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Similarity between women and men in manifestation of myocardial ischemia during exercise
International Journal of Cardiology, 5 (1984) 121-126 Elsevier
721
IJC 00141
Similarity between women and men in manifestation of myocardial ischemia during exercise A-Hamid Hakki, Abdulmassih S. Iskandrian and Jay Colby Likoff Cardiovascular Institute of Hahnemann University and Hospital, Philadelphia, Pennsylvania (Received 14 October 1983; revision received 22 December 1983; accepted 29 December 1983)
Hakki AH, Iskandrian AS, Colby J. Similarity between men and women in the manifestation of myocardial ischemia during exercise. Int J Cardiol1984; 5:721-726. We assessed the effect of gender on the electrocardiographic changes and thallium24M myocardial perfusion during exercise in patients with coronary artery disease. Eighty-nine patients with coronary artery disease (50% or greater diameter narrowing of one or more major coronary arteries) who had undergone exercise thallium scintigraphy were retrospectively studied. There were 29 women and 60 men. Fifty-six patients had one-vessel disease, 11 patients had two-vessel disease, and 22 patients had three-vessel disease or left main disease. The extent of coronary artery disease was assessed by the Gensini score. There was no difference between men and women in age, medications, number of diseased vessels and the coronary artery disease score. Exercise tolerance was lower, although insignificantly in women compared to men. However, exercise heart rate, double product, and the electrocardiographic response were similar in men and women. Also, both the presence and size of exercise-induced perfusion defects were similar in men and women. Thus, the electrocardiographic response to exercise is not influenced by gender in patients with similar extent of coronary artery disease and comparable manifestations of myocardial ischemia.
Women demonstrate several physiological differences during exercise compared to men [1,2]. The electrocardiographic response to exercise in women has been shown to be different than in men resulting in lower sensitivity and specificity in detecting coronary artery disease [3-51. It has also been suggested that the electrocardiographic responses are similar in men and women if the extent of coronary Reprint requests fo: Abdulmassih S. Iskandrian, MD, Likoff Cardiovascular Institute, University and Hospital, 230 North Broad Street, Philadelphia, PA 19102, U.S.A.
0167-5273/84/$03.00
Q 1984 Elsevier Science Publishers B.V.
Hahnemann
722
artery disease is similar [6,7]. It was assumed in these studies that the incidence of myocardial ischemia during exercise was similar in patients with similar extent of coronary artery disease. However, recent studies using thallium-201 imaging demonstrate a wide variation in the extent of jeopardized myocardium, even among patients with similar extent of disease [8,9]. Thus, in order to evaluate the electrocardiographic response to exercise in men and women with coronary artery disease, the similarity in the extent of coronary disease and the size of perfusion defects during exercise must be addressed. The purpose of this study was to compare the results of exercise electrocardiography in relation to thallium-201 scintigraphy in women and men with coronary artery disease.
Methods We reviewed our record and identified 89 patients with coronary artery disease (50% or greater diameter narrowing of one or more major vessels who had had exercise thallium scintigraphy and cardiac catheterization within six months of each other. There were 60 men and 29 women (mean age 54 years; range 34-75). Most of the women included in this study were part of a previous publication [lo]. The patients were consecutively studied. Patients with Q-wave myocardial infarction, valvular heart disease or previous coronary bypass surgery were excluded. Exercise Testing All patients were exercised in the fasting state in accordance with the standard Bruce protocol for treadmill exercise testing. The end-points of exercise were severe angina pectoris (with or without ST-segment depression), excessive fatigue, leg weakness, dyspnea, hypotension or frequent premature ventricular complexes. The exercise electrocardiograms were interpreted as positive, negative, or inconclusive according to previously described methods from this laboratory [ll]. The exercise electrocardiograms were evaluated by two independent observers without prior knowledge of the other test results. ThaIlium-201 Imaging At peak exercise, two millicuries of thallium-201 were injected intravenously and flushed with dextrose and water. The patient was then allowed to continue exercising for 1 min more. Five to 10 min after the injection, images were obtained in three projections. The techniques for imaging and data processing, and interobserver and intraobserver variability in interpreting the scintigrams have been described in detail [9-111. Redistribution images were performed 4 hr after the initial scans and showed reperfusion suggestive of myocardial ischemia. In addition to the qualitative interpretation of the images, the perimeter of the defects was measured and expressed as a percentage of the total perimeter of the left ventricular image in that projection, excluding the value plane. The average size of the defect was obtained from the three projections [9].
