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Cardiac dysrhythmias associated with exercise stress testing
Cardiac Dvsrhvthmias Associated with Exercise &t& Testing
MICHAEL T. ANDERSON, MD GERALD B. LEE, MD BRIAN C. CAMPION, MD KURT AMPLATZ, MD NAIP TUNA, MD, PhD, FACC Minneapolis,
Minnesota
The exercise electrocardiograms and coronary artertograms of 119 patients were examined to evaluate the significance of dysrhythmias associated with exercise testing. The overall incidence of dysrhyth mias before, during and after exercise was 19 percent. The frequerr cy of dysrhythmias was greater (26 percent) in patients with a posC tlve exercise test than in patlents with a negative exercise test (11 percent). The results of the exercise te’sts were correlated wtth coronary arteriographic findings to detect false positive and false negative results. There was no significant statistical difference in the frequency of dysrhythmias between patients who responded positively and those who responded negatively to exercise. The timing of the dysrhythmia (before, during or after exercise) was not different in the 2 groups. We conclude that dysrhythmias associated with exercise testing should raise the index of suspicion of underlying coronary artery d&ease but should not be used as a criterion for a positive test.
Exercise stress testing is well established as a clinical tool in the diagnosis of coronary insufficiency. Its use in the diagnosis of coronary heart disease has been widespread since Master et al.’ studied the electrocardiogram obtained after performance of the standard e-step test of Master and Oppenheimer.2 Recently, Doan and others have carried out submaximal and maximal exercise testing using a treadmill.3 Although there is general agreement on the ST-T changes required for a positive test, controversy remains on the significance of dysrhythmias occurring in exercise testing. Our study compares the incidence of cardiac dysrhythmias during exercise testing with the severity of coronary arterial narrowing demonstrated by selective coronary arteriography. Methods
From the Section of Cardiology, Department of Medicine, and the Department of Radiology, University of Minnesota, Minneapolis, Minn. This investigation was supported by Cardiovascular Research Program Project Grant HE-06314-06 and National Heart and Lung Institute Grants HE-06527-06 and 0685-5202-02. Manuscript received April 21, 1972, accep’fed June 16,1972. Address for reprints: Naip Tuna, MD. University Hospitals. Box 481. Minneapolis, Minn. 55455.
The study group consisted of 119 consecutive patients aged 12 to 65 years. The subjects underwent exercise stress testing and coronary arteriography between June 1965 and November 1970 at the University of Minnesota Health Sciences Center. All patients were evaluated because of symptoms suggestive of coronary insufficiency with 2 exceptions: One boy aged 12 and another aged 13 underwent exercise testing and coronary arteriography as part of a study performed in family members of patients with hyperbetalipoproteinemia. Coexisting heart disease (congenital, valvular or pericardial disease) was not suspected in any of the 119 patients. Patients with a metabolic abnormality other than disturbed lipid transport and those receiving digitalis therapy were excluded from the study. The age and sex distribution of the 119 patients in the study is shown in Table I; 64 were male and 31 female; the average age was 46 and 43 years, respectively. The average age of all subjects studied was 44 years and was equivalent for both types of exercise testing. Patients with a positive exercise test were older (average 50 years) than those with a negative exercise test (average 41 years). The incidence of positive exercise tests was higher in male (61 percent) than in female (20 percent) subjects.
November 20.1972
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Volume 30
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Fifty-three patients performed 2Exercise testing: step double tests using the method of Master et a1.l and 66 performed treadmill maximal exercise tests by the method of Doan et al.3 A single monitoring lead was recorded at 30 second intervals during exercise testing. In addition to the monitoring lead, each patient had a conventional 12 lead electrocardiogram recorded on a 6 channel direct-writing oscillograph before and immediately after exercise and at 1, 2, 4, 6, 8 and 10 minutes after exercise. Patients whose postexercise electrocardiogram did not return to pre-exercise levels within 10 minutes were observed for longer periods. The exercise electrocardiogram was interpreted as positive when there was horizontal S-T segment depression of 1 mm or more during or after exercise. The exercise electrocardiograms were examined for the presence of dysrhythm& before, during and after the stress of exercise. Dysrhythmias were classified according to origin (atrial, junctional or ventricular) and frequency (single, multiple or repetitive). Extrasystoles separated by intervals of sinus rhythm were termed multiple; premature beats following each other in close proximity were considered repetitive extrasystoles. Coronary arteriography: All patients underwent selective coronary arteriography by means of the Amplatz technique.4 The injected coronary arteries were recorded on a cut-film changer in at least 2 projections. The coronary arteriograms were graded as previously reported.“+s The degree of luminal narrowing was noted for each of the 4 arterial segments: the right, left main, left anterior descending and left circumflex coronary arteries. Each coronary artery was graded according to its greatest degree of lumen narrowing as follows: 25 percent or less narrowing l+, 50 percent or less narrowing 2+, narrowing greater than 50 percent 3+, and total occlusion 4+. If there were no demonstrable areas of narrowing, the artery was considered normal (grade 0). A “coronary disease score” was computed to define the total degree of coronary artery disease. Narrowing of an artery graded 3+ was assigned a score of 3, and complete occlusion was assigned a score of 4. The total coronary disease score for each patient was calculated by adding grade 3 and 4 lesions of the individual coronary arterial segments. Thus, a patient with complete occlusion of the right coronary artery (score 4) and 75 percent occlusion of the left anterior descending coronary artery (score 3) had a total coronary disease score of 7. Grade 1 and grade 2 arterial narrowings were not used in calculating the coronary disease score because they are thought not to produce significant hemodynamic alterations. The results of exercise testing were compared with the presence of segmental narrowing on coronary arteriograms to obtain the incidence of false positive and false negative exercise tests. A negative exercise test was considered falsely negative if any coronary artery had more than 50 percent segmental narrowing. If there was less than 25 percent segmental narrowing in the presence of a positive exercise test, the test was considered falsely positive. Results The results of exercise stress testing and coronary arteriography are shown in Table II. Thirty-seven of 66 treadmill tests and 21 of 53 double 2-step tests were positive. As expected, the average coronary disease score in both forms of exercise testing was much
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ET AL.
