted that in 10 per cent of patients with organic heart disease, glyceryl trinitrate does not relieve symptoms. Although angina pectoris is apt to be a chronic disorder, it may appear suddenly, and its course may be characterized by remissions and exacerbations.

See two-step procedure in text.

Diseouc:s of the Chest

MASTER AND ROSENFELD

35°

Also, usually as a result of having reduced his level of physical activity, perhaps unwittingly, or having avoided emotional strain, exposure to cold or other precipitating factors/ a patient may report "disappearance" of his angina. Such "termination" of symptoms may lead the physician erroneously to conclude that the pain was not, after all, due to myocardial ischemia. The diagnosis of ischemic heart disease is further complicated by the fact that the physical findings are often entirely normal. Thus, there may be no enlargement of the heart, no evidence of hypertension, or of valvular or congenital heart disease, no arcus senilis, and an unremarkable biochemical survey. One must never conclude, on the basis of such negative objective observations, including a normal resting ECG, that there is no significant interference of the coronary circulation. In all individuals with chest complaints, however atypical, recourse should be made to the U two-step" exercise 3M les/ • (Fig. I, Table I) (or an equivalent STANDARD

Control

Immediate

stress test). We have found, over the years, that the appearance of "ischemic" changes in the post-exercise electrocardiogram constitutes excellent evidence of the cardiac origin of the symptoms. When this standardized test is completely negative (Fig. 2) it is even better evidence that the symptoms are noncardiac in origin. For all these reasons, we believe that a functional stress test of the heart should be employed yearly in those who are exposed to unusual physical and emotional hazards, for example, the military, policemen and firemen. Also, it is useful in the detection of coronary disease in personnel whose work involves the public safety, for example, train engineers, pilots, bus drivers, etc. Key men in industry and in particular, physicians (who are considered by many to be particularly prone to heart disease) sh 0 u Id also have the test routinely. In fact, all apparently healthy men and women, 35 years of age and over, should have an annual thorough physical examination, a 6 foot xray film of the chest, a biochemical survey, 2-STEP

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IV FIGURE 2: J. C. - Man, 46, who had been a "cardiac cripple" for 20 years. He had been in bed six weeks for two episodes of "coronary occlusion." Each time, he received morphine for severe chest pain. A single (one and one-half minute) two-step test was negative and the next day the regular double (three minute) two-step test was also negative. Obviously, the patient had no heart disease at all. X-ray examination showed a hiatus hernia which accounted for the pain. After reassurance, the patient returned to work and has led a normal life for the past ten years.

Volume ~1, No.4 April, 1967

35 1

EXERCISE ELECTROCARDIOGRAPHY

positive" response. It does, however, seem appropriate that the above-mentioned measures be instituted in view of the prognosis and epidemiologic significance of the positive test in apparently well persons.

a resting electrocardiogram, and if the latter is negative, an exercise electrocardiogram. This is all the more urgent because there is much ischemic heart disease in which the subject is completely asymptomatic.' Finally, the two-step test lends itself to pharmacologic and physiologic study' (Fig. 3). When a positive response is elicited in the absence of supporting clinical evidence, the physician should institute whatever current measures are deemed appropriate to help retard the clinical manifestations of ischemic heart disease, e.g., weight reduction, cessation of cigarette smoking, dietary advice, and drug therapy if indicated in regard to fats, cholesterol, sugar, and a regimen of planned, graded physical exercise, but the avoidance of strenuous exertion and severe emotional strain. The asymptomatic subject should not be alarmed with the information that his two-step test is positive, since it may, in fact, represent a "fa1se-

HISTORIC BACKGROUND OF 1o u EXERCISE TESTINC •

Having stressed the importance of a functional test of the heart, it should be. of interest to relate a short historic background of cardiac functional tests in general and then to present the background of electrocardiographic tests and the two-step test in particular. As early as 1889, and between then and 1964, observations were reported showing that systolic blood pressure and heart rate rose during and directly after muscular work, and then gradually returned to normal. In these early tests, (and in the original two-step procedure) blood pressure and pulse rate determinations made after certain time intervals following measured

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3: H. K. - Man, 63, with a severe anginal syndrome, almost "status anginosus." His pain was completely relieved by iproniazid (Manilid) but his coronary disease was unchanged as indicated by the two-step test. The control tracing showed sinus bradycardia, 37 beats per minute. Following the regular three minute two-step test, dramatic RS-T depressions and inversion of the U-wave appeared. With the cessation of drug therapy, the angina returned.

FIGURE

35 2

Diseases of the Chest

MASTER AND ROSENFELD

exertion were compared with the pre-exercise blood pressure and pulse rate. If these readings were not significantly altered, the individual was considered to have normal myocardial function. These functional tests of the heart usually took the form of some body movement, such as flexing and extending the arms, flexing the trunk, knee-bending, hopping and jumping or stair climbing. Stair climbing was in vogue for many years and is still used. Selig,11 in 1905, was an early exponent of this form of test. Rapport13 directed his patients to climb 45 and 90 steps, each nine inches high; these ascents were made at different speeds. May Wilson 14 employed 25 and 60 steps based on individual varia-

tions, but these did not include age, sex, weight, and height. Magnus-Alsleben 15 and Felberbaum and Finesilver18 also used stair or steps; the latter built two steps each six inches high. In 1901, Brittingham and White1'1 used dumb-bell swinging, from floor to an arm's length overhead. Barringer,18-S1 in a series of articles pu blished between 1915 and 1922, popularized this type of test, and Mannll applied it to the study of patients during convalescence. Barringerl1 em ph asized the reproducibility of these procedures and that the outcome varied but slightly from day to day in the same individual, and in 1922, suggested that normal standards of exercise tolerance of ad uI ts

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4A: Two-step and circulatory efficiency as a function of age. culatory efficiency as a function of weight. FIGURE

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Volume 51, No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

should be determined. Cotton, Rapport, and Lewisu considered evaluating the clinical response on the basis of the total work done. Barringer reported that the use of dumb-bells gave the same results as work with the thighs and legs. May Wilson14 reported that the results of stair-climbing and rope-jumping were similar to those of dumb-bell exercise. For essentially quantitative tests, there is the stationary bicycle, ergostats, and ergometers, where the muscles of the fingers, arm or leg come into play. They have been described by Mendelsohn,14 Graupner,u Benedict and Carpenter," Krogh,17 Cathcart, Wishart and McCall,II and Gillespie, Gibson and Murray." A criticism applicable to such tests was that the same work load was required of all subjects, men and women, young and old, underweight or overweight. Valid standards for normal individuals had not been established, so that results could not be meaningfully assessed. The original two-step procedure, which at first was also interpreted on the basis of the response of the blood pressure and pulse rate to standarized exercise, was devised by Enid Tribe Oppenheimer and Master, at the Cornell University Medical College between 1925 and 1929. 10 After four years of trial, the "two-steps," each nine inches high, were made the basis for the test. It was observed that age, sex, and weight were important factors in work performance efficiency (Fig. 4A, B). The trial tests revealed that with increasing age (Fig. 4A) efficiency of work in foot-pounds per minute was reduced.* Maximum work capacity was less for women than for men. Efficiency declined with increasing weight (Fig. 4B). Hundreds of tests performed on normal persons substantiated this effect of age, sex, and weight. Mathematically formulated tables recorded the number of trips on the two steps according to these variables (Table 1). Height was not found to be a fac-However, old age itself is not a limitation to performance of the two-step test. Our oldest patient was 101 years of age! (Fig. 5).

353

tor when each step was nine inches high. A negative test was one in which the blood pressure and pulse rate returned to approximately resting levels within two minutes after cessation of the standardized exercise. EinthovenaG in 1904 published an electrocardiogram after exercise, but did not suggest that it be employed as a test for heart function. In 1931, Wood, Wolferth and Mary Livesey31 in Philadelphia published a report describing electrocardiographic changes after exercise. Their subjects performed moderate exercise, not the two-step, until chest pain appeared. They felt it was dangerous to have such pain induced, and advised against the use of an exercise test except in really doubtful cases. Although their attitude likely discouraged further use of an electrocardiographic exercise test, they were, nevertheless, the first to propose it. In 1933 and subsequently, Scherf and his colleagues31 wrote on the subject of the post-exercise electrocardiogram. However, they have continued to insist that the amount of exercise performed need not, and in fact, should not, be standardarized. It was their suggestion that one employ that exertion which customarily produces an episode of angina in a given patient. Many types of physical effort have been used by these workers. However, some patients with serious coronary disease never develop symptoms on effort at all, or do so only after certain types of severe exertion such as climbing against the wind or painting a ceiling, or dancing violently or lifting heavy weights; chest pressure may occur only in the morning on awakening, or just as the patient leaves his house, or at the first hole of golf, or with sexual intercourse; some develop chest pain only on emotion; many patients suffer chest pain "spontaneously." Hence, using an exercise of the type that will "ordinarily produce the patient's pain" is not always possible in the physician's office. Katz and Landt in 193511 published a paper suggesting the use of the four lead electrocardiogram after exercise as a func-

354

Diseases of the Chest

MASTER AND ROSENFELD

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FIGURE 5B 5: J. M. - A judge who had no cardiac symptoms and worked as a referee judge until his 100th birthday. At 101, he developed anginal pain and on his 102nd birthday, a coronary occlusion; six months later, a cerebrovascular accident occurred and he died at the age of almost 103 0z. The resting electrocardiogram (see A) at age 100 showed occasional ventricular premature contraction, prolongation of the P-R to 0.28 second, and right bundle branch block. The P-R prolongation had been present a few years. Post-exercise tracings revealed no significant change (B). The ventricular premature contractions persisted. FIGURE

Volume 51, No.4 April, 1967

355

EXERCISE ELECTROCARDIOGRAPHY

tion test of the heart. Unfortunately, the same amount of dumb-bell exercise was used for all, irrespective of age, weight, and sex. This exercise, in our opinion at least, was not standardized and furthermore, represented hard work for a patient with angina. It would be hazardous to some. In 1938, MissalS. wrote that the Master "two-step" was a convenient form of exercise for electrocardiographic interpretation. In 1940, Riseman, Waller and Brownl l used the Master two-step test. However, none of these authors used our tables. They walked the patient until symptoms appeared. This again we considered unstandardized and dangerous. Beginning in 1951, Robb31 and then in 1954, Mattingly, Fancher, Bauer and 3 Robb ? published their observations on a large number of patients using the twostep electrocardiographic test essentially as we performed it.

