Differentiation of false- from true-positive ECG responses to exercise stress by thallium 201 perfusion imaging.

false-positive and true-positive ECG responses to exercise stress. Thirty-five patients referred for coronary angiography because of an exercise test interpreted as positive for ischemic ST segment changes (1.0 mm or more reversible horizontal or downsloping ST depression), but who were asymptomatic or had a history of atypical chest pain, underwent repeated exercise testing in conjunction with 201Tl perfusion imaging. All patients received 1.5 mCi of 20’Tl at maximal exercise, and imaging began five minutes after exercise.