TABLE
I
Results of Exercise lest
Related to Age and Sex
MaleSubjects
FemaleSubjects Age
Age Test Treadmill Positive Negative
no.
Mean
Range
no.
Mean
33 16
49.7 37.6
(34-65) (1257)
4 13
41.7 42
...
17
49
Total 2-Step Positive Negative
18 17
Total
35
TABLE
... 50 41.8
...
Range
(3251) (21-59)
...
...
(37-60)
3
w-55)
15
51 41.9
w-53)
(41-59)
...
18
...
.. .
II
Results of Exercise Tests Correlated Arteriographic Findings
with Coronary
no.
Average CHD Scare
Positive Negative
37 29
7.0 1.2
2-Step Positive Negative
21 32
7.1 1.8
119
4.2
Exercise Tests Treadmill
Total CHD
= coronary
TABLE
heart
disease.
Ill
Incidence
of False Positive and False Negative
no.
no.
%
no. With Single VesSel Disease
37 29
2 7
5.4 24.0
0 4
21 32
2
9.5
0
11
34.0
5
Tests
Type
Exercise Tests
False Results
Treadmill (+I (-1 2Step (+I (-1
higher in subjects with positive tests’ than in those with negative tests2Jj Seven patients with negative treadmill tests (24 percent) and 11 patients with a negative double 2step test (34 percent) had greater than 50 percent segmental narrowing of at least 1 coronary artery; these were considered false negative tests (Table III). Half of the patients with false negative results had single vessel disease. False positive results were
Volume 30
CARDIAC
TABLE
IV
Incidence
of Dysrhythmias
in Exercise Tests Arrhythmias
Total Tests
no.
%
Treadmill Positive Negative
37 29
1.2 4
32 14
Totals
66
16
25.7
2Step Positive Negative
21 32
3 3
14 9
Totals
53
6
11
Test
TABLE
Chi Square Test
NS
NS
V
Types of Dysrhythmias Dysrhythmia Exercise Test Treadmill Positive
Negative
2-Step Positive
Negative
CHD Score
Timing
Type
Single APC with aberrant conduction Sinus arrest Repetitive APC’s Single APC Single APC APC and PVC APC and PVC Multiple PVC’s Single PVC Multiple PVC’s Multiple PVC’s Multiple PVC’s Multiple PVC’s Single PVC
11
After After After After Before During and At rest During and During After After After During and During and
after after
after after
12 7 7 ... 3 ... 10 6 7 8 7 7
...
Single PVC Single PVC Bigeminy
During After After
0 0 0
3 PVC’s in succession
After
3
Single PVC Single PVC Single PVC
After Before After
8 4 12
Before After After
8 0 0
PVC = premature
ven-
Repetitive unifocal Repetitive unifocal Single PVC
APC = atrial premature tricular contraction.