In 1940, we turned empirically to the routine employment of the electrocardiogram with exactly the same standardized two-step test employed since 1925. In 1940, the visual writing machines had become quite practical.* We published our first paper with this new method in 1941." The patient walked the prescribed number of trips obtained from our table, depending on his age, sex, and weight. Ever since, we have found the electrocardiographic responses more objective and practical than the original blood pressure and pulse rate criteria. PROCEDURE FOR PERFORMING THE

MASTER "TWO-STEP" TEST

The two-step apparatus should be solidly ·In the late 1920's and the early 1930's we had assayed the Siemans-Halske, red ink writing visual electrocardiograph machine at the Cornell Univenity Medical College in New York City. We abandoned it since stray electric current from any nearby electrical equipment would swing the stylus oft' the paper.

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5C: Following the onset of angina at 101 years of age, the resting electrocardiogram was still unchanged (C) but the double two-step test disclosed slight but definite "ischemic" RS-T segment depression in leads II and VI. Myocardial infarction (coronary occlusion) occurred one year later. FIGURE

MASTER AND ROSENFELD

constructed with each of the two steps exactly nine inches (23 cm.) high. A depth of nine to ten inches (23 to 25 cm.) and an approximate width of 18 to 22 inches (46 to 56 cm.) are recommended. The floor should be level so that the apparatus does not move during the test. A thin rubber matting on the top of the steps gives added security (Fig. 1). Proper performance of the procedure requires the existence of essentially basal conditions in a comfortably cool room. Routine medications and smoking should be deferred on the test day, and every effort made to insure a restful night's sleep. A tranquil and comfortable atmosphere, undisturbed by extraneous stimuli, and at least a ten-minute rest period prior to the exercise, are important. The patient ideally should omit breakfast, but may eat lightly. No medication should be taken the morning of the test. Digitalis, quinidine, procainamide, diuretics and thyroid may affect the results, and should be omitted for appropriate periods prior to testing. A careful clinical evaluation of the patient must always be made just prior to exercise to rule out the existence of acute illness or impending infarction. The resting electrocardiogram taken immediately before the two-step test must either be normal, or if abnormal, stable. Prior to performing the test, the procedure should be explained in detail to the patient, with particular emphasis on the instruction to stop immediately when he experiences any chest, arm, or neck pain, discomfort, or abnormal sensation during the walk. The age, sex, and weight of each patient determine the number of trips to be performed, as indicated on the published "twostep" chart (Table 1). During the exercise, the limb electrodes are left in place with the lead wires attached. The chest electrode remains in the V 5 position. Holding the patient cable, the subject ascends to the top of the "two-step" and walks down the other side. This is counted as one trip. He then turns around and retraces his steps, until the full number of trips is completed in

Diseases of the Chest

three minutes. (He should always tum toward the technician; since, in so doing, he reverses the direction of turn at the end of each trip and "unwinds" himself, avoiding becoming dizzy. The turning also provides a momentary rest. Thus, there is a decided difference between walking steadily up 72 steps, for example, and performing 36 trips on the "two-step" apparatus and pausing after each crossing). The rate of ascent and descent should be controlled by the sweep second hand of a time-piece. A variation of a few seconds in the duration of the test is permissible. At the completion of the exercise, the patient lies down immediately, and is encouraged to relax fully. The lead wire cable is instantly inserted into the machine. Electrodes and connections should be quickly checked to ensure that they have not been disturbed. Tracings are recorded immediately after exercise, in two minutes, and finally, in six minutes, or until the record returns to the resting or control appearance. Leads taken are V 5' V 4' V 6' V 3' II, usually in that order. Occasionally, immediately after exercise, the stylus of the electrocardiograph may wander, especially if respiration is rapid or deep. The RS-T segment may thus appear either artifactiously elevated or depressed. Correct interpretation and measurement of the RS-T segment deviations can only be made in the presence of a baseline that has remained level for at least three consecutive beats. If the patient momentarily suspends respiration, the baseline is much less apt to wander. The P-Q or P-R interval (and not the T -P interval) is the reference point with which the level of the RS-T segment is compared. MONITORING THE TWO-STEP TEST

The development of electronic devices that permit the radio transmission of electrophysiologic data from a distance··· has stimulated interest in monitoring the twostep test during its actual performance. Several technics for doing so with the patient remaining attached to the electrocardiograph machine have also been described.

Volume SI, No.4 April. 1967

357

EXERCISE ELECTROCARDIOGRAPHY

Our experience in detail with the "monitored two-step test," using several radiotelemetric devices, as well as a direct hookup system has been reported in detail.".41 We have not found radiotelemetric devices necessary for recording the two-step test, since this can easily be done by a direct hook-up or "hard-wire" system requiring no electronic equipment. The subject remains connected to the ordinary electrocardiograph machine by the patient-cable. The ECG is recorded while the patient is actually traversing the two-step apparatus. The key to obtaining a successful tracing lies in the selection of the electrode and the technic of its application. We use a commercially available product, resembling a band-aid, which is one and one-half by one and one-half inches, has a steel mesh with a small reservoir electrode for the contact jelly, and is disposable (Fig. 1 and 6). This cup mesh electrode enclosed in the band-aid is three-eighths inch in diameter. Adapters connect to a snap-fastener on the electrode and to the lead wires of the electrocardiographic machine. Electrodes are placed in the lead V G and V 5R positions, and the record is taken with the lead switch of the electrocardiograph in the lead I position. As in radiotelemetry, the result is a bipolar lead very similar to lead V 5' but not identical to any of the 12 leads of the routine EeG, and is characterized by augmented amplitude of all its deflections.' More recently, we have been able to re-

A

FIGURE

6A

cord a conventional unipolar chest lead during exercise, modified after the technique of Mason, Likar and Rose" (Fig. 1). Electrodes are placed at both infraclavicular areas, above the left iliac crest and on the right leg. The exploring electrode is placed in the V.-V6 position, and the lead selector switch is in the V position.4f Monitoring the two-step test by either radiotelemetry or direct connection consumes much recording paper, usually requires two people to perform it, and necessitates a great deal of marking, cutting, and mounting if a permanent record is desired. However, the ECG may be visualized on an oscilloscope screen. It is to be emphasized that the erect position of the subject during monitoring may introduce some unpredictable variations in the monitored lead not present in the recumbent position, such as altered configuration and amplitude of the QRS complex, RS-T segment deviations above and below the baseline, and variations in the T-wave amplitude and direction. Such variations occur among the apparently healthy as well as in patients with ischemic heart disease, and appear to be independent of hyperventilation of respiratory maneuvers. In short, monitoring the two-step test by any of the currently used techniques represents a variation of electrocardiography which requires study of statistically significant numbers of normal subjects before and valid conclusions may be drawn from its results.

B

FIGURE

6B

6: Picture of electrodes: In the central ~.. diameter mesh, the electrode jelly is placed (see A), Band-aid type of adhesive keeps the electrode tight against the skin of the chest. The back of the disposable electrode has a clip on which the lead cable is snapped (B). FIGURE

Diseases of the Chest

MASTER AND ROSENFELD

We have now monitored in excess of 800 two-step tests. We have found this modification of great interest, especially from the research point of view, but in comparison to some investigators, neither we, Kaltenbach nor Takahashi et al believe that it results in a greater diagnostic yieId than does the post-exercise tracing.' RESULTS OF THE TWO-STEP TEST

Pain In our experience, the over-all incidence of chest pressure or pain produced by the two-step test among those with definite organic disease, is about 20 per cent. About one-fourth of these patients with angina pectoris experience the pressure during the test and stop and the remainder become aware of the chest symptom when they lie down. If necessary, relief can be obtained when the patient sits up. Hence in only about 5 per cent of cases of angina pectoris does the patient actually stop the test because of pain and in 15 per cent he develops the pain on lying down. When pain or pressure appear in the course of the two-step test, the ECG is nearly always positive. In the rare instance when this was not the case, we found that the patient stopped on the very first awareness of the onset of pain. It was thus an "impending angina" rather than the actual

pain or pressure. On repetition of the test, an hour later or the next morning, if the patient climbed but a few more trips and certainly if he completed the required number, the test was positive. It would appear that the brain may be "alerted" actually before coronary "spasm" or full myocardial ischemia occur and if the patient ceases to exercise then and there, the attack is aborted and no ECG changes appear. The therapeutic implication is obvious. The patient is alerted to stop any activity that will precipitate pain or pressure immediately, rest or take a nitroglycerin tablet, then proceed further. Safety We have supervised many thousands of two-step tests since the period 1925-29 without significant adverse reactions attributable to the procedure. Critical analysis of a few reports of myocardial infarction following this test reveal circumstances which clearly contraindicated the use of any effort. For example, Grossman and Grossman48 wrote on the subject "Myocardial Infarction Precipitated by Master Two-Step Test." The patient in question had been sick most of the night prior to the test. Nitroglycerin had not relieved the pain and morphine had been required. The resting electrocardiogram was definitely abnormal and we suspect the patient was in

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FIGUllE 7: M. N. - Man, 78, who sustained a coronary occlusion 34 years ago. Since then, he has experienced severe anginal pain. The resting electrocardiogram has been stable for years and shows Q-waves In II, III, aVF and V"" as well as depressions (See A). The monitored single two-step test (one and one-half minute) revealed progressive changes in the ST segment and the "ischemic" pattern in the last few trips (B).