723
Cardiac Catheterization
and Angiography
Each patient underwent left and right heart catheterization, left ventriculography and coronary arteriography by standard techniques. Left ventriculography was performed in the 30” right anterior oblique projection. Significant coronary artery disease was considered to be present if there was 50% or greater diameter narrowing of one or more major coronary arteries. In addition, we quantitated the extent of coronary artery disease using the scoring system of Gensini [12]. The score takes into consideration the severity of stenosis, the cumulative effects of multiple obstructions, the significance of their location, the modifying influence of collaterals and the size and quality of distal vessels. The score may vary between zero and 192. The results of the cardiac catheterization were reviewed by two experienced angiographers without knowledge of the other test results. Statist&l
Analysis
Statistical analysis was performed using the analysis of variance. Significance of difference between the discrete variables was performed using a two-tailed Fisher’s exact test. A probability (P) value < 0.05 was considered significant. Results were expressed as the mean f. standard deviation (SD) when applicable.
Results The clinical, electrocardiographic, exercise and scintigraphic data are given in Table 1. There are no significant differences between men and women with coronary artery disease with regard to age and medications. Men exercised for a slightly but insignificantly longer duration than women (7.2 + 3.5 min vs. 5.8 k 3.1 min). Twelve women (41%) and 28 men (47%) complained of angina during exercise (Fig. 1). Inconclusive exercise electrocardiograms were slightly but insignificantly more frequent among women than men (52% vs. 35% respectively). Inconclusive exercise electrocardiograms occurred in 45% of patients with one-vessel disease and in 33% of patients with multivessel disease (P = NS). There were 53 patients with conclusive electrocardiograms (either positive or negative), 39 men and 14 women. There was no significant difference in occurrence of positive exercise electrocardiograms between men and women in patients with conclusive results. Similarly, the incidence of abnormal thallium-201 myocardial images was similar in men and women. The size of the perfusion defect on thallium images was similar in men and women. Positive exercise electrocardiograms were present in 8 of 22 (36%) women with abnormal thallium-201 images, compared to 26 of 52 (50%) men (P=NS). Thus, the occurrence of myocardial ischemia indicated by exercise-induced angina or abnormal thallium image was similar between men and women (see Fig. 1).
124 TABLE Pertinent
1 data in men and women with coronary
artery
disease.
Women (a = 29) No.(X) Age (years) Digitalis therapy Beta blockers Calcium blockers Ex duration (mm) Ex HR (beats/mm) Ex SBP (mm Hg) Ex DP (mm Hg.minml/lO1) Ex angina Conclusive Ex ECG Positive Negative Inconclusive Ex ECG Abnormal TL Perfusion defect size (fg) Coronary artery disease score Coronary artery disease l-VD 2-VD 3-VD or LM LVEF (P)
Men(n=60)
Mean + SD 55
No. (%)
_+I0
Mean + SD 53
4 (14) 18 (62)
_+ 8
5 (8) 29 (48)
4 (14)
4 (7) 5.8* 3.1 135 rfr26 161 *28 21.8* 6.2
7.2? 3.5 135 +23 162 *29 22.1* 6.3
12 (41) 10/14 4/14 15 22
P value
28 (47)
(71) (29) (52) (76)
32/39 7/39 21 52 23 27
(82) (18) (35) (87)
+18 *31
24 24
19 (66)
3-l (62)
2 (7) 8 (28)
9 (15) 14 (23) 63
*13
61
NS NS NS NS 0.08 NS NS NS NS
*16 *19
NS NS NS NS NS NS
?12
NS NS NS NS
DP = double product (heart rate times systolic blood pressure); ECG = electrocardiogram; Ex = exercise; HR = heart rate; LVEF = left ventricular ejection fraction; LM = left main disease; Ml = myocardial infarction; n = number of patients; NS = not significant; SBP = systolic blood pressure; SD = standard deviation; TL = thallium-201 images; VD = vessel disease
1
I
Ex ECG inconclusive
E .i s P
75
= 50 E ti ii P 25
Woman
Ex
Men
ECG
Womon
Man
Abnormal Ex TL
Womon
Man
Ex Induced Angina
Fig. 1. Exercise results in women and men. ECG = electrocardiogram; patients; TL = thallium-201 myocardial scintigraphy.