PVC’s PVC’s
contraction;
much less common: 5.4 percent in patients taking the treadmill and 9.5 percent in those performing the double 2-step test. The incidence of dysrhythmias in subjects with positive and negative exercise tests is seen in Table IV. The overall incidence of dysrhythmias in the study was 19 percent. The incidence of dysrhythmias in the double Master test alone was 11 percent. Dys-
DYSRHYTHMIAS
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rhythmias were most common in subjects with a positive response to exercise. Patients with a positive treadmill test had a 3-fold higher incidence of dysrhythmias than patients with a negative response. The chi square test was used to evaluate the statistical significance of the result of exercise testing and the dysrhythmias present. There were no differences of statistical significance in the treadmill test or Master test, or when the totals of both tests were combined. The type and timing (before, during or after exercise) of the dysrhythmias encountered and the coronary disease score of the individual patients are shown in Table V. Supraventricular dysrhythmias occurred only in patients with positive responses to the treadmill test. Premature ventricular contractions were seen in patients with positive and negative responses but were more common in the former. Most of the dysrhythmias occurred after rather than during exercise regardless of the coronary disease score or the result of exercise testing. There were no life-threatening dysrhythmias in this study, thus indicating the safety of exercise testing. The most disturbing dysrhythmias were precipitated by exercise in subjects with negative treadmill tests. Ventricular bigeminy was seen in a woman with a normal coronary arteriogram. Repetitive premature ventricular contractions, 3 in a row, occurred in a 12 year old boy who had hyperbetalipoproteinemia and 3+ narrowing of the right coronary artery. Discussion Reported criteria for a positive response to exercise testing include the followings: (1) horizontal S-T segment depression of 1 mm or more; (2) negative U waves; (3) atrioventricular conduction defect; (4) transient bundle branch block; and (5) dysrhythmias (bursts of ectopic beats, ventricular tachycardia and ventricular fibrillation). The downward shift of the S-T segment is the most reliable of these criteria in predicting the presence of “coronary insufficiency.“r The presence of dysrhythmias was considered a criterion for a positive Master 2-step test in several early reports.llg However, later reports advised caution in the use of dysrhythmias in interpreting the test.ls*ll Master and Rosenfeld12 concluded that the presence of dysrhythmias did not constitute a positive result in the Master 2-step test. Coronary arteriography was not performed in these studies, and the diagnosis of coronary disease was based on clinical observations and the presence of S-T segment changes only. Mann and Burchell,13 in reviewing the subject of dysrhythmias in exercise testing, concluded that premature ventricular contractions precipitated by the Master 2-step test are usually indicative of coronary insufficiency. In their series, patients with premature ventricular contractions before exercise were less likely to have clinical evidence of coronary heart disease. Berkson et al.l4 found no relation between iso-
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lated premature ventricular contractions and the presence of S-T segment depression during treadmill exercise. Premature ventricular contractions that were multiple or multifocal were associated with S-T segment depression in 2 cases. In several studies, no correlation was found between the occurrence of S-T segment depression during exercise testing and dysrhythmias. Premature ventricular contractions were found with equal frequency in positive and negative responders to the Master 2-step15 and treadmill tests.16 Lester et a1.17 noted 2 p’atients with supraventricular tachycardia and 2 with ventricular tachycardia during treadmill exercise testing. All had normal S-T segments and no clinical evidence of coronary insufficiency. Lamb and Hissls concluded that no assumption could be made on the basis of dysrhythmias without clinical evidence of coronary disease.
Correlation of dysrhythmias, results of exercise testing and coronary arteriography: The signifi-
ET AL.
when the data were evaluated using the chi square test. This finding is in agreement with the observations of Berkson et a1.14 and others,15,16 who found no association between S-T segment changes during exercise testing ?nd dysrhythmias. The dysrhythmias in the study of Berkson et al. were usually single premature ventricular contractions, whereas our patients with positive responses to maximal exercise tended to have supraventricular dysrhythmias. The frequency of supraventricular dysrhythmias in our study may indicate impaired left ventricular performance during maximal exercise leading to left atria1 overload resulting in supraventricular dysrhythmias. The higher incidence of dysrhythmias in the treadmill test (26 percent) compared to the incidence in Master test (11 percent) may indicate the induction of dysrhythmias during maximal stress regardless of the presence of coronary heart disease. The timing of the dysrhythmias (before, during or after exercise) did not differ in subjects with a positive or negative response to either form of the exercise test. The majority of the dysrhythmias occurred during and after exercise regardless of S-T segment changes or the presence or absence of coronary heart disease on coronary arteriograms.
cance of dysrhythmias during exercise testing is bet: ter assessed when exercise testing is correlated with coronary arteriographic findings rather than clinical observation alone because of the frequency of false results in exercise testing. The presence and degree of coronary artery disease are uncertain when dysrhythmias in exercise testing are related to S-T segment changes and clinical observations without coronary arteriography. Most et al.lg found a 42 percent incidence of false negative results when comparing coronary arteriograms with S-T segment changes during the Master 2-step test. Single-vessel occlusive disease w&s not likely to cause a positive exercise test. Demany et al.20 found 10 false positive and 24 false negative tests in 75 patients evaluated with the double Master test and coronary arteriography. The incidence of false negative tests was 30 percent in a study correlating maximal exercise testing with coronary arteriography.21 Previous studies relating dysrhythmias to positive or negative exercise tests on the basis of S-T segment depression alone must be looked at skeptically because of the incidence of false results. We believe that coronary arteriography is a better means of relating dysrhythmias associated with exercise testing to coronary artery disease. Using the coronary arteriogram to set the standard for the presence or absence of coronary disease will give accurate results for the majority of patients with classic coronary atherosclerosis; however, the method will prove inaccurate for those with unusual causes of coronary insufficiency such as “small vessel disease” or the syndrome of myocardial &hernia or infarction associated with normal coronary arteriograms. The overall incidence of dysrhythmias was 19 percent in the 119 patients in our study. Dysrhythmias were most common in patients responding positively to maximal exercise, and the frequency of dysrhythmias was slightly higher in patients with positive responses to the Master test than in those with negative responses. There were no statistical differences
were also evident in subjects with a negative response to exercise testing, 4 with a negative treadmill test and 3 with negative Master test. One patient with a negative response to the treadmill test and repetitive premature ventricular contractions precipitated by exercise had 75 percent narrowing of the right coronary artery. In another patient with a negative response to treadmill testing, bigeminy developed with no evidence of coronary arterial narrowing on arteriograms. Lester et a1.l’ reported 2 cases of ventricular tachycardia precipitated by treadmill exercise in patients with no S-T segment changes or history suggestive of coronary heart disease. This finding suggests that the presence of dysrhythmias in the absence of the S-T segment criterion for a positive test cannot be interpreted as indicating underlying coronary disease. However, since dysrhythmias were more common in patients with positive exercise tests and abnormal coronary arteriograms, their presence should increase the index of suspicion of coronary artery disease. When a single monitoring electrocardiographic lead is used in the exercise test, we suggest repeating the test using alternate lead placement. In our study, a conventional 12 lead electrocardiogram was recorded simultaneously before, and at intervals after, exercise. The number of false positive and false negative exercise tests on the basis of coronary arteriography was similar to that in previous reports.ls21 The addition of dysrhythmias as a criterion for a positive test would not have changed the overall percentage of false positive and negative results and thus had no predictive value greater than that of the S-T segment changes in this study.