Volume ~1, No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

the throes of an impending infarction prior to the test. Nevertheless, certain authorsconstantly refer to this as an example of the "danger" of the two-step test. It should be clearly understood that in cases of an impending coronary occlusion, or where a patient has had a recent heart attack, the test is contraindicated. The principles of simple, sound medical judgment are not less appropriate in this area than in all medicine, and their simple application has, in

359

our extensive experience, resulted in an excellent safety record. As to quantitative correlation of the "ischemic" RS-T segment depression with the extent of the disease, we have stated on many occasionslO.Jl that in general there was a fairly good association. Robb and Marks's proved this statistically in 1964. However, there are exceptions. We have patients who disclose depressions of 2 mm or more and yet continue to carry on a

7C The regular post-exercise electrocardiogram disclosed increased "ischemic" ST changes (C). Auricular premature contractions were seen both in the resting VI and monitored tracings. In spite of the dramatic "ischemic" depressions after the exercise test and the severity of the anginal syndrome, the patient has led a good but restricted life for 34 years. He supervises a business which is distributed over the globe; he travels to his factories by air. This case again illustrates that, in spite of the general role that ST de~ression and coronary disease have a quantitative correlation, dramatic depressions frequently are compatible with long life. FIGURE

Diseases of the Chest

MASTER AND ROSENFELD

avoid undue mental and emotional strain. Even patients with severe angina are directed to walk, stop a little short of where they expect to develop, rest a moment, and then proceed. This they are to repeat again and again. Or another procedure is the use of nitroglycerin at the start of the walk or to proceed at a pace that will not bring on pain, to rest occasionally, to window shop ocasionally. Our patients often walk for miles. On rare occasions we have permitted our patients with angina to perform what at first might be considered strenuous exertion but these were persons who had been trained in the particular activity and the acquired skill had made it an "easy" task. Thus, we have allowed some men to bowl, compete in amateur golf tournaments and even to ski. These sports were accustomed

good worthwhile existence both in their business and social lives for many years (Fig. 7). Of course, they limit themselves sensibly. Again, we have seen a depression of only Y2 mm (Fig. 8 and 9) become greater and greater as time progressed, but still, as yet, we call any RS-T depression of Y2 mm or less a normal response and will continue to do this since it appears that this patient, in general, is normal for a good long time. It should not be concluded because we are against a strenuous exercise test, that therapeutic-wise we do not advocate physical activity for our patients with angina. We encourage it very much. For almost two score years,II we have advised physical activity for the patient with angina and for the patient who has recovered from a myocardial infarction. He is encouraged to work, swim, golf, drive a car provided he

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8: L. H. - Man, 67, physician, with an anginal syndrome. The resting electrocardiogram was negative (see A). The monitored two-step test reveals benign "j" depression on the third trip, which became abnormal on the 17th trip and still more so on the 32nd trip (B). The post-exercise (C) test disclosed "ischemic" ST depressions of only 0.5 mm in the two minute V. tracing and at six minutes in lead II. The patient developed myocardial infarction one year later. The depth of ST depression correlates with the severity of the coronary disease only in a general way, but occasionally an "ischemic" ST depression of only 0.5 mm is significant. FlOURE

Volume ~1. No.4 April. 1967

EXERCISE ELECTROCARDIOGRAPHY

ones, caused no apprehension or discomfort; they were pleasurable and of no moment to these particular people. The skier,

for example, an Austrian, had been a world champion, but he had developed an anginal syndrome.

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9: G. G. - Man, 51, with a six week story of substernal pressure on exertion. The resting electrocardiogram was negative (see A). At two minutes, the double two-step test revealed only 0.5 mm "ischemic" ST depression in VI (B), but three months later, the patient experienced a severe pain; the electrocardiogram (C) now disclosed monophasic curves characteristic of acute inferior infarction. The patient died five minutes later. The degree of ST depression correlates with the severity of the coronary disease only in a general way, but occasionally an "ischemic" ST depression of only 0.5 mm is significant. FIGURE

Diseases of

MASTER AND ROSENFELD CRITERIA OF A POSITIVE TWO-STEP TEST

Following our use of the electrocardiogram in 1940-41 after standardized exercise, we considered any depression of the RS-T segment as possibly significant, but emphasized repeatedly that th~ changes could stem either from organic disease of the coronary arteries or from functional causes, and the final decision was dependent on the entire clinical picture. In 1950, Paul Wood, McGregor, Magidson and Whittaker1 in England stressed the importance of the configuration of the depressed RS-T segment, and coined the term "ischemic" and "junctional" to describe the basic variations observed. "Ischemic" characterized the flat, horizontal, or frankly sagging RS-T segment, in contradistinction to the

the Chest

depressions of the "j" or "junctional" portion alone. Evans and McRae" in Britain in 1952, Malhotra and Pathania" in India in 1954, Myers and Talmers" in this country in 1955, FeuiltaultST in 1956, Manning" in 1957 (both of these in Canada), Robb, Marks and Mattingly" in 1956, Mattingly, Robb and Marks" in 1957, Lepeschkin and Surawicz11 in 1958, all reported on the importance of distinguishing the ischemic RST depressions from the "junctional" types. Robb and his associates, then Mattingly and his colleagues, basing their studies on extensive clinical experience and follow-up for years with hundred of persons, gave statistical validity to the significance of the ischemic RS-T depression. According to

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baseline quickly without tendency to be horizontal in type.

Volume 51, No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

these authors, any depression of the RS-T interval characterized by an initial horizontal course of at least 0.08 sec. to 0.12 sec. or a definite sag, was abnormal. On the other hand, if the depression was solely at the "j" or junction of the QRS with the RS-T segment, it was of intermediate or little significance (Fig. 10 and 11). In this "junctional" type of depression, the RS-T segment quickly rose to the isoelectric baseline. We, too,'· re-emphasized the importance of distinguishing the "ischemic" RST depression from the "junctional" types.

"".,,.1,11

Further experience with the two-step test has resulted in our own refinement of the criteria for its interpretation. However, the depressed RS-T segment spells out the positive test. While we concur that an "ischemic~~ RS-T segment depression of more than 12 mm should be considered an abnormal response, we do not agree that a junctional depression is invariably benign (Fig. 12). Thus, in one series of 281 patients with "junctional" or "j" RS-T segment depressions after exercise, 92 (32.7 per cent) were judged to have unequivocal coronary disease.' These "significant junctionals" differ from their benign counterparts in that (a) they do not return as promptly to the baseline, but instead, assume a more gradual or slow ascent to iso-

FIGUIlE

12:

electricity, and (b) the extent of depression is usually greater (Fig. 3, two minute II and Fig. 9B, "immediate" V 4) • These differences between the significant and insignificant "junctional" depressions can almost always be determined visually. When borderline responses occur, two additional techniques of analysis may be employed to aid in their interpretation. The first is determination of the QX/QT interval as described by Lepeschkin and Surawicz,1l where "x" is the point at which the ascending RS-T segment intersects the baseline (Fig. 12). A value of 50 per cent or more reflects prolongation of the QX, that is, delay in return to the baseline. The second technique is measurement of the QT interval (corrected for rate), and expr~d as the QT ratio. This can be quickly calculated by means of a small ruler designed by Dr. William Welsh.* A value in excess of 1.07 may be abnormal. Both these parameters are of doubtful significance in the young adult under 25 years of age and also when heart rates are rapid, e.g., greater than 110 beats per minute. Administration of quinidine, digitalis, or thyroid hormone as well as electrolyte imbalance may also render these criteria invalid.

I.

*"QT Calculator" available from Bowen and Company, Bethesda, Md.

Modified from Lepeschkin, E. and Surawicz, B.: New England ]. Med., 258: 511, 1958.

Diseases of the Chest

MASTER AND ROSENFELD

When both QXjQT and QT ratios were abnormal in 110 "junctional" or "arc-like" depressions found in patients with coronary heart disease, the correct diagnosis was made in 102. If only one parameter was abnormal, the results could not be established. The foregoing criteria was recently evaluated in 800 individuals with normal or pre-exercise ECGs.a The average duration of follow-up in which the final diagnosis, with respect to the presence or absence of ischemic heart disease was made, was approximately nine years. Three hundred and thirty-two patients had a negative double two-step test and of these, 97 per cent were judged clinically to be free of ischemic heart disease. The remaining ,I

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3 per cent (ten patients) did have ischemic heart disease or subsequently developed it despite the negative test ("false-negative"). Of 158 cases with "ischemic" ST segment depression and abnormal QXjQT and QT ratios only 3.8 per cent were judged clinically to be free of ischemic heart disease ("false-positive" ) . The validity of the QX/QT and QT ratio has been questioned.II_"M Reasons for discrepancy are not clear, but may include the following: (a) errors in accuracy in measurement of the electrocardiographic parameters involved, (b) errors in validity of the clinical status of the patients reported (transient out-patient clinic populations without adequate follow-up," and insurance applicants with lack of candor concerning

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13: S. S. - Man, 69, with angina pectoris, previous coronary occlusion. Right bundle branch block present (see A). In two-step test (B) RS-T elevations appeared in "immediate" tracing V,.V.o (A premature contraction was present in V.).

