Clinical Investigations Assessment of ST-T wave Abnormalities on the Baseline Resting Electrocardiography by Exercise 201-TI Single Photon Computerized Tomography (SPECT)

The association of ST-T wave abnormalities on the baseline resting electrocardiography (ECG) with the severity of coronary artery disease (CAD) and increased risk of death from CAD suggest increased ischemia in these patients. To investigate this, 100 consequtive patients were studied by exercise TI-201 Single Photon Computerized Tomography (SPECT). Patients were divided into 2 groups according to the presence (group 1, n=38) or absence (Group 2, n=62) of ST-T wave abnormalities on their resting ECGs. There was no difference between the two groups with respect to age, gender, previous myocardial infarction and coronary artery bypass surgery. The double product (SBPxHR) and workload (METS) achieved were also comparable between the 2 groups. Exercise-induced ST segment depression was found to be significantly more frequent (p<0.001) in group 1,whereas exercise-induced chest pain was similar between the 2 groups. The total number of segments with perfusion defects were significantly higher in group 1 compared to group 2 (p<0.001). In addition, redistribution occured more frequently (p<0.001) and the number of segments with reversible perfusion defects were significantly higher in group 1 compared to group 2 (p<0.001) There was no significant difference in terms of persistent defects between the two groups. These data suggest that incrensed ischemia may be the underlying pathology with resting ST-T wave abnormalities and account for the poor prognosis in these patients.