Ex = exercise;
n = number
of
Similarly, there was no difference between men and diseased vessels or the coronary artery disease score.
women
in the number
of
Discussion This study demonstrates that men and women with coronary artery disease manifest similar exercise electrocardiographic changes when the extent of coronary disease as well as myocardial perfusion during exercise were similar. Men had slightly although insignificantly better exercise capacity than women which may be related to similar physiological differences between normal men and women. The extent of coronary artery disease is an important factor that determines the results of exercise electrocardiography [13-151. False negative results are more common in patients with one-vessel disease than in patients with multivessel disease. Since the hemodynamic significance of coronary stenosis depends on the number of diseased vessels, the site and severity of stenosis and effect of collaterals, we quantitated the extent of disease by a scoring system that takes these factors into consideration. The coronary artery disease score was similar in men and women. The incidence of positive and negative exercise electrocardiograms was similar in men and women. Our findings are in agreement with the reported sensitivity of multiple lead exercise electrocardiography [7]. Den-y et al. [4] reported on the diagnostic value of exercise electrocardiography in 178 patients who had undergone coronary arteriography. Of the 20 women with coronary artery disease in their study, 16 (80%) had positive exercise electrocardiograms. Linhart et al. [16] performed maximal treadmill exercise testing in 98 women, 24 with and 74 without coronary artery disease. They found that the exercise electrocardiographic response in women was similar to men when patients with resting electrocardiographic abnormalities were excluded. Weiner et al. [6] found similar exercise electrocardiographic changes in 870 men and women matched for age, previous infarction, and number of diseased vessels. It is not known, however, whether manifestations of myocardial ischemia were similar in men and women in the latter study. Since the extent of ischemic myocardium varies considerably among patients with coronary artery disease, the similarity in the number of diseased vessels may not be sufficient. Since the hypothesis being tested was the electrocardiographic response to exercise in men and women, the use of an independent method to detect myocardial ischemia such as thallium-201 imaging as done in our study seems appropriate. The current study confirms the similarity in exercise electrocardiographic response in men and women with similar extent of coronary disease and myocardial perfusion during exercise. Clinical Implications The electrocardiographic response to exercise is similar in men and women with comparable manifestations of myocardial ischemia (exercise-induced angina pectoris or exercise-induced perfusion defect) and similar extent of coronary artery disease. The gender, per se, does not influence the exercise test results. Any differences
126
between the sexes should be explained by the difference in extent of coronary artery disease or other factors that affect myocardial oxygen supply/demand ratio. The similarity of exercise testing parameters among men and women in this study does not apply to unselected population of men and women undergoing diagnostic exercise testing, since the incidence of coronary disease is not similar in men and women.
Acknowledgments The authors thank Wanda preparing the manuscript.
