The interpretation of electrocardiographic change in treadmill exercise test is difficult when the test is performed in patients with abnormal resting electrocardiography. In patients with primary nagative T wave, normalization of primary negative T wave(pseudonormalization)is not uncommon finding during treadmill exercise test. The mechanism of pseudonormalization is uncertain and the interpretation is difficult. Thus this study was performed to evaluate the diagnostic significance of pseudonormalization during treadmill exercise test.

200 cases who showed primary negative T wave at rest were included in this study. The results were classified as positive, borderline positive, borderline negative, negative, non-diagnostic and pseudonormalization.

Pseudonormalization during treadmill exercise test was oberved in 78(39%) of the 200 cases who had primary negative T wave at rest. Coronary angiography and left ventriculography were performed in 13(mean age 56±7 year, male vs. female 1:2.25) of 78 cases who showed pseudonormalization during exercise. They had no history of acute myocardial infarction and no abnormalities such as abnormal Q wave, left ventricular hypertrophy,bundle branch block,right ventricular hypertrophy and QRS widening above 0.1ms in resting electrocardiography. There were significant stenosis in only 3 cases; 2 cases in left anterior descending coronary artery and 1 case in right coronary artery.

In treadmill exercise tests, pseudonormalization appears as non-specific finding for the diagnosis of ischemic heart disease becuase it is observed in either patients with or without coronary artery stenosis.