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Significance of dysrhythmias in patients with negative responses to exercise: Dysrhythmias
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References 1. Master AM, Frbdman R, Dack S: The electrocardiogram after standard exercise as a functional test of the heart. Amer Heart J 24:777-793.1942 2. Master AM, Oppenhefrner ET: A simple exercise tolerance test for circulatory efficiency with standard tables for normal individuals. Amer J Med Sci 177:223-242, 1929 3. Doan AE, Peterson DR, Blackman JR, et al: Myocardial ischemia after maximal exercise in healthy men. A method for detecting potential coronary heart disease. Amer Heart J 89:11-21, 1985 4. Wlbon W, Lee GB, Amplatr K: Biplane selective coronary arteriography via percutaneous transfemoral approach. Amer J Roentgen 100:332-340, 1987 5. Lee GB, Wlson W, Amptatz K, et al: Correlation of vectorcardiogram and electrocardiogram with the coronary arteriogram. Circulation 38:189-200. 1988 8. Tuna N, Lee GB, Amptstz K: The value of vectorcardiography, electrocardiography and exercise electrocardiography in the diagnosis of coronary artery disease. Correlation with coronary arteriography. In, Proc Xl Itf~ International Vectorcardiography Symposium. Amsterdam, North Holland Publishing 1971. p 388 Evaluation of type and degree of 7. Robb OR, Marks HH: changes in post-exercise electrocardiography in detecting coronary artery disease. Proc Sot Exp Biol Med 103:450452,198O 8. Dlmond EG: The Electrocardiogram in Office Practice. Springfield, Charles C Thomas, 1981 9. Master AM: The two-ste’p exercise electrocardiogram: a test for coronary insufficiency. Ann Intern Med 32:842-883, 1950 10. Master AM, Rosentold I: Criteria for the clinical application of the two-step exercise test. JAMA 178:283-289. 1981
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11. Master AM, Field LE, Donor0 E: Coronary artery disease and the “two-step exercise test.” NY J Med 57:1051-1081. 1957 12. Master AM, Rosentold I: Two-step exercise test: current status after twenty-five years. Mod Cone Cardiovasc Dis 38:19-24.1987 13. Mann RH, Burdhell MB: Premature ventricular contractions and exercise. Mayo Clin Proc 27:383-389, 1952 14. Berkson DM, Stamler J, Jackson W: The precordial electrocardiogram during and after strenuous exercise. Amer J Cardiol 18:43-51, 1988 15. Lepeschkln E, Surawkx B: Characteristics of true-positive and_ false-positive results of electrocardiographic Master two-step exercise tesis. New l%g J Med ,258:511-520, 1958 18. Gddbarg AN, Moran JR, Chtlders RW, et al: Results and correlations of multistage exercise tests in a group of clinically normal business executives. Amer Heart J 79:194-200, 1970 17. Lester RM, Sheffletd LT, Reeves TJ: Electrocardiographic changes in clinically normal older men following near minimal and maximal exercise. Circulation 38:5-14, 1987 18. Lamb LE, Hiss RG: Influence of exercise on premature contractions. Amer J Cardiol 10:209-218, 1982 19. Most AS, Kemp HO, Gortln R: Post exercise electrocardiography in patients with arteriographically documented coronary artery disease. Ann Intern Med 71:1043-1049. 1989 20. Demany MA, Tambe A, tlmmerman HA: Correlation between coronary arteriography and post-exercise electrocardiogram. Amer J Cardiol 19:528-530, 1987 21. Roftman D, Jones WB, Sheffield LT: Comparison of submaximal percise ECG test with coronary tine angiocardiogram. Ann Intern Med 72:841-847, 1970
The Amerkan
Journal of CARDIOLOGY
Volume 30
767
MICHAEL T. ANDERSON, MD GERALD B. LEE, MD BRIAN C. CAMPION, MD KURT AMPLATZ, MD NAIP TUNA, MD, PhD, FACC Minneapolis,
Minnesota
The exercise electrocardiograms and coronary artertograms of 119 patients were examined to evaluate the significance of dysrhythmias associated with exercise testing. The overall incidence of dysrhyth mias before, during and after exercise was 19 percent. The frequerr cy of dysrhythmias was greater (26 percent) in patients with a posC tlve exercise test than in patlents with a negative exercise test (11 percent). The results of the exercise te’sts were correlated wtth coronary arteriographic findings to detect false positive and false negative results. There was no significant statistical difference in the frequency of dysrhythmias between patients who responded positively and those who responded negatively to exercise. The timing of the dysrhythmia (before, during or after exercise) was not different in the 2 groups. We conclude that dysrhythmias associated with exercise testing should raise the index of suspicion of underlying coronary artery d&ease but should not be used as a criterion for a positive test.
