Association of ST segment depression 5 min after exercise testing with severity of coronary artery disease

Objective: To determine the association of prolonged ST segment depression after an exercise test with severity of coronary artery disease. Methods: A cross sectional study of 100 consecutive patients referred to the cardiology laboratory for stress myocardial perfusion imaging (MPI) conducted between April-August 2008. All selected patients were monitored until their ST segment depression was recovered to baseline. ST segment recovery time was categorized into less and more than 5 minutes. Subsequent gated SPECT-MPI was performed and stratified according to severity of perfusion defect. Association was determined between post exercise ST segment depression recovery time ( 5 minutes and 5 minutes) and severity of perfusion defect on MPI. Results: The mean age of the patients was 57.12 ± 9.0 years. The results showed statistically insignificant association (p 0.05) between ST segment recovery time of 5 minutes and 5 minutes with low, intermediate or high risk MPI. Conclusion: Our findings suggest that the commonly used cut-off levels used in literature for prolonged, post exercise ST segment depression ( 5 minutes into recovery phase) does not correlate with severity of ischaemia based on MPI results.