Klein
and
Eric M. Umile
for their
assistance
in
References 1 Blomqvist 2 3
4
5
6
7 8 9 10
11
12 13
14
15 16
CG. Use of exercise testing for diagnostic and functional evaluation of patients with arteriosclerotic heart disease. Circulation 1971;44:1120-1133. Astrand I. Aerobic work capacity, its relationship to age, sex. and other factors. Circ Res 1967;2O(suppl I):211-217. Sketch MH, Mohiuddin SM. Lynch JD. Zencka AE, Runco V. Significant sex differences in the correlation of electrocardiographic exercise testing and coronary arteriograms. Am J Cardiol 1975;36:169-173. Detry J-MR. Kapita BM, Cosyns J, Sottiaux B, Brasseur LA, Rousseau MI. Diagnostic value of history and maximal exercise electrocardiography in men and women suspected of coronary artery disease. Circulation 1977;56:756-761. Weiner DA, Ryan TJ, McCabe CH, et al. Exercise stress testing: correlations among history of angina. ST-segment response and prevalence of coronary artery disease in the coronary artery surgery study (CASS). N Engl J Med 1979;301:230-235. Weiner DA, McCabe CH, Fisher LD, Chaitman BR. Ryan TJ. Similar rates of false positive and false negative exercise tests in matched males and females (CASS) (abstract). Circulation 1978;58(suppl 11):140. Guiteras Val P, Chaitman BR, Waters DD, et al. Diagnostic accuracy of exercise ECG lead systems in clinical subsets of women. Circulation 1982;65:1465-1474. Iskandrian AS, Hakki AH. Kane SA, Segal BL. Assessment of jeopardized myocardium in patients with multivessel disease. Am Heart J (in press). Iskandrian AS, Lichtenberg R, Segal BL, et al. Assessment of jeopardized myocardium in patients with one-vessel disease. Circulation 1982;65:242-247. Friedman TD, Greene AC, Iskandrian AS, Hakki AH, Kane SA, Segal BL. Exercise thallium-201 myocardial scintigraphy in women: correlation with coronary arteriography. Am J Cardiol 1982;49:1632-1637. Iskandrian AS, Wasserman LA, Anderson GJ, Hakki HA, Segal BL. Kane SA. Merits of stress thallium-201 myocardial perfusion imaging in patients with inconclusive exercise electrocardiograms: correlation with coronary angiograms. Am J Cardiol 1980;46:553-558. Gensini GC. Coronary arteriography. Mount Kisco, NY: Futura, 1975;261. Hakki AH, DePace NL, Colby J, Iskandrian AS. Implications of normal exercise electrocardiograms in patients with angiographically documented coronary artery disease: correlation with left ventricular function and myocardial perfusion. Am J Med 1983;75:439-444 McCarthy DM, Sciacca RR, Blood DK, Cannon PJ. Discriminant function analysis using thallium-201 scintiscans and exercise stress test variables to predict the presence and extent of coronary artery disease. Am J Cardiol 1982;1917-1926. Goldschlager N, Seizer A, Cohn K. Treadmill stress tests as indicators of presence and severity of coronary artery disease. Ann Intern Med 1976;85:277-286. Linhart JW, Laws JG, Satinsky JD. Maximum treadmill exercise electrocardiography in female patients. Circulation 1974;54:1173-1178.
721
IJC 00141
Similarity between women and men in manifestation of myocardial ischemia during exercise A-Hamid Hakki, Abdulmassih S. Iskandrian and Jay Colby Likoff Cardiovascular Institute of Hahnemann University and Hospital, Philadelphia, Pennsylvania (Received 14 October 1983; revision received 22 December 1983; accepted 29 December 1983)
Hakki AH, Iskandrian AS, Colby J. Similarity between men and women in the manifestation of myocardial ischemia during exercise. Int J Cardiol1984; 5:721-726. We assessed the effect of gender on the electrocardiographic changes and thallium24M myocardial perfusion during exercise in patients with coronary artery disease. Eighty-nine patients with coronary artery disease (50% or greater diameter narrowing of one or more major coronary arteries) who had undergone exercise thallium scintigraphy were retrospectively studied. There were 29 women and 60 men. Fifty-six patients had one-vessel disease, 11 patients had two-vessel disease, and 22 patients had three-vessel disease or left main disease. The extent of coronary artery disease was assessed by the Gensini score. There was no difference between men and women in age, medications, number of diseased vessels and the coronary artery disease score. Exercise tolerance was lower, although insignificantly in women compared to men. However, exercise heart rate, double product, and the electrocardiographic response were similar in men and women. Also, both the presence and size of exercise-induced perfusion defects were similar in men and women. Thus, the electrocardiographic response to exercise is not influenced by gender in patients with similar extent of coronary artery disease and comparable manifestations of myocardial ischemia.
Women demonstrate several physiological differences during exercise compared to men [1,2]. The electrocardiographic response to exercise in women has been shown to be different than in men resulting in lower sensitivity and specificity in detecting coronary artery disease [3-51. It has also been suggested that the electrocardiographic responses are similar in men and women if the extent of coronary Reprint requests fo: Abdulmassih S. Iskandrian, MD, Likoff Cardiovascular Institute, University and Hospital, 230 North Broad Street, Philadelphia, PA 19102, U.S.A.