Exercise stress testing is well established as a clinical tool in the diagnosis of coronary insufficiency. Its use in the diagnosis of coronary heart disease has been widespread since Master et al.’ studied the electrocardiogram obtained after performance of the standard e-step test of Master and Oppenheimer.2 Recently, Doan and others have carried out submaximal and maximal exercise testing using a treadmill.3 Although there is general agreement on the ST-T changes required for a positive test, controversy remains on the significance of dysrhythmias occurring in exercise testing. Our study compares the incidence of cardiac dysrhythmias during exercise testing with the severity of coronary arterial narrowing demonstrated by selective coronary arteriography. Methods
From the Section of Cardiology, Department of Medicine, and the Department of Radiology, University of Minnesota, Minneapolis, Minn. This investigation was supported by Cardiovascular Research Program Project Grant HE-06314-06 and National Heart and Lung Institute Grants HE-06527-06 and 0685-5202-02. Manuscript received April 21, 1972, accep’fed June 16,1972. Address for reprints: Naip Tuna, MD. University Hospitals. Box 481. Minneapolis, Minn. 55455.
The study group consisted of 119 consecutive patients aged 12 to 65 years. The subjects underwent exercise stress testing and coronary arteriography between June 1965 and November 1970 at the University of Minnesota Health Sciences Center. All patients were evaluated because of symptoms suggestive of coronary insufficiency with 2 exceptions: One boy aged 12 and another aged 13 underwent exercise testing and coronary arteriography as part of a study performed in family members of patients with hyperbetalipoproteinemia. Coexisting heart disease (congenital, valvular or pericardial disease) was not suspected in any of the 119 patients. Patients with a metabolic abnormality other than disturbed lipid transport and those receiving digitalis therapy were excluded from the study. The age and sex distribution of the 119 patients in the study is shown in Table I; 64 were male and 31 female; the average age was 46 and 43 years, respectively. The average age of all subjects studied was 44 years and was equivalent for both types of exercise testing. Patients with a positive exercise test were older (average 50 years) than those with a negative exercise test (average 41 years). The incidence of positive exercise tests was higher in male (61 percent) than in female (20 percent) subjects.
November 20.1972
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Volume 30
763
CARDIAC
DYSRHYTHMIAS
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Fifty-three patients performed 2Exercise testing: step double tests using the method of Master et a1.l and 66 performed treadmill maximal exercise tests by the method of Doan et al.3 A single monitoring lead was recorded at 30 second intervals during exercise testing. In addition to the monitoring lead, each patient had a conventional 12 lead electrocardiogram recorded on a 6 channel direct-writing oscillograph before and immediately after exercise and at 1, 2, 4, 6, 8 and 10 minutes after exercise. Patients whose postexercise electrocardiogram did not return to pre-exercise levels within 10 minutes were observed for longer periods. The exercise electrocardiogram was interpreted as positive when there was horizontal S-T segment depression of 1 mm or more during or after exercise. The exercise electrocardiograms were examined for the presence of dysrhythm& before, during and after the stress of exercise. Dysrhythmias were classified according to origin (atrial, junctional or ventricular) and frequency (single, multiple or repetitive). Extrasystoles separated by intervals of sinus rhythm were termed multiple; premature beats following each other in close proximity were considered repetitive extrasystoles. Coronary arteriography: All patients underwent selective coronary arteriography by means of the Amplatz technique.4 The injected coronary arteries were recorded on a cut-film changer in at least 2 projections. The coronary arteriograms were graded as previously reported.“+s The degree of luminal narrowing was noted for each of the 4 arterial segments: the right, left main, left anterior descending and left circumflex coronary arteries. Each coronary artery was graded according to its greatest degree of lumen narrowing as follows: 25 percent or less narrowing l+, 50 percent or less narrowing 2+, narrowing greater than 50 percent 3+, and total occlusion 4+. If there were no demonstrable areas of narrowing, the artery was considered normal (grade 0). A “coronary disease score” was computed to define the total degree of coronary artery disease. Narrowing of an artery graded 3+ was assigned a score of 3, and complete occlusion was assigned a score of 4. The total coronary disease score for each patient was calculated by adding grade 3 and 4 lesions of the individual coronary arterial segments. Thus, a patient with complete occlusion of the right coronary artery (score 4) and 75 percent occlusion of the left anterior descending coronary artery (score 3) had a total coronary disease score of 7. Grade 1 and grade 2 arterial narrowings were not used in calculating the coronary disease score because they are thought not to produce significant hemodynamic alterations. The results of exercise testing were compared with the presence of segmental narrowing on coronary arteriograms to obtain the incidence of false positive and false negative exercise tests. A negative exercise test was considered falsely negative if any coronary artery had more than 50 percent segmental narrowing. If there was less than 25 percent segmental narrowing in the presence of a positive exercise test, the test was considered falsely positive. Results The results of exercise stress testing and coronary arteriography are shown in Table II. Thirty-seven of 66 treadmill tests and 21 of 53 double 2-step tests were positive. As expected, the average coronary disease score in both forms of exercise testing was much
764
November 20,1972
The American Journal of CARDIOLOGY
ET AL.
