Rest and exercise electrocardiograms and radionuclides in patients presenting for cardiac rehabilitation

The rest and exercise ECG, ²⁰¹thallium myocardial scintigram (²⁰¹T1), and radionuclide ventriculography are noninvasive procedures which can be used to evaluate myocardial damage and ischemia. To compare these procedures and to obtain baseline information, 85 male patients with coronary heart disease were evaluated prior to beginning an exercise program. Findings at rest included Q waves or bundle branch block in 54%; 47% had ²⁰¹T1 redistribution defects and 33% an abnormal ejection fraction (EF). Of the 39 patients with normal ECGs, 31 had no ²⁰¹T1 defects and only 1 of these 31 (3%) had an abnormal EF. Abnormal EF or ²⁰¹T1 redistribution defects did not occur in patients without a history of myocardial infarction. Abnormal resting EF occurred in 63% of patients with abnormal versus 7% of those with normal ²⁰¹T1 redistribution scans. Exercise test results included an abnormal ST-segment response in 80%, an abnormal EF response in 65%, and a ²⁰¹T1 ischemic defect in 37%. Twenty patients had exercise-induced ST elevation, and this phenomenon was more related to ventricular aneurysms than to ischemia. ²⁰¹Thallium imaging, radionuclide ventriculography, and the ECG provide results regarding myocardial damage that agree by more than chance, while the exercise-induced ST-segment changes did not agree with the radionuclide indications of exercise-induced ischemia.