0167-5273/84/$03.00
Q 1984 Elsevier Science Publishers B.V.
Hahnemann
722
artery disease is similar [6,7]. It was assumed in these studies that the incidence of myocardial ischemia during exercise was similar in patients with similar extent of coronary artery disease. However, recent studies using thallium-201 imaging demonstrate a wide variation in the extent of jeopardized myocardium, even among patients with similar extent of disease [8,9]. Thus, in order to evaluate the electrocardiographic response to exercise in men and women with coronary artery disease, the similarity in the extent of coronary disease and the size of perfusion defects during exercise must be addressed. The purpose of this study was to compare the results of exercise electrocardiography in relation to thallium-201 scintigraphy in women and men with coronary artery disease.
Methods We reviewed our record and identified 89 patients with coronary artery disease (50% or greater diameter narrowing of one or more major vessels who had had exercise thallium scintigraphy and cardiac catheterization within six months of each other. There were 60 men and 29 women (mean age 54 years; range 34-75). Most of the women included in this study were part of a previous publication [lo]. The patients were consecutively studied. Patients with Q-wave myocardial infarction, valvular heart disease or previous coronary bypass surgery were excluded. Exercise Testing All patients were exercised in the fasting state in accordance with the standard Bruce protocol for treadmill exercise testing. The end-points of exercise were severe angina pectoris (with or without ST-segment depression), excessive fatigue, leg weakness, dyspnea, hypotension or frequent premature ventricular complexes. The exercise electrocardiograms were interpreted as positive, negative, or inconclusive according to previously described methods from this laboratory [ll]. The exercise electrocardiograms were evaluated by two independent observers without prior knowledge of the other test results. ThaIlium-201 Imaging At peak exercise, two millicuries of thallium-201 were injected intravenously and flushed with dextrose and water. The patient was then allowed to continue exercising for 1 min more. Five to 10 min after the injection, images were obtained in three projections. The techniques for imaging and data processing, and interobserver and intraobserver variability in interpreting the scintigrams have been described in detail [9-111. Redistribution images were performed 4 hr after the initial scans and showed reperfusion suggestive of myocardial ischemia. In addition to the qualitative interpretation of the images, the perimeter of the defects was measured and expressed as a percentage of the total perimeter of the left ventricular image in that projection, excluding the value plane. The average size of the defect was obtained from the three projections [9].
723
Cardiac Catheterization
and Angiography
Each patient underwent left and right heart catheterization, left ventriculography and coronary arteriography by standard techniques. Left ventriculography was performed in the 30” right anterior oblique projection. Significant coronary artery disease was considered to be present if there was 50% or greater diameter narrowing of one or more major coronary arteries. In addition, we quantitated the extent of coronary artery disease using the scoring system of Gensini [12]. The score takes into consideration the severity of stenosis, the cumulative effects of multiple obstructions, the significance of their location, the modifying influence of collaterals and the size and quality of distal vessels. The score may vary between zero and 192. The results of the cardiac catheterization were reviewed by two experienced angiographers without knowledge of the other test results. Statist&l
Analysis
Statistical analysis was performed using the analysis of variance. Significance of difference between the discrete variables was performed using a two-tailed Fisher’s exact test. A probability (P) value < 0.05 was considered significant. Results were expressed as the mean f. standard deviation (SD) when applicable.
Results The clinical, electrocardiographic, exercise and scintigraphic data are given in Table 1. There are no significant differences between men and women with coronary artery disease with regard to age and medications. Men exercised for a slightly but insignificantly longer duration than women (7.2 + 3.5 min vs. 5.8 k 3.1 min). Twelve women (41%) and 28 men (47%) complained of angina during exercise (Fig. 1). Inconclusive exercise electrocardiograms were slightly but insignificantly more frequent among women than men (52% vs. 35% respectively). Inconclusive exercise electrocardiograms occurred in 45% of patients with one-vessel disease and in 33% of patients with multivessel disease (P = NS). There were 53 patients with conclusive electrocardiograms (either positive or negative), 39 men and 14 women. There was no significant difference in occurrence of positive exercise electrocardiograms between men and women in patients with conclusive results. Similarly, the incidence of abnormal thallium-201 myocardial images was similar in men and women. The size of the perfusion defect on thallium images was similar in men and women. Positive exercise electrocardiograms were present in 8 of 22 (36%) women with abnormal thallium-201 images, compared to 26 of 52 (50%) men (P=NS). Thus, the occurrence of myocardial ischemia indicated by exercise-induced angina or abnormal thallium image was similar between men and women (see Fig. 1).
