LIMITED VALUE OF STRESS ELECTROCARDIOGRAPHIC CHANGES IN PREDICTING LATE TL-201 REVERSIBILITY - DO ALL PATIENTS NEED REINJECTION

The aim of this study was to assess the relationship between the exerc ise electrocardiogram (EGG) and late thallium-201 ((201)T1) reversibil ity in a series of 72 consecutive patients with undiagnosed chest pain and an initial persistent perfusion defect on conventional stress/4-h redistribution imaging. We wished to establish the diagnostic accurac y of the exercise ECG in predicting the outcome of late (201)T1 revers ibility. All 72 patients, of whom 44 (61%) had had a previous myocardi al infarction (MI), underwent quantitative planar (201)T1 stress-redis tribution imaging followed by resting (201)T1 imaging 1-4 days later. Fifty (69%) patients showed exercise ECG changes during conventional s tress-redistribution imaging, of whom 30 (42%) had a history of previo us MI and 20 (28%) had suspected coronary artery disease (CAD). The ov erall diagnostic accuracy of the exercise ECG in predicting (201)T1 re versibility was 83% (60/72 patients): 75% (21/28 patients) in patients with suspected CAD and 87% (39/44 patients) in patients with previous MI. Only the patients with a previous MI and a negative exercise ECG showed 100% accuracy (n = 14). We conclude that reinjection of (201)T1 might be withheld in patients with a previous MI and a negative exerc ise EGG. For patients with previous MI and a positive exercise EGG, an d for patients with suspected coronary artery disease regardless of th e result of their exercise EGG, reinjection of (201)T1 should be stron gly considered if the redistribution images are abnormal, because of t he suboptimal diagnostic accuracy of the exercise ECG in these patient s.