FIGURE

Volume 51, No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

symptoms'I), (C) application of these criteria to rapid heart rates, or (d) to'-su~ jects under 25 years of age. OTHER POSITIVE POST-EXERCISE CHANGES

While the great majority of positive tests are manifested by abnormal RS-T segment depressions, one may observe other isolated abnormalities with similar diagnostic significance. These include RS-T segment elevation, complete reversal of direction of T-wave, inversion of the U waves, alterations in QRS configuration (appearance of a Q-wave) and disturbances in rhythm. However, these are practically always accompanied by an "ischemic" RS-T segment depression so that this still remains the criterion of a positive two-step test. Elevation or further elevation of the RST segment usually occurs when some elevation was already present in the control trac-

FIGURE

14A

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FIGURE

14C

ing and is observed most commonly in associat1on: With" infarct patterns in the control record (Fig. 13). Significant T-wave inversions almost always accompany depressed RS-T segments (Fig. 12 and 14). When a patient with known ischemic heart disease and a stable but abnormal control tracing performs the two-step test, frankly inverted T waves may become upright, (at least 1.5 mm) and this constitutes an abnormal response. Distinct inversion of the tt u" wave is almost invariably observed in association with abnormal RS-T depression. Very rarely indeed isolated inversion of the "u" wave without any accompanying RS-T deviation may be observed in patients with angina (Fig. 3). Alterations in QRS configuration in patients with ischemic heart disease may rarely be seen after the two-step test. These in-

14: M. W. - Man, 67, with anginal syndrome, enlarged heart and diabetes. The resting electrocardiogram is essentially negative (see A). The monitored electrocardiogram shows gradual progression from a "j:' or arc-like depression at the 15th trip to "ischemic" depression at the 20th trip, and still deeper depreSSIon by the 34th to 36th trips. (B). The regular post-exercise tracing revealed "ischemic" depressions in V &-8 and transitory T -wave invenions in V 2-j (C). Although this type of definite T -wave inversion is considered abnormal, it is always observed with "ischemic" ST depression.

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15: S. F. - Man, 68, physician, with long-standing hypertensive coronary disease, enlarged heart and angina pectoris. The resting electrocardiogram showed the pattern of left ventricular hypertrophy, i.e., distinct left axis deviation, ST depressions and T inversions (see A). It remained stable for years. In the monitored tracing (B) "j" (junctional) ST changes appeared which increased as the exercise continued. Ventricular premature contractions were present at the 7th trip; they formed bigeminy at the 12th and were multifocal at the 21st. Post-exercise electrocardiogram revealed no arrhythmia but there were transitory Q-waves in VI,. and "ischemic", sagging ST depressions in V 4. The tracings had not returned to the control state- 10 minutes after exercise (C).

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Volume 51, No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

clude the transient appearance of Q waves (Fig. 15), left bundle branch block, and other intraventricular block patterns. All such changes probably constitute a positive test, but no valid statistics are available on this uncommon phenomenon. The transient appearance of right bundle branch block represents an "equivocal" response unless accompanied by diagnostic RS-T segment deviations. Disturbances of Rhythm: It is very unusual for a positive test to be manifested solely by an arrhythmia, although virtually every variation in rhythm may be seen during and/or after the two-step test (Fig. 5, 7, 13, 15, 16). For example, we have just reviewed 600 patients performing the two-step test; 170 (28 per cent) manifested I

FIGURE

16A

FIGURE

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some type of arrhythmia either at rest, during, or post-exercise. The greatest number of arrhythmias occurred among men with "organic" heart disease (38 per cent) and also among women with heart disease (21 per cent), while among subjects with "functional" trouble, men and women, the incidence was 16 and 19 per cent respectively. While every type of arrhythmia may be observed during or after exercise in coronary disease, "functional" cases showed only unifocal ventricular or atrial premature contractions. Of 27 "organic" men in whom an arrhythmia was present pre-exercise, this was worsened by exercise in 14 instances, but improved or disappeared in 13 cases. In the "functional" group, arrhythmias present

16: C. B. - Man, 50, with previous coronary occlusion and severe angina pectoris (see A). Old anterior infarction evident in resting electrocardiogram. Double two-step test (B) "immediate" tracing showed 2:1 A-V block in VI, and 3:2 A-V in V.. One atrial premature contraction was present in V.. Note dramatic "ischemic" ST depressions in polt-exercise record which required 20 minutes to return to normal. The patient died six months later during strenuous play in a golf tournament.

FIGUD

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17: J. L. - A young physician who developed a myocardial infarction at 31 (see A). He made a complete recovery. The resting tracing (A) disclosed Q-waves in II, III, aVF, residue of the inferior infarction. The monitored two-step test (B) and the regular post-exercise electrocardiogram (e) were negative. Six yean after the attack, the patient is asymptomatic and works around the clock 81 an oculist.

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MASTER AND ROSENFELD

Diseases of

the Chest

WITH ABNORMAL CoNTROL TRACINGS

has occurred" (Fig. 17). This is of particular interest because years ago when the concept of recovery after myocardial infarction was not widely accepted, such negative tests were thought to represent "falsenegative" responses, and these data were used as evidence of the diagnostic limitation of the two-step test. A negative twostep test in patients who become asymptomatic after a myocardial infarction suggests effective collateralization in the area of the occluded vessels. Whereas the appearance of an ischemic ST segment or a further deepening of an underlying ischemic depression in the control EeG suggests that active ischemia can still be induced by moderate effort and that the coronary circulation remains impaired. Furthermore, after a bona fide second transmural infarction with a stabilizing ECG, the two-step is almost always positive. Survival after a third bona fide transmural infarction is very unusual, if at all.

For many years we had advised the use of the two-step test in people with normal control records. However, the two-step procedure may be performed with equal safety when the control tracing is abnormal, provided the physician makes absolutely certain that the subject to be examined is stable, both clinically and electrocardiographically. The abnormal resting tracing is therefore no limitation to the two-step test. If one excludes individuals with recent changes in the chest pain pattern, or those with significant fluctuations of the EeG, the moderate physiologic type and amount of stress demanded by the twostep test can be safely performed in known cardiacs. The most important application of the two-step test in the group of patients with known heart disease is the evaluation of cardiac function after myocardial infarction. Prejudices concerning the rehabilitation of patients with myocardial infarction are disappearing. First, an apparently complete recovery can and often does take place after coronary occlusion, and a negative double two-step test suggests that this

Vs. RANDOM EXERCISE Over the years, the importance of standardization of exercise has been stressed by us and others;67,t1,.. (Fig. 14, 18-20) and rejected by others. al Pr-oponents of a standardized procedure have emphasized reproducibility and comparability of results among investigators the world over and moreover if a healthy man is asked to perform strenuous exercise, ischemic RS-T depressions may appear in the electrocardiogram...... Setting a reasonable upper limit on the amount of exercise prevents potentially dangerous over-exertion, yet still ensures an adequate amount of stress to render a negative response meaningful. Critics of standardization have maintained that only the specific type and degree ofexertion necessary to reproduce symptoms is required, and that in asymptomatic subjects, stress should be geared to individual physical fitness rather than set amounts of exercise according to age, sex, and weight. More recently, it has been suggested that the standardization of exercise, as prescribed in the two-step table is not optimal. Thus, Sheffield, Holt and Reeves,11 while

at rest also manifested no clear cut pattern after exercise, disappearing, improving, or worsening with the same frequency. Our observations with respect to arrhythmias may be summarized as follows: disturbances of rhythm occur more often in "organic" than in "functional" cases. In the latter, unifocal, non-consecutive ventricular premature contractions or single atrial or nodal premature contractions may be observed. However, among patients with heart disease, multifocal and/or consecutive VPC's, paroxysmal ventricular tachycar. dia, complete heart block, or partial heart block with dropped beats (Fig. 16), atrial tachycardia, fibrillation and flutter may be observed. All but the premature beats are indeed very infrequent. We have not witnessed a single sustained or permanent disturbance of rhythm following the two-step test. RESPONSE TO EXERCISE IN PATIENTS

STANDARDIZED

VolUllle 51, No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

maintaining that "standardization of an exercise electrocardiographic test for myocardial ischemia is desirable," advocate a "graded" exercise test, in which an amount of stress is perfonned which will induce 85 per cent of the maximal age-predicted heart rate. 11* On the basis of results in 216 subjects (follow-up period not stated), these investigators claim that such grading of *This predicted heart rate, however, was calculated in apparently healthy subjects some 30 yean ago, and may be excessive for patients with cardiac disease.

FIGURE

19A

FIGURE

19B

FIGURE

19C

37 1

exercise results in greater sensitivity in the diagnosis of ischemic heart disease than does the conventional two-step test. Use of the graded exercise test requires some type of monitoring device, since the heart rate to be achieved is determined during exercise, and not after its completion. At the present time, we feel that this fonn of exercise, going up and down a 12-inch step, may be dangerous for the anginal patient, in the hands of the unskilled.

......\ J. 19: J. G. - Man, 54, with previous myocardial infarction and a severe anginal syndrome. Old anterior infarction, (rS in V1-1) is evident in the resting electrocardiogram (see A). The monitored test (B) revealed an abnormal change in the ST segment only at the 24th trip. It then progressed until the 35th trip when the test was stopped because of pain. In the regular post-exercise a transitory QS appeared in VI and dramatic depressions in VI-I (C). This case also emphasizes the need for standardization, that is, performing the entire number of trips standardized for age, sex, and weight, all considered in the published tables.