124 TABLE Pertinent
1 data in men and women with coronary
artery
disease.
Women (a = 29) No.(X) Age (years) Digitalis therapy Beta blockers Calcium blockers Ex duration (mm) Ex HR (beats/mm) Ex SBP (mm Hg) Ex DP (mm Hg.minml/lO1) Ex angina Conclusive Ex ECG Positive Negative Inconclusive Ex ECG Abnormal TL Perfusion defect size (fg) Coronary artery disease score Coronary artery disease l-VD 2-VD 3-VD or LM LVEF (P)
Men(n=60)
Mean + SD 55
No. (%)
_+I0
Mean + SD 53
4 (14) 18 (62)
_+ 8
5 (8) 29 (48)
4 (14)
4 (7) 5.8* 3.1 135 rfr26 161 *28 21.8* 6.2
7.2? 3.5 135 +23 162 *29 22.1* 6.3
12 (41) 10/14 4/14 15 22
P value
28 (47)
(71) (29) (52) (76)
32/39 7/39 21 52 23 27
(82) (18) (35) (87)
+18 *31
24 24
19 (66)
3-l (62)
2 (7) 8 (28)
9 (15) 14 (23) 63
*13
61
NS NS NS NS 0.08 NS NS NS NS
*16 *19
NS NS NS NS NS NS
?12
NS NS NS NS
DP = double product (heart rate times systolic blood pressure); ECG = electrocardiogram; Ex = exercise; HR = heart rate; LVEF = left ventricular ejection fraction; LM = left main disease; Ml = myocardial infarction; n = number of patients; NS = not significant; SBP = systolic blood pressure; SD = standard deviation; TL = thallium-201 images; VD = vessel disease
1
I
Ex ECG inconclusive
E .i s P
75
= 50 E ti ii P 25
Woman
Ex
Men
ECG
Womon
Man
Abnormal Ex TL
Womon
Man
Ex Induced Angina
Fig. 1. Exercise results in women and men. ECG = electrocardiogram; patients; TL = thallium-201 myocardial scintigraphy.
Ex = exercise;
n = number
of
Similarly, there was no difference between men and diseased vessels or the coronary artery disease score.
women
in the number
of
Discussion This study demonstrates that men and women with coronary artery disease manifest similar exercise electrocardiographic changes when the extent of coronary disease as well as myocardial perfusion during exercise were similar. Men had slightly although insignificantly better exercise capacity than women which may be related to similar physiological differences between normal men and women. The extent of coronary artery disease is an important factor that determines the results of exercise electrocardiography [13-151. False negative results are more common in patients with one-vessel disease than in patients with multivessel disease. Since the hemodynamic significance of coronary stenosis depends on the number of diseased vessels, the site and severity of stenosis and effect of collaterals, we quantitated the extent of disease by a scoring system that takes these factors into consideration. The coronary artery disease score was similar in men and women. The incidence of positive and negative exercise electrocardiograms was similar in men and women. Our findings are in agreement with the reported sensitivity of multiple lead exercise electrocardiography [7]. Den-y et al. [4] reported on the diagnostic value of exercise electrocardiography in 178 patients who had undergone coronary arteriography. Of the 20 women with coronary artery disease in their study, 16 (80%) had positive exercise electrocardiograms. Linhart et al. [16] performed maximal treadmill exercise testing in 98 women, 24 with and 74 without coronary artery disease. They found that the exercise electrocardiographic response in women was similar to men when patients with resting electrocardiographic abnormalities were excluded. Weiner et al. [6] found similar exercise electrocardiographic changes in 870 men and women matched for age, previous infarction, and number of diseased vessels. It is not known, however, whether manifestations of myocardial ischemia were similar in men and women in the latter study. Since the extent of ischemic myocardium varies considerably among patients with coronary artery disease, the similarity in the number of diseased vessels may not be sufficient. Since the hypothesis being tested was the electrocardiographic response to exercise in men and women, the use of an independent method to detect myocardial ischemia such as thallium-201 imaging as done in our study seems appropriate. The current study confirms the similarity in exercise electrocardiographic response in men and women with similar extent of coronary disease and myocardial perfusion during exercise. Clinical Implications The electrocardiographic response to exercise is similar in men and women with comparable manifestations of myocardial ischemia (exercise-induced angina pectoris or exercise-induced perfusion defect) and similar extent of coronary artery disease. The gender, per se, does not influence the exercise test results. Any differences
126
between the sexes should be explained by the difference in extent of coronary artery disease or other factors that affect myocardial oxygen supply/demand ratio. The similarity of exercise testing parameters among men and women in this study does not apply to unselected population of men and women undergoing diagnostic exercise testing, since the incidence of coronary disease is not similar in men and women.