TABLE
I
Results of Exercise lest
Related to Age and Sex
MaleSubjects
FemaleSubjects Age
Age Test Treadmill Positive Negative
no.
Mean
Range
no.
Mean
33 16
49.7 37.6
(34-65) (1257)
4 13
41.7 42
...
17
49
Total 2-Step Positive Negative
18 17
Total
35
TABLE
... 50 41.8
...
Range
(3251) (21-59)
...
...
(37-60)
3
w-55)
15
51 41.9
w-53)
(41-59)
...
18
...
.. .
II
Results of Exercise Tests Correlated Arteriographic Findings
with Coronary
no.
Average CHD Scare
Positive Negative
37 29
7.0 1.2
2-Step Positive Negative
21 32
7.1 1.8
119
4.2
Exercise Tests Treadmill
Total CHD
= coronary
TABLE
heart
disease.
Ill
Incidence
of False Positive and False Negative
no.
no.
%
no. With Single VesSel Disease
37 29
2 7
5.4 24.0
0 4
21 32
2
9.5
0
11
34.0
5
Tests
Type
Exercise Tests
False Results
Treadmill (+I (-1 2Step (+I (-1
higher in subjects with positive tests’ than in those with negative tests2Jj Seven patients with negative treadmill tests (24 percent) and 11 patients with a negative double 2step test (34 percent) had greater than 50 percent segmental narrowing of at least 1 coronary artery; these were considered false negative tests (Table III). Half of the patients with false negative results had single vessel disease. False positive results were
Volume 30
CARDIAC
TABLE
IV
Incidence
of Dysrhythmias
in Exercise Tests Arrhythmias
Total Tests
no.
%
Treadmill Positive Negative
37 29
1.2 4
32 14
Totals
66
16
25.7
2Step Positive Negative
21 32
3 3
14 9
Totals
53
6
11
Test
TABLE
Chi Square Test
NS
NS
V
Types of Dysrhythmias Dysrhythmia Exercise Test Treadmill Positive
Negative
2-Step Positive
Negative
CHD Score
Timing
Type
Single APC with aberrant conduction Sinus arrest Repetitive APC’s Single APC Single APC APC and PVC APC and PVC Multiple PVC’s Single PVC Multiple PVC’s Multiple PVC’s Multiple PVC’s Multiple PVC’s Single PVC
11
After After After After Before During and At rest During and During After After After During and During and
after after
after after
12 7 7 ... 3 ... 10 6 7 8 7 7
...
Single PVC Single PVC Bigeminy
During After After
0 0 0
3 PVC’s in succession
After
3
Single PVC Single PVC Single PVC
After Before After
8 4 12
Before After After
8 0 0
PVC = premature
ven-
Repetitive unifocal Repetitive unifocal Single PVC
APC = atrial premature tricular contraction.