FIGURE

37 2

MASTER AND ROSENFELD

Diseases of the Chest

20: J. F. - Man, 36, with classic angina pectoris. The resting electrocardiogram was normal (see A). The monitored two-step test at tint showed "j" (junctional) depressions; these became more pronounced as the exercise continued until they became "Ischemic" at the very last trip, the 42nd (B). The regular post-exercise tracing showed "ischemic" depressions, maximum at two minutes in VI (C). The monitored test showed the necessity of performing the full number of trips indicated in the published tables, since the tracing became "ischemic" only at the very end of the exercise. In other words, it is essential that exercise tests be standardized for age, sex, and weight. FIGURE

Volume 51, No.4 April, 1967

373

EXERCISE ELECTROCARDIOGRAPHY

step" imposed "an equal energy demand in-':patients· of .different age and weight." The treadmill is much bulkier and costlier than the simple two-step apparatus. Also some older persons, particularly those with arthritis or neuromuscular disorders of the back, may find it difficult to maintain the tilt of the body required to walk along the inclined treadmill. Whether the "graded" exercise test of Sheffield, Holt and Reeves" and the treadmill procedure of Rowell, Taylor, Simonson and Carlson" possess any significant advantage over the two-step test will be determined with the passage of time and the accumulation of more statistically significant data. Nevertheless, it is also to be noted that the maximal age-predicted heart rates, used both by Rowell and Sheffield, and their respective co-workers, are derived

Rowell, Taylor, Simonson and Carlson," after evaluating 14 men subjects,-t6itcltlde:that the "physiological load imposed by the double Master two-step test-fails to provide a physiologically equivalent work load for individuals differing in body weight." These investigators suggest the use of a treadmill to effect the same oxygen consumption per kilogram for all individuals of the same sex. The validity of these conclusions is open to question since the data are derived from a study of only 14 persons whose age range was only 12 to 27, with four subjects actually 12 to 14 years. The findings of these authors are not only inconsistent with our own, but with those of Ford and Hellerstein" who studied the physiologic work load in a large number of persons in the pertinent coronary age group and found that the "Master two-

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21: A. L. - Man, 40, with neurocirculatory asthenia. The resting electrocardiogram was entirely normal (see A). The monitored two-step test (B) first showed slight "j" depression at the 12th trip, which became significant on the last few trips of exercise.

FIGURE

Diseases of the Chest

MASTER AND ROSENFELD

374

from a single study, done in 1938. Again, Robinson'l dealt with physical fitness in healthy boys and men not in the discovery of ischemic heart disease. The heart rate attained in the two-step test, as revealed by our monitored techniques, is more than adequate, as confirmed by the fact that positive tests are seen as often when the maximum rate is 110 or less, as when the rate is 150 to 170 beats per minute. Certain investigators have recently reported the results of exercising subjects well beyond the upper limits of the two-step table. Thus, Doan, Peterson, Blackman and Bruce'14 have continued treadmill exercise of subjects to the point of virtual exhaustion, and suggest that electrocardiographic abnormalities occurring after such maximal stress may be of prognostic significance even in apparently healthy volunteers. Whether or not these findings will, in fact, have the expected prognostic implications will de-

pend on the results of long-term follow-up, and the incidence of morbidity and mortality from coronary heart disease in those subjects with an "abnormal" response after maximal exercise. While very strenuous exertion may lend itself to epidemiologic surveys of vigorous, young adults, its use in clinical medicine is limited and may be hazardous. Kattus and MacAlpin13 suggest the presence of an adaptive mechanism in angina pectoris, manifested by the disappearance or decrease in magnitude of RS-T depression occurring during exercise, if the stress is continued despite pain. While of great physiologic interest, widespread application of such tests to "walk through" an attack of angina pectoris are not advised by the authors. Incidentally, an ability to adapt to exercise may be an outgrowth of confidence gained by the anginal patient as he repeats tests from time to time ("the professional two-stepper").

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21C: The post-exercise electrocardiogram also revealed "ischemic" depression (see "immediate" two minute lead II and 2 minute VI.'). This is an illustration of a "false-positive" test in an extremely anxious penon.

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Volume ~1. No.4 April, 1967

EXERCISE ELECTROCARDIOGRAPHY

CONFIRMATION OF THE

"TWO-STEP" TEST

The great weight of evidence supports the contention that the two-step test is extremely valuable in the diagnosis of coronary disease and far outweighs the criticism of the procedure. A recent paper by the authorsl summarized our experience with a large group of patients. The results of this long follow-up study confirmed the accuracy and usefulness of this test in detecting coronary disease. With few exceptions, those patients referred for an evaluation of chest pain and whose two-step tests were nonnal remained in good health over a long period of observation, whereas those whose two-step tests disclosed "ischemic" RS-T segments had or soon developed definite evidence of significant coronary disease. Manv others have confinned the value of the ~o-step test in evaluating chest pain. Robb, Marks and Mattingly" studied 836 military personnel and 379 applicants for insurance policies in whom there was a suspicion of coronary artery disease, usually because of a history of chest pain. Significantly, they found that those patients with "ischemic" changes following the twostep exercise test had a subsequent cardiac death rate almost three times greater than the group with negative results. In 1959, Franco, Gerl, and Murphy" published the results of their study of personnel at the Consolidated Edison Company of New York. Their reports summarized ten years of experience with the Master two-step to evaluate cardiac function in 544 employees. Only 6 (1.5 per cent) of 408 workers with a negative result subsequently developed myocardial infarction, whereas 20 (15 per cent) of the 136 people with a positive result experienced some fonn of infarction. In 1960 and 1961, Gubner·"'" published a critique of the two-step based on his own considerable experience in the insurance industry and an extensive review of the existing literature on the subject. In his opinion, the "Master double two-step exercise test

375

serves conveniently for the detection of coronary insufficiency, and for objective evaluation of chest pain, particularly since resting electrocardiograms are normal in approximately half of patients with angina pectoris." Furthermore, Gubner noted that for persons with positive tests "death rates and subsequent attacks of myocardial infarction are as high as eight to ten times that in persons with normal responses." Robb and Marks, in 1964, published their most recent observations of the use of the two-step test in detecting latent coronary artery disease. 11 Those patients who developed ischemic RS-T depr~ions following a two-step test had a mortality rate over four times that of the group with negative responses. Furthennore, the death rate from coronary disease (excluding all other causes of death) was seven times greater than that seen in the negative group. It was their belief that any ischemic S-T segment depression was "valid evidence of coronary insufficiency due usually to atherosclerosis", and that a negative test, "excludes, for practical purposes, the presence of latent coronary disease." Hellerstein, Prozan, Liebow, Doan and Henderson in 1961 ,81 after nine years of performance of the test in 1,700 patients "without untoward incidence" wrote, "The response of the two-step test, when related to other medical, vocational, social and psychiatric data, has been valuable" .... They again stated, "The two-step test is a valuable test of cardiac function" .... and "has proved to be of value as an objective measure of circulatory fitness." Johnson," at the U.S. Air Force School of Aerospace Medicine found that "the Master two-step test is an excellent clinical procedure which has proved its value" .... Further he felt that the recognition of asymptomatic coronary disease in apparently healthy fliers and candidates was of "critical importance." In view of all the reports which we have briefly mentioned, it is apparent that the two-step test has usefulness and validity in

Diseases of the Chest

MASTER AND ROSENFELD establishing the presence or absence of significant coronary artery disease. DIAGNOSTIC LIMrrATIONS OF THE TWO-STEP TEST The frequency of "false-positive" responses, i.e., an abnormal two-step test in apparently healthy persons, is difficult to assess. Insurance statistics have shown that even in such asymptomatic individuals, an abnormal response to exercise has longterm prognostic implications. Real "falsepositives" no doubt occur, but the continuing refinement of a criteria for interpretation of the test has reduced their incidence to the 5 per cent range or less. Persons most likely to manifest such "false-positive" results include the young, the very nervous or frankly psychoneurotic patient, especially a woman, the nervous menopausal woman, individuals with neurocirculatory asthenia (Fig. 21), and those prone to recurrent paroxysmal tachycardia. A common problem in clinical, industrial and insurance medicine is the evaluation of RBBB patterns in apparently healthy individuals. In our experience, patients who

have undeniable clinical angina with such "uncomplicated" RBBB patterns rarely have negative responses; they almost always depress the RS-T segments either in the left precordial leads (V 4-V6) or in the right precordial leads (V 3R-V 3) (Fig. 5). In the former instances, the test may be interpreted as abnormal. However, RS-T depression limited to the right precordial leads may be observed in otherwise healthy individuals with RBBB. Long-term follow-up studies and the accumulation of a large body of data may clarify this problem in the future. At the present time, it remains a diagnostic limitation of the two-step test. The presence of LBBB in the ECG bespeaks underlying myocardial involvement. This may be either on the basis of primary coronary artery disease with anatomic involvement of the left bundle or it may reflect an advanced stage of left ventricular hypertrophy such as occurs in long-standing arterial hypertension. Because of the aberration of conduction, and the distortion of the normal time relationships between depolarization and repolarization, RS-T segment and T-wave abnormalities

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FIGURE 22: F. E. - Man, 31, who developed rheumatic pancarditis at A,nnapolis during World War II. The mitral and aOrlic valves were involved. He made an excellent functional recovery and has played lacrosse since. A double two-step test has been negative, repeatedly (A). The teleroentgenogram revealed normal hean and lungs (B).

