Stress-induced ST elevation with or without concomitant ST depression is predictive of presence, location and amount of myocardial ischemia assessed by myocardial perfusion SPECT, whereas isolated stress-induced ST depression is not

- Maximum and sum of significant ST elevations at stress correlated with SSS score.
- Excellent agreement between location of ST elevation at stress and stress-induced ischemia on MPS.
- Positive predictive value higher for ST elevation at stress than isolated ST depressions at stress.

BackgroundEvaluation of stress-induced ST deviations constitutes a central part when interpreting the findings from an exercise test. The aim of this analysis was to assess the pathophysiologic correlate of stress-induced