Thallium-201 myocardial imaging in evaluation of asymptomatic individuals with ischaemic ST segment depression on exercise electrocardiogram.

Asymptomatic adults with normal physical examination, normal resting electrocardiogram, and normal routine laboratory evaluation who have a positive exercise electrocardiogram and abnormal exercise thallium-201 myocardial image have a very high probability of angiographically significant coronary artery disease. If, on the other hand, the exercise electrocardiogram is positive for "ischaemic" ST segment changes, but the exercise thallium image is normal, the probability for coronary disease is low. The exercise electrocardiogram combined with thallium-201 myocardial image are safe non-invasive methods which can be performed on an out-patient basis.