PVC’s PVC’s
contraction;
much less common: 5.4 percent in patients taking the treadmill and 9.5 percent in those performing the double 2-step test. The incidence of dysrhythmias in subjects with positive and negative exercise tests is seen in Table IV. The overall incidence of dysrhythmias in the study was 19 percent. The incidence of dysrhythmias in the double Master test alone was 11 percent. Dys-
DYSRHYTHMIAS
AND
EXERCISE
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rhythmias were most common in subjects with a positive response to exercise. Patients with a positive treadmill test had a 3-fold higher incidence of dysrhythmias than patients with a negative response. The chi square test was used to evaluate the statistical significance of the result of exercise testing and the dysrhythmias present. There were no differences of statistical significance in the treadmill test or Master test, or when the totals of both tests were combined. The type and timing (before, during or after exercise) of the dysrhythmias encountered and the coronary disease score of the individual patients are shown in Table V. Supraventricular dysrhythmias occurred only in patients with positive responses to the treadmill test. Premature ventricular contractions were seen in patients with positive and negative responses but were more common in the former. Most of the dysrhythmias occurred after rather than during exercise regardless of the coronary disease score or the result of exercise testing. There were no life-threatening dysrhythmias in this study, thus indicating the safety of exercise testing. The most disturbing dysrhythmias were precipitated by exercise in subjects with negative treadmill tests. Ventricular bigeminy was seen in a woman with a normal coronary arteriogram. Repetitive premature ventricular contractions, 3 in a row, occurred in a 12 year old boy who had hyperbetalipoproteinemia and 3+ narrowing of the right coronary artery. Discussion Reported criteria for a positive response to exercise testing include the followings: (1) horizontal S-T segment depression of 1 mm or more; (2) negative U waves; (3) atrioventricular conduction defect; (4) transient bundle branch block; and (5) dysrhythmias (bursts of ectopic beats, ventricular tachycardia and ventricular fibrillation). The downward shift of the S-T segment is the most reliable of these criteria in predicting the presence of “coronary insufficiency.“r The presence of dysrhythmias was considered a criterion for a positive Master 2-step test in several early reports.llg However, later reports advised caution in the use of dysrhythmias in interpreting the test.ls*ll Master and Rosenfeld12 concluded that the presence of dysrhythmias did not constitute a positive result in the Master 2-step test. Coronary arteriography was not performed in these studies, and the diagnosis of coronary disease was based on clinical observations and the presence of S-T segment changes only. Mann and Burchell,13 in reviewing the subject of dysrhythmias in exercise testing, concluded that premature ventricular contractions precipitated by the Master 2-step test are usually indicative of coronary insufficiency. In their series, patients with premature ventricular contractions before exercise were less likely to have clinical evidence of coronary heart disease. Berkson et al.l4 found no relation between iso-
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lated premature ventricular contractions and the presence of S-T segment depression during treadmill exercise. Premature ventricular contractions that were multiple or multifocal were associated with S-T segment depression in 2 cases. In several studies, no correlation was found between the occurrence of S-T segment depression during exercise testing and dysrhythmias. Premature ventricular contractions were found with equal frequency in positive and negative responders to the Master 2-step15 and treadmill tests.16 Lester et a1.17 noted 2 p’atients with supraventricular tachycardia and 2 with ventricular tachycardia during treadmill exercise testing. All had normal S-T segments and no clinical evidence of coronary insufficiency. Lamb and Hissls concluded that no assumption could be made on the basis of dysrhythmias without clinical evidence of coronary disease.
Correlation of dysrhythmias, results of exercise testing and coronary arteriography: The signifi-
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when the data were evaluated using the chi square test. This finding is in agreement with the observations of Berkson et a1.14 and others,15,16 who found no association between S-T segment changes during exercise testing ?nd dysrhythmias. The dysrhythmias in the study of Berkson et al. were usually single premature ventricular contractions, whereas our patients with positive responses to maximal exercise tended to have supraventricular dysrhythmias. The frequency of supraventricular dysrhythmias in our study may indicate impaired left ventricular performance during maximal exercise leading to left atria1 overload resulting in supraventricular dysrhythmias. The higher incidence of dysrhythmias in the treadmill test (26 percent) compared to the incidence in Master test (11 percent) may indicate the induction of dysrhythmias during maximal stress regardless of the presence of coronary heart disease. The timing of the dysrhythmias (before, during or after exercise) did not differ in subjects with a positive or negative response to either form of the exercise test. The majority of the dysrhythmias occurred during and after exercise regardless of S-T segment changes or the presence or absence of coronary heart disease on coronary arteriograms.
