Relationship between Baseline ECG Abnormalities and Quantitative Perfusion Parameters of Myocardial Perfusion Findings

Background: Coronary Artery Disease (CAD) is one of the major causes of mortality in most countries. Electrocardiography (ECG) and myocardial perfusion imaging (MPI) are non-invasive disgnostic tests for CAD. Finding a relationship between abnormal findings in the baseline ECG and MPI findings can be helpful in better diagnosis of CAD. Materials and Methods: The present study examined ECG of patients who underwent MPI and categorized them into three groups: normal ECG, abnormal ST-T change, and abnormal Q or fragmented QRS. The quantitative and semi-quantitative parameters as well as visual interpretation of MPI were compared among the three groups. Results: Finally, 230 patients entered the study, including 92 patients (40.0%) with normal ECG, 86 patients (37.4%) with ST-T changes and 52 patients (22.6%) with fQRS-Q complex abnormality. In total, 77 patients (33.5%) had positive MPI scan. There were significant differences between the normal and ST-T subgroups with Q-fQRS group for all quantitative and semi-quantitative variables, however, normal and ST-T groups were significantly different only in terms of SSS, SDS and TPDs. Frequency of abnormal MPI was significantly higher in Q-fQRS group. Conclusion: The results of this study showed that myocardial ischemia is more frequent in patients with baseline ST-T ECG changes. In addition, Q-fQRS abnormality is associated with higher rates of both myocardial scar and ischemia in MPI.