Abstract 9819: The Significance of Early Recovery of the ST Segment Depression in the Recovery Period

Abstract

Background Persistence of ST segment depression in recovery signifies a strongly positive ETT, predictive of more ischemia and underlying CAD. It is unclear if early recovery of the ST segment portends a similar prognosis. We sought to determine if persistence of horizontal / down-sloping ST depression into recovery correlates with CAD burden based on myocardial perfusion imaging (MPI). Methods Retrospective analysis of men and women referred for exercise MPI testing was performed. Normal groups were defined as negative ETT (<1mm of ST depression). Those with positive ECG tests were further stratified based on the ST segment at 1 min in recovery. Persistence group was those with >1mm while the Early Recovery group <1mm. Measured MPI variables were summed stress scores (SSS) and high-risk MPI findings. Analysis of variance was used to compare SSS among groups. To assess whether SSS of Early Recovery is no worse than the Normal group, a one-sided 95% confidence limit was calculated for the difference between groups. A non-inferiority margin of -1 was considered clinically acceptable. Results 538 men and 315 women were analyzed. Mean SSS of the Persistence group (7.90 ± 7.69) was significantly different from Early Recovery (4.67 ± 6.18, p<0.001) and Normal (4.78 ± 5.92, p<0.001). Early Recovery was non-inferior to Normals based on SSS (mean difference 0.12, lower 95% CL=-0.66 >-1, p<0.001). Proportion in Early Recovery was similar to Normal but different from Persistence group based on SSS severity (figure). Conclusion Persistence group manifested significantly higher SSS and greater proportion of moderate to high-risk MPI findings when compared to Early Recovery and Normal groups. Furthermore, there was no significant difference in MPI findings between Normal and Early Recovery groups. Early recovery of the ST segment during recovery may represent an underappreciated false positive finding. The results question the accuracy of the ACC/AHA definition of a positive study.