Volume ~I. No.4 April. 1967

EXERCISE ELECTROCARDIOGRAPHY

cardial oxygenation when the patient exercises, -that- is, performs the two-step test. The two-step test is virtually impossible to interpret in the presence of digitalis,1f since this drug causes depression of the RST segment and T -wave changes. Greatly increased heart rates resulting from strenuous exercise accentuate such abnormalities and almost always produce a positive response, even in apparently normal persons. This problem is of importance in the evaluation of patients who are receiving digitalis prophylactically, as, for example, in recurrent supraventricular tachycardia. If a twostep test is to be performed in these cases, digitalis must be withheld for an appropriate period of time, depending on the specific digitalis preparation being used. The increasing application of coronary arteriography has resulted in studies which attempt to correlate results of the two-step test with anatomic changes visualized in the coronary circulation. Such correlation must be interpreted with caution for several reasons. First, the significance of the radiographic findings is not yet clear because of the relative recency of the technique. One does not know what constitutes

are extremely difficult to assess even in the control record. However, from timetetime in individuals with angina pectoris, exercise will induce further marked "ischemic" depression of the ST segments. On the other hand, when exercise results in virtually no change in the already abnormal ST-T configuration, the presence of active ischemia is less likely. The two-step test may be useful in the assessment of patients with chronic rheumatic valvular" (Fig. 22-24) and congenital heart disease (Fig. 25). Here, the test reflects the degree of myocardial perfusion rather than coronary artery disease or patency. Thus, given a patient with mitral or aortic valve disease or pulmonary hypertension due to any cause, a positive twostep test indicates that the hemodynamic or structural abnormality is adversely affecting coronary flow and/or myocardial oxygenation. This may result from arterial unsaturation due to abnormal shunting or perhaps due to relative insufficiency of the hypertrophied chamber. A negative test does not mean that a lesion is not "organic," but that the congenital or chronic valve disease has not resulted in impaired myo-

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Diseases of the Chest

MASTER AND ROSENFELD

a "normal" coronary arteriogram. Also the opaque substance does not enter the smallest arteriolar radicles. This is the reason that some experts in coronary arteriography state that a negative result does not exclude coronary disease. Again, angina pectoris is

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Control

the result of many complex factors-metabolic and hemodynamic, as well as vascular. The coronary arteriogram is concerned only with anatomic abnormalities. A patient may experience angina because of transient coronary spasm or even perhaps increased blood viscosity and only in minimal narrowing of the arterial lumen. In such cases, the two-step test may as well be positive, reflecting ischemia, while the arteriogram remains normal. One should always correlate the results of the two-step test with all clinical observations. One should not be dogmatic about the results of the two-step test. The clinician must be careful not to create iatrogenic heart disease. Thus an ischemic RS-T segment may be observed in the highly nervous young woman or in the nervous menopausal woman, in a neurocirculatory young man (Fig. 21) and for some reason in those subject to paroxysmal tachycardia. Again, if one were to find an ischemic RS-T segment in a routine examination and there were no subjective or objective proof of disease, one should leave the patient lead a normal

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24: A. Z. - Woman, 46, with rheumatic heart disease, mitral stenosis and probably insufficiency, and angina pectoris. The teleroentgenogram disclosed an enlarged heart with left ventricular enlargement and straightening of the left border (see A). The Master two-step test revealed definite "ischemic" ST depression in the "immediate" and two minute V. tracings (B). The patient died one and one-half years later. This case illustrates the occurrence of coronary insufficiency during physical effort in valvular disease. FIGURE

Volume St. No.4 April. 1967

EXERCISE ELECTROCARDIOGRAPHY

life and have him return at yearly intervals for a check-up examination. Iatrogenic heart disease will thus be avoided. Meanwhile, if he were performing strenuous or dangerous work, it should be avoided.

and evaluation of coronary heart disease and for the evaluation of the adequacy of the coronary circulation on exercise in those with other forms of heart disease. "Ischemic" depression of the RS-T segment is the chief finding of a "positive" response, but "junctional" type depressions may also occur in patients who have compromised coronary artery circulation. A positive test suggests myocardial ischemia, and carries with it increased risk of cardiac morbidity or death, even in asymptomatic persons. A negative response has statistically proven favorable prognosis. The test may be performed in the presence of an abnormal control ECG, provided it is stable and does not represent "impending" myocardial infarction. Monitoring the ECG during exercise is also feasible, but does not appear to increase the overall diagnostic yield. It is worthwhile, however, in the detection of arrhythmias which may appear only in the exercise period. Monitoring techniques, both electronic and "hard-wire," depend on careful and secure application of electrodes, the most convenient of which are commercially available band-aid types. Various "bipolar" leads or conventional unipolar leads V 4' V Ii' or V8 can now also be recorded.

SUMMARY

More than two score years of experience with the standardized two-step test have confirmed it to be a safe, simple and reliable procedure for aiding in the discovery

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MASTER AND ROSENFELD RESUMEN

Mas de cuarenta a ii 0 s de experiencia con la prueba estandardizada de Master han comprobado su seguridad, sencillez e inocuidad como coadyuvante en el diagn6stico y valoraciOn de las afecciones coronarias y en la evaluaci6n de la eficacia de la circulaci6n coronaria durante el ejercicio en sujetos con otros tipos de afecciones cardiacas. La depresi6n "isquemica" del complejo SR-T es el principal indicio de la prueba "positiva", pero otros tipos de depresi6n pueden tambien ser observados en sujetos con circulaci6n coronaria comprometida. La prueba positiva indica isqueMia miocardica y con lleva un riesgo mas alto de morbilidad cardiaca. Aun en sujetos asintomaticos una respuesta negativa lleva aparejada un progn6stico favorable, estadisticamente comprobado. La prueba puede ser realizada en presencia de un ECG de control anormal, siempre que sea "estabilizado" y no indique infarto miocardico inminente. Es possible la obtenci6n del ECG durante el ejercicio, pero este proceder no parece aumentar el rendimiento diagn6stico. Es de valor, sin embargo, en la comprobaci6n de arritmias las que pueden aparecer solamente durante el ejercicio. Su tecnica, tanto electronica como mediante conductores alambricos, depende de la colocaci6n cuidadosa y segura de los electrodos, siendo los mas adecuados los de banda, obtenibles en el comercio. Varias derivaciones bipolares 0 las derivaciones ordinarias unipolares V 4 , V s 0 Va pueden ser actualmente registradas. RESUME

Plus de quarante ans d'experience avec Ie "two-step test" standardise ont confirme que c'est un procede simple sur et don n e en confiance, pour aider a la decouverte et l'evaluation de la maladie coronarienne, et pour l'evaluation de la qualite de la circulation coronarienne a I'effort chez les malades ayant d'autres formes de cardiopathie. La depression "ischemique" du segment RS-T est Ie signe principal d'une reponse "positive", mais les depressions siegeant a la jonction peuvent egalement survenir chez des malades dont la circulation arterielle coronarienne est compromise. V n t est positif suggere une ischemie myocardique ct comporte donc la prevision d'un risque augmente de morbidite ou de mortalite cardiaque, meme chez des personnes asymptomatiques. Vne reponse nega tive a ete statistiquement prouvee associee a un pronostic favorable. Le test peut etre pratique en presence d'un electrocardiogramme anormal, a condition que cette anomalie soit stable et ne represente pas un infarctus myocardique "menacant." La surveillance de l'electrocardiograrnme pendant l'effort est egalement possible, rna is n'ap-

Diseases of the Chest

parait pas augmenter Ie terrain diagnostique d'ensemble. Elle est cependant interessante dans la detection d'arythmies qui peuvent survenir seulement dans la periode d'effort. Les techniques de monitoring, a la fois electroniques et par til, dependent d'une application soigne use des electrodes, dont les plus pratiques sont celles qui sont fixees par des bandes et que I'on trouve dans Ie commerce. Des derivations bipolaires variees ou les derivations habituelies V 4 V S V 8 unipolaires peuvent egalement etre maintenant enregistrees. REFERENCES WOOD, P., McGREGOR, M., MAGmSON" O. AND WHITTAKER, W.: "Effort teat in angina pectoris," Brit. H earl I., 12: 363, 1950. 2 DoYLE, J. T., HESLIN, A. S., HILLEBOE, H. E., FORMEL, P. E. AND KORNS, R. F.: "A prospective study of degenerative cardiovascular disease in Albany. Report of 3 yean' experience. I. Ischemic heart disease," Am. J. Publ.

H.alth, 47: 25, 1957. 3 MASTER, A. M. AND ROSENPELD, I.: "Moni-

tored and post-exercise two-step test. Detection of silent coronary heart diJease and differential diagnosis of chest pain," lAMA" 190:

494, 1964. 4 MASTER, A. M.: "The spectrum of anPnal and noncardiac chest pain," lAMA, 187:894, 1964. 5 DAVIS, D. AND RITVO, M.: "Osteoarthritil of cervicodonal spine (Radiculitil) s i m u I at i n g coronary artery disease: clinical and roentgenologic findings," New Engl. /. M,d., 238:857,

1948.

