Electrocardiographic exercise test in patients with abnormal T waves at rest.

Summary The results of submaximal ECG exercise test were evaluated in six leads recorded simultaneously in two groups of patients with T-wave abnormalities in one or more of Leads I, II, and V 4–6 . Group I included 185 patients with documented ischemic heart disease (IHD) and Group II 28 patients in whom IHD appeared unlikely. The test was positive in 88 per cent of patients in Group I and in 4 per cent of patients in Group II. In the majority of patients in both groups the T wave either did not change or became more positive or less negative after exercise. The pattern of exercise-induced T-wave changes was similar in patients with and without IHD, and was influenced predominantly by the physiologic effects of exercise. T-wave normalization after exercise occurred frequently in patients with and without IHD, and in patients with positive and negative exercise tests. Our results suggest that T-wave abnormalities, not caused by hypertrophy, conduction disturbances, drugs, or electrolyte imbalance, do not modify the results of submaximal ECG stress test, and that behavior of T wave after exercise does not alter the interpretation of the postexercise ECG. The independent behavior of the S-T segment and T wave after exercise is consistent with the theory that the S-T segment and the T wave are generated by different components of the ventricular action potential.