Usefulness of Serial Treadmill Exercise Testing in Patients With First Episode of Myocardial Infarction

In order to assess the usefulness of repeated exercise tests for prediction of prognosis in patients with myocardial infarction, serial treadmill exercise testing (4.5 tests/patient during 32 months) was performed on 73 patients with the first attack of acute myocardial infarction. A significant ST depression was observed at the first test in 28 cases (38%). Regardless of the results of the first test, the pressure-rate product (PRP) at the same exercise level decreased significantly at the last test. On the other hand, the time to onset of 1 mm ST depression increased significantly at the last test in those with a positive first test, although the PRP at 1 mm ST depression remained unchanged in most of these cases.A significant reduction of more than 10% of PRP at 1 mm ST depression was demonstrated in 4 patients with multi-vessel disease during the follow-up period.Unstable angina pectoris developed in 2 of these 4 patients with decreased exercise tolerance as well as in 1 patient whose exercise test result changed from negative to positive. The exercise tolerance was unchanged during the follow-up period in 3 patients of reinfarction and 1 patient of sudden death. Thus, the repeated treadmill exercise tests are of value for the prediction of development of unstable angina pectoris, but not for the prediction of sudden death and reinfarction.