6 SCBOTT, A.: "Pain in left chest: some considerations in general practice," Med. Prlsl,

220:474, 1948. 7 MASTER, A. M. AND ROSENFELD, I.: "Criteria

for the clinical application of the "two-step" test. Obviation of false-negative and false-positive responses," lAMA, 178: 283, 1961. 8 MASTER, A. M. AND GELLER, A. J.: "Magnitude of silent coronary disease," N ew York

State I. Med., 64: 2865, 1964. 9 MASTER, A. M.: "Iproniazid (Marsilid) in angina pectoris," Am. Heart I., 56:570, 1958. 10 MASTER, A. M. AND OPPENHEIMER" ENm T.: "A single exercise tolerance test for circulatory efficiency with standard tables for normal individuals," Am. /. M. Sc., 177: 223, 1929. 11 MASTER, A. M.: "The two-step test of myocardial function," Am. Hear' I., 10:495, 1935. 12 SELIG, A.: "Die funktionelle Herzdiagnostik," Pral. med. Wchnlchr., 30:418, 1905. 13 RApPORT, D. L.: "The systolic blood preuure following exercise; with remarb on cardiac capacity," Arch. Int. M.d., 19:981, 1917. 14 WILSON, MAY: "Exercise tolerance of children with heart disease as determined by standardized test exercises," /AMA, 76: 1629, 1921. 15 MAGNUs-ALSLEBEN, E.: "'Ober FunktioDlpriifungen des Herzens," Klin. W chlchr., 9: 29, 1924. 16 FELBERBAUM, D. AND FINESILVER, B.: "A simplified test of cardiac tolerance," M. I. and Record, 126: 36, 1927. 17 BRITTINGHAM, H~ H. AND WHITE, P. D.: "Cardiac functional tesu," JAMA, 79: 1922, 1901. 18 BARJUNGER, T. B. Ja. AND TESCBNEIl, J.: "The treatment of cardiac insuSiciency by a new method of exercise with dumb-bella and ban," Arch. Int. Med., 16: 795, 1915.

Volume ~1. No.4 April. 1967

EXERCISE

~~ECTROCARDI~RAPHY

19 BAIUlINGER, T. B. JR.: "The circulatory reaction to graduated work as a test of the. he~'s functional capacity," Arch. In'. M.d., 17: 963, 1916. 20 BARRJNGER, T. B. JR.: "Studies of the heart's functional capacity," Arch. In'. M.d., 20: 829, 1917. 21 BARRINGER, T. B. JR.: "Exercise tolerance in heart disease," lAMA, 79:2205, 1922. 22 MANN, H.: "Circulatory reactions to exercise during convalescence from infectious diseases," Arch. Int. M.d., 21 :682, 1918. 23 CoTTON, T. F., RApPORT, D. L. AND LEWIS, T.: "After effects of exercise on pulse rate and systolic blood preuure in cases of "irritable heart," H.art, 6: 269, 1917. 24 MENDELSOHN, M.: "Die Erholung als Mass der Herz-Function," V.rhandl. d. Kon,. f. inn. M.d., p.200, 1901. 25 GUUPNER: "Die mechanische Priifung und Beurtheilung der Herzleistung," Berl. Klinik, No. 174, 1902. 26 BENEDICT, F. G. AND CARPBNTER, T. M.: "The influence of muscular and mental work on metabolism and the efficiency of the human body as a machine," U. S. Dept. of Agriculture Office of Experiment Stations, Bull. No. 208, 1909. 27 KROOH, A.: "A bicycle ergometer and respiration apparatus for the experimental study of muscular work," Sktmdifl. Arch. f. Ph'Ysiol., 30: 375, 1913. 28 CATHCART, E. P., WISHART, G. M. AND McCALL, J.: "An ergometer adaptable for either hand or foot movements," I. Ph'Ysiol., 58: 92, 1923, 1924. 29 GILLESPIE, R. D., GIBSON, C. R. JR. AND MURRAY, D. S.: "The effect of exercise on pulse rate and blood preSlUl'e," H.ar', 12: 1, 1925. 30 EINTHOVEN, W.: "Weiteres iiber das Elektrokardiogramm," Archiv. filr Ph'Ysiolo,ie, 122: 517, 1908. 31 WOOD, F. C., WOLFERTH, C. C. AND LIVESBV, MARv M.: "Angina pectoris: the clinical and electrocardiographic phenomena of the attack and their comparisons with the effects of experimental temporary coronary occlusion," Arch. Int. M ed., 47: 339, 1931. 32 SCHERP, D. AND GOLDHAMMER, S.: "Zur Friihdiagnose der Angina Pectoris mit Helfe del Elektrokardiogramma," Z t s c hr. f. kline M,d., 124: 111, 1933. 33 KATZ, L. AND LANDT, H.: "The effect of ltandardized exercise in the four lead electrocardiogram," Am. I. M. Sc., 189: 346. 1935. 34 MISSAL, M. E.: "Exercise test and the electrocardiograph in the study of angina pectorU," An,.. Int. Med., 11: 2018, 1938. 35 RJsEMAN, J. E. F., WALLER, J. V. AND BROWN, M. G.: "The electrocardiogram during attack of angina pectoris: its characteristics and diagnoatic significance," Am. Heart I., 19: 683, 1940. 36 ROBB, G. P.: "Coronary artery disease, stress teats," M ,d. Annals of District of Columbia, 20: 313, 1951. 37 MATTlNGLV, T. W., FANCHER, P. S., BAUBR, F. L. AND ROBB, G. P.: ClThe value of the double standard two-ltep exercise tolerance test in detecting coronary disease in a follow-up study of 1,000 military personnel," Army Mee!. Service Graduate School Res. Rep., Walter Reed Anny Medical Center, Wuhington, D. C. 1954.

38 MASTER, A. M. AND JAPFE, H. L.: "The electJ:OCUdiographic changes after exercise in angina ~ctoril:·]. M,. Sinai Hosp., 7 :629, 1941. 39 HOLTER, N. J. AND GENOEULLI, J. A.: "Remote recording of physiological data by radio," Rocky Moun'ain M. I., 46: 749, 1949. 40 DUNN, F. L. AND RAHM, W. E. 1R.: Electrocardiography: modem trends in InJtrumentation and. visual and direct recording electrocardiography," Ann. In'. M.d., 32: 611, 1950. 41 FREIMAN, A. H., TOLLES, W., CAIlBERV, W. J., RUEGSEGGER., P., ABARQUEZ, R. F. AND LADUE, J. S.: "The electrocardiogram during exercise," Am. J. Cardiol., 5: 506, 1960. 42 BELLET, S., DELIYIANNI8, S. AND ELIAKlM, M.: "The electrocardiogram during exercise as recorded by radioelectrocardiography. Comparison with the post-exerciJe electrocardiogram (Master two-step test) ," Am. I. Cardiol., 8 : 385, 1961. 43 BELLET, S., ELIAKIM, M., DELIYIANNIS, S. AND LAVAN, D.: "Radioelectrocardiography during exercise in patients with angina pectoris," Ci,culation, 25:5, 1962. 44 ROSENFELD, I., MASTER, A. M. AND ROSENFELD, CAMILLA: "Recording the electrocardiogram during the performance of the Master two-step test. I," Circulation, 29: 204, 1964. 45 ROSENFELD, I. AND MASTER, A. M.: "Recording the electrocardiogram during the performance of the Muter two-step test. II," Circulation, 29: 212, 1964. 46 MASON, R. E., LlltAR, I. N. AND ROSE, R. S.: "New system of multiple leads in exercise electrocardiography. Comparison with coronary arteriography," Circulation, 30: 123, 1964. 47 MASTER, A. M. AND ROSENFELD, I. : "The two-step exercise test-current statui after 40 yean," Modem Conc.pts CardiovtJS. Dis. (in press) . 48 GROSSMAN, L. A. AND GROSSMAN, M.: "Myocardial infarction precipitated by Master twostep test," JAMA, 158: 179, 1955. 49 SIMONSON, E. AND KEvs, A.: "The electrocardiograph exercise telt: Chan~in the scalar ECG and in the mean spatial and T vector in two types of exercise; e eet of absolute and relative body weight and comment on normal standards," Am. Heart I., 52: 83, 1956. 50 MASTER, A. M.: "The 'two-step' exercise electrocardiogram: its ute in heart diseuea, including valvular heart disease of adults," Bull. St. Francis Sanatorium, 10: I, 1953. 51 MASTER, A. M. AND ROSENPELD, I.: "Can the amount of S-T segment depreuion after the 'two-step' test be correlated with the severity of ischemic heart disease?" Am. I. Cardiol., 15: 139, 1965 (abatract). 52 ROBB, G. P. AND MAR~s, H. H.: "Latent coronary artery disease: determination of its presence and severity by exercise electrocardiogram," Am. I. Cardiol., 13: 603, 1964. 53 MASTER, A. M.: "Treatment of coronary thrombosis and angina pectoris," M.tl. Cliftics of North America, New York Number, Nov., 873, 1935. 54 EVANS, W. AND McR..u, C.: "The leaer electrocardiographic signs for cardiac pain," Brit. H.art I., 14:429, 1952. 55 MALHOTRA, R. P. AND PATHANIA, N. S.: uS_T segment configuration in angina pectoris," Indian Ht. I., 6: 176, 1954. 56 MYERS, G. B. AND TALKERS, F. N.: "The electrocardiographic diagnosis of acute myocardial ischemia," Ann. In'. M.d., 43:361, 1955.