cance of dysrhythmias during exercise testing is bet: ter assessed when exercise testing is correlated with coronary arteriographic findings rather than clinical observation alone because of the frequency of false results in exercise testing. The presence and degree of coronary artery disease are uncertain when dysrhythmias in exercise testing are related to S-T segment changes and clinical observations without coronary arteriography. Most et al.lg found a 42 percent incidence of false negative results when comparing coronary arteriograms with S-T segment changes during the Master 2-step test. Single-vessel occlusive disease w&s not likely to cause a positive exercise test. Demany et al.20 found 10 false positive and 24 false negative tests in 75 patients evaluated with the double Master test and coronary arteriography. The incidence of false negative tests was 30 percent in a study correlating maximal exercise testing with coronary arteriography.21 Previous studies relating dysrhythmias to positive or negative exercise tests on the basis of S-T segment depression alone must be looked at skeptically because of the incidence of false results. We believe that coronary arteriography is a better means of relating dysrhythmias associated with exercise testing to coronary artery disease. Using the coronary arteriogram to set the standard for the presence or absence of coronary disease will give accurate results for the majority of patients with classic coronary atherosclerosis; however, the method will prove inaccurate for those with unusual causes of coronary insufficiency such as “small vessel disease” or the syndrome of myocardial &hernia or infarction associated with normal coronary arteriograms. The overall incidence of dysrhythmias was 19 percent in the 119 patients in our study. Dysrhythmias were most common in patients responding positively to maximal exercise, and the frequency of dysrhythmias was slightly higher in patients with positive responses to the Master test than in those with negative responses. There were no statistical differences
were also evident in subjects with a negative response to exercise testing, 4 with a negative treadmill test and 3 with negative Master test. One patient with a negative response to the treadmill test and repetitive premature ventricular contractions precipitated by exercise had 75 percent narrowing of the right coronary artery. In another patient with a negative response to treadmill testing, bigeminy developed with no evidence of coronary arterial narrowing on arteriograms. Lester et a1.l’ reported 2 cases of ventricular tachycardia precipitated by treadmill exercise in patients with no S-T segment changes or history suggestive of coronary heart disease. This finding suggests that the presence of dysrhythmias in the absence of the S-T segment criterion for a positive test cannot be interpreted as indicating underlying coronary disease. However, since dysrhythmias were more common in patients with positive exercise tests and abnormal coronary arteriograms, their presence should increase the index of suspicion of coronary artery disease. When a single monitoring electrocardiographic lead is used in the exercise test, we suggest repeating the test using alternate lead placement. In our study, a conventional 12 lead electrocardiogram was recorded simultaneously before, and at intervals after, exercise. The number of false positive and false negative exercise tests on the basis of coronary arteriography was similar to that in previous reports.ls21 The addition of dysrhythmias as a criterion for a positive test would not have changed the overall percentage of false positive and negative results and thus had no predictive value greater than that of the S-T segment changes in this study.
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References 1. Master AM, Frbdman R, Dack S: The electrocardiogram after standard exercise as a functional test of the heart. Amer Heart J 24:777-793.1942 2. Master AM, Oppenhefrner ET: A simple exercise tolerance test for circulatory efficiency with standard tables for normal individuals. Amer J Med Sci 177:223-242, 1929 3. Doan AE, Peterson DR, Blackman JR, et al: Myocardial ischemia after maximal exercise in healthy men. A method for detecting potential coronary heart disease. Amer Heart J 89:11-21, 1985 4. Wlbon W, Lee GB, Amplatr K: Biplane selective coronary arteriography via percutaneous transfemoral approach. Amer J Roentgen 100:332-340, 1987 5. Lee GB, Wlson W, Amptatz K, et al: Correlation of vectorcardiogram and electrocardiogram with the coronary arteriogram. Circulation 38:189-200. 1988 8. Tuna N, Lee GB, Amptstz K: The value of vectorcardiography, electrocardiography and exercise electrocardiography in the diagnosis of coronary artery disease. Correlation with coronary arteriography. In, Proc Xl Itf~ International Vectorcardiography Symposium. Amsterdam, North Holland Publishing 1971. p 388 Evaluation of type and degree of 7. Robb OR, Marks HH: changes in post-exercise electrocardiography in detecting coronary artery disease. Proc Sot Exp Biol Med 103:450452,198O 8. Dlmond EG: The Electrocardiogram in Office Practice. Springfield, Charles C Thomas, 1981 9. Master AM: The two-ste’p exercise electrocardiogram: a test for coronary insufficiency. Ann Intern Med 32:842-883, 1950 10. Master AM, Rosentold I: Criteria for the clinical application of the two-step exercise test. JAMA 178:283-289. 1981
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11. Master AM, Field LE, Donor0 E: Coronary artery disease and the “two-step exercise test.” NY J Med 57:1051-1081. 1957 12. Master AM, Rosentold I: Two-step exercise test: current status after twenty-five years. Mod Cone Cardiovasc Dis 38:19-24.1987 13. Mann RH, Burdhell MB: Premature ventricular contractions and exercise. Mayo Clin Proc 27:383-389, 1952 14. Berkson DM, Stamler J, Jackson W: The precordial electrocardiogram during and after strenuous exercise. Amer J Cardiol 18:43-51, 1988 15. Lepeschkln E, Surawkx B: Characteristics of true-positive and_ false-positive results of electrocardiographic Master two-step exercise tesis. New l%g J Med ,258:511-520, 1958 18. Gddbarg AN, Moran JR, Chtlders RW, et al: Results and correlations of multistage exercise tests in a group of clinically normal business executives. Amer Heart J 79:194-200, 1970 17. Lester RM, Sheffletd LT, Reeves TJ: Electrocardiographic changes in clinically normal older men following near minimal and maximal exercise. Circulation 38:5-14, 1987 18. Lamb LE, Hiss RG: Influence of exercise on premature contractions. Amer J Cardiol 10:209-218, 1982 19. Most AS, Kemp HO, Gortln R: Post exercise electrocardiography in patients with arteriographically documented coronary artery disease. Ann Intern Med 71:1043-1049. 1989 20. Demany MA, Tambe A, tlmmerman HA: Correlation between coronary arteriography and post-exercise electrocardiogram. Amer J Cardiol 19:528-530, 1987 21. Roftman D, Jones WB, Sheffield LT: Comparison of submaximal percise ECG test with coronary tine angiocardiogram. Ann Intern Med 72:841-847, 1970
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