Exercise-induced ST Segment Change and Coronary Risk Factors in Apparently Healthy Men
Kiyoshi KAWAKUBO, Ryoko YANAGIBORI, Atsuaki GUNJI
Exercise stress test is useful for the early detection of coronary artery disease and is recom mended as a medical clearance test before the initiation of exercise training. However, when ap plied to apparently healthy people, there are many false positive results. It is therefore necessary to determine indications for stress testing, but few data are available in Japan. In this study, we performed exercise stress test in apparently healthy men to investigate the incidence of exercise induced
... segment changes and their relationship to coronary risk factors. The subjects were 2,187 men who underwent symptom-limited exercise stress test at a health promotion center in Tokyo. Those with a history of cardiovascular disease were excluded. They underwent symptom-limited exercise stress test on a treadmill with a modified Bruce protocol or on a cycle ergometer with a ramp protocol (20 watts per minute). Twelve-lead electrocardiogram was recorded every 3min. Cardiologists evaluated the exercise ECG responses, and advised those with abnormal ST segment changes (Group A) to undergo further examinations at a cardiovascular hospital. The results of further examination such as exercise scintigraphy and/or coronary angio graphy were obtained. Twice the number of subjects with normal exercise responses were selected as age-matched controls (Group N) to compare the coronary risk factors between the two groups. Twenty-nine subjects had abnormal ST segment changes (1.33% of the total subjects) (Group A). Their mean age was 57 years (38 to 76). Among these, 27 had ST segment depression and 2 had ST elevation. Among 1,447 subjects under 50 years of age, 5 had abnormal ST segment changes (0.3%), and among 740 subjects over 50 years of age, 24 had abnormal ST segment changes (3.2%). Further cardiovascular examinations were conducted in 23 patients. Eleven sub jects underwent exercise stress scintigraphy and 5 showed abnormal transient perfusion defects. Seven subjects underwent coronary angiography and 4 showed significant one-vessel coronary arterial stenosis. In 3 subjects, antianginal medications were prescribed. In 5 patients, repeated exercise stress test revealed normal results. Exercise duration, peak heart rate, and peak systolic blood pressure did not differ between Group A and Group N. Body mass index and resting systolic blood pressure was significantly higher in Group A than Group N. Resting diastolic pressure, serum total cholesterol, HDL cholesterol, triglyceride, uric acid, and smoking habit did not differ between the two groups. The number of coronary risk factors did not differ between the two groups. Those with more than 2 risk factors were 41.4% in Group A and 29.3% in Group N (p =0.26). In conclusion, exercise stress test as a screening procedure should be applied to healthy men over 50 years of age.