MASTER AND ROSENFELD

57 FEUILTAULT.. R.: "Two-step with electrocardiogram. Its value to detect or evaluate coronary artery disease," Canadian Services M. I ... 12: 926, 1956. 58 MANNING.. G. W.: "The electrocardiogram of the two-step exercise stress test," Am. Heart I ... 54: 823, 1957. 59 ROBB.. G. P., MARKS.. H. H. AND MATTINGLY.. T. W.: "The value of the double standard two-step exercise test in detection of coronary disease: a clinical and statistical follow-up study of military personnel and insurance applicants," Tr. Assoc. Life Insur. Med. Dir. America.. 40:52, 1956. 60 MATTINGLY.. T. W., ROBB.. G. P. AND MARKS.. H. H.: "Electrocardiographic stress tests in suspected coronary disease; a long-term statistical evaluation of the types of responses to the double standard two-step ex e r cis e test and the anoxemia test," Walter Reed Army Institute of Research.. No. 75, 1957. 61 LEPESCHKIN.. E. AND SURAWICZ, B.: "Characteristics of true-positive and false-positive results of electrocardiographic Master two-step exercise tests," New Engl. I. Med., 258:511, 1958. 62 MASTER.. A. M. AND ROSENFELD.. I. : "The 'two-step' exercise test brought up to date," New York State I. Med... 61: 1850, 1961. 63 MASTER.. A. M. AND ROSENFELD, I.: "Criterion of positive two-step exercise test," New York State I. Med... 66:2641, 1966. 64 FRIEDBERG.. C. K., JAFFE.. H. L., PORDY, L. AND CHESKY.. K.: "The two-step exercise electrocardiogram. A double-blind evaluation of its use in the diagnosis of angina pectoris," Circulation.. 26: 1254, 1962. 65 ROMAN.. L. AND BELLET.. S.: "Significance of the QX/QT ratio and the QT ratio (QTr) in the exercise electrocardiogram," Circulation.. 32: 435, 1965. 66 MASTER.. A. M. AND JAFFE.. H. L.: "Complete functional recovery after coronary occlusion and insufficiency," lAMA .. 147: 1721, 1951. 67 GUBNER.. R.: "An appraisal of the exercise electrocardiogram test. Part I. Applications, significance, and criticisms," I. Occup. M ed... 2 :57, 1960. 68 GUBNER.. R.: "Determinants of ischemic electrocardiographic abnormalities and chest pain. Part I I. The exercise electrocardiogram test," I. Occup. Med... 3: 110, 1961. 69 Yu.. P. N. G., BRUCE.. R. A., LOVEJOY.. F. W. JR. AND McDOWELL.. M. E.: "Variations in electrocardiographic responses during exercise; studies of normal subjects under unusual stresses and of patients with cardiopulmonary diseases," Circulation.. 3: 368, 1951. 70 RUMBALL.. C. A. AND ACHESON.. E. D.: "Electrocardiograms of healthy men after strenuous exercise," Brit. Hearl I ... 22 :415, 1960. 71 BELLET.. S., ELIAKIM.. M., DELIYIANNIS.. S. AND FIGALLO.. E. M. : "Radioelectrocardiographic changes during strenuous exercise in nonnal subjects," Circulation.. 25: 686, 1962. 72 HUNT.. E. A.: "Electrocardiographic study of 20 champion swimmen before and after 110 yard sprint swimming competition," Can ad. M. I ... 88: 1251, 1963. 73 ROSE.. K. D. AND DUNN.. F. L.: "Telemeter electrocardiography: a study of heart function in athletes," Nebraska State M ed. I., 49: 447, 1964. 74 DOAN.. A. E., PETERSON, D. R., BLACKMAN.. J. R. AND BRUCE.. R. A.: "Myocardial ischemia

Diseases of

the Chest

after maximal exercise in healthy men. A method for detecting potential coronary heart disease," Am. Heart I., 69: 11, 1965. (Abst. Circulation.. 32: 1045, 1965). 75 BRUCE.. R. A., MAZARELLA, J. A., JORDAN, J. W. AND GREEN, E.: "Quantitation of QRS and ST segment responses to exercise," Am. Heart I ... 71 :455, 1966. 76 BERKSON.. D. M., STAMLER, H. AND JACKSON, W.: "The precordial electrocardiogram during and after strenuous exercise, "Am. I. Cardiol., 18:43, 1966. 77 SHEFFIELD.. L. T., HOLT, J. H. AND REEVES.. T. J.: "Exercise graded by heart rate in electrocardiographic testing for angina pectoris," Circulation.. 32: 622, 1965. 78 ROWELL.. L. B., TAYLOR.. H. L., SIMONSON, E. AND CARLSON.. W. S.: "The physiologic fallacy of adjusting for body weight in performance of the Master two-step test," Am. Heart I., 70:461, 1965. 79 Hoyos.. G. M.: "Different degrees in positivity of Master's 'two-step' test for coronary insufficiency," Malattie Cardiovascolari.. 7: 1, 1966. 80 ROGERS .. W. R. AND HURST, W. D.: "Moderate exercise testing in ischemic heart disease," Northwest Med... 63: 702, 1964. 81 ROBINSON.. S.: "Experimental studies of physical fitness in relation to age," Arbeitsphysiologie.. 10:251, 1938. 82 FORD.. A. B. AND HELLERSTEIN.. H. K.: "The energy of the Master two-step test," lAMA, 164: 1868, 1957. 83 KATTUS.. A. A. AND MACALPIN, R. N.: "Exercise therapy for angina pectoris," Abstracts, Circulation.. 32: 122, 1965. 84 FRANCO, S. C., GERL.. A. J. AND MURPHY.. G. T.: "Periodic health examinations: a longterm study 1949-1959," I. Occup. Med., 3: 13, 1960. 85 HELLERSTEIN, H. K., PROZAN, G. B., LIEBOW, I. M., DOAN.. A. E. AND HENDERSON, J. A.: "Two-step exercise test as a test of cardiac function in chronic rheumatic heart disease and in arteriosclerotic heart disease with old myocardial infarction," Am. I. Cardiol., 7: 234, 1961. 86 JOHNSON.. R. L.: "The Telemetered Electrocardiogram," Medical Education for National Defense.. Symposium on Biomedical Monitoring. USAF School of Aerospace Medicine, Aerospace Medical Division, Brooks AFB, Texas, 1964, pp. 50-70. 87 BARRON.. J., KERKHOF, A. C. AND McEWAN.. A.: "The effect of digitalis on the electrocardiograms following exercise in normal adult males," Minn. Med... 48:873, 1965. COMMENT The article by Drs. Arthur M. Master anti Isadore Rosenfeld en tit led, I IExercise electrocardiography as an estimation of cardiac function," which appears in this issue of DISEASES OF THE CHEST, is the result of a lifetime of research and scientific endeavor on the part of the senior author, Dr. Arthur M .. M aster of New York City. The Master two-step test is widely accepted throughout the world and the editors of DISEASES OF THE CHEST are pleased to present this article in this issue of the journal. Because of its length.. it was at first planned to publish this in serial form over a number of months; however.. because of the importance of the subject, the excellent illustrations and the extensive reference list.. the Editorial Board of DISEASES OF THE CHEST has agreed to publish the entire article in one issue.

Volume ~l, No.4 April, 1967

EXERCISE ELECTROCARDIOGRApHY

Next month, DISEASES OP THE CREST will be /lleased to publish Ihe Second Pouflders Leclure entitled, It Eighty years afler the /irst ,lim/lse of the tubercle bacillus" by Dr. lay .A rth.r Myers, Emeritus Professor of Medinne, Preventive Medicine and Public Health, University of Minnesota. The Founders Lecture was established by the Board of Relents of the Amencan Colle,e of Chest Physicians to be delivered at e a c h International Congress of the Colle,e. It is a tribute to the College that Dr. Myers was invited to /Jresent this lecture at the IX International Con,ress on Diseases of the Chest in Co/Jeflhagm, Denmark in August, 1966. There is no one who has been more closely connected with the fight against tuberculosis than

Dr. Myers. We aler' our readers throu,hout the world, esp,cially in those countries where tuberculosis is still endemic, not to miss the May issue of the journal. It is contrary to the policy of DISEASES OP THE CHEST to publish lengthy articles, especially sinc, there is such a great d em an d for s/Jue in our journal. Occasionally, how,ver, in the interest of our r,aders, we will publish an artiele of greater than usual length. We trusl these will b. well received. Murray Komfeltl M analinl Editor For reprints, please write: Dr. Master, 125 East 72nd Street, New York City.

REPRODUCIBILITY OF THE INDICATOR-DILUTION METHOD USING pu Femoral artery 1l0w has been measured by the Indlcator-dllutlon method In man using radio-Iodinated serum albumin and cholegrafln. Cardiac output curves were also obtained and from the results, total blood volume, circulation times and limb blood volume were calculated. 1111 was shown to have advantages over 1111 and a compact semiautomatic Instrument was constructed to obtain the tlme-concentratlon curves. As a result of a

year's experience with 1111 a new version of the instrument has been constructed which la simple to use and has safety cIrcuits to prevent faulty technique. A total of 285 femoral artery curves and 189 cardiac output curves have been recorded In 101 patients. HOBBS,

}.

T. AND EDWARDS, E. A.: "Reproducibility of

the indicator-dilution method using lUI in haemodynamic studies," I. GI,JiOFtlJ. 5."., 7:34, 1966.

ARIZONA CHEST DISEASE SYMPOSIUM The 1967 Arizona Chest Disease Symposium and William F. Miller, Associate Professor of will be held at the Ramada Inn, Tucson, on Medicine, University of Texas Southwestern Saturday and Sunday, April 8 and 9. Speakers Medical School, Dallas. are: Gerald Bawn, Chief, Pulmonary Section, The registration fee is $10.00, which includes VA Hospital, Cleveland; Harriet L. Hardy, As- two luncheons. No registration fee for medical sistant Medical Director in Charge of Occupa- students, interns or residents. Advance registrational Medical Service, Massachusetts Institute tion is urged by writing: Arizona Chest Diseue of Technology; Rejane M. Harvey, Associate Symposium, P. O. Box 6067, Tucson, Arizona Professor of Medicine, Col u m b i a University; 85716.