Acknowledgments The authors thank Wanda preparing the manuscript.
Klein
and
Eric M. Umile
for their
assistance
in
References 1 Blomqvist 2 3
4
5
6
7 8 9 10
11
12 13
14
15 16
CG. Use of exercise testing for diagnostic and functional evaluation of patients with arteriosclerotic heart disease. Circulation 1971;44:1120-1133. Astrand I. Aerobic work capacity, its relationship to age, sex. and other factors. Circ Res 1967;2O(suppl I):211-217. Sketch MH, Mohiuddin SM. Lynch JD. Zencka AE, Runco V. Significant sex differences in the correlation of electrocardiographic exercise testing and coronary arteriograms. Am J Cardiol 1975;36:169-173. Detry J-MR. Kapita BM, Cosyns J, Sottiaux B, Brasseur LA, Rousseau MI. Diagnostic value of history and maximal exercise electrocardiography in men and women suspected of coronary artery disease. Circulation 1977;56:756-761. Weiner DA, Ryan TJ, McCabe CH, et al. Exercise stress testing: correlations among history of angina. ST-segment response and prevalence of coronary artery disease in the coronary artery surgery study (CASS). N Engl J Med 1979;301:230-235. Weiner DA, McCabe CH, Fisher LD, Chaitman BR. Ryan TJ. Similar rates of false positive and false negative exercise tests in matched males and females (CASS) (abstract). Circulation 1978;58(suppl 11):140. Guiteras Val P, Chaitman BR, Waters DD, et al. Diagnostic accuracy of exercise ECG lead systems in clinical subsets of women. Circulation 1982;65:1465-1474. Iskandrian AS, Hakki AH. Kane SA, Segal BL. Assessment of jeopardized myocardium in patients with multivessel disease. Am Heart J (in press). Iskandrian AS, Lichtenberg R, Segal BL, et al. Assessment of jeopardized myocardium in patients with one-vessel disease. Circulation 1982;65:242-247. Friedman TD, Greene AC, Iskandrian AS, Hakki AH, Kane SA, Segal BL. Exercise thallium-201 myocardial scintigraphy in women: correlation with coronary arteriography. Am J Cardiol 1982;49:1632-1637. Iskandrian AS, Wasserman LA, Anderson GJ, Hakki HA, Segal BL. Kane SA. Merits of stress thallium-201 myocardial perfusion imaging in patients with inconclusive exercise electrocardiograms: correlation with coronary angiograms. Am J Cardiol 1980;46:553-558. Gensini GC. Coronary arteriography. Mount Kisco, NY: Futura, 1975;261. Hakki AH, DePace NL, Colby J, Iskandrian AS. Implications of normal exercise electrocardiograms in patients with angiographically documented coronary artery disease: correlation with left ventricular function and myocardial perfusion. Am J Med 1983;75:439-444 McCarthy DM, Sciacca RR, Blood DK, Cannon PJ. Discriminant function analysis using thallium-201 scintiscans and exercise stress test variables to predict the presence and extent of coronary artery disease. Am J Cardiol 1982;1917-1926. Goldschlager N, Seizer A, Cohn K. Treadmill stress tests as indicators of presence and severity of coronary artery disease. Ann Intern Med 1976;85:277-286. Linhart JW, Laws JG, Satinsky JD. Maximum treadmill exercise electrocardiography in female patients. Circulation 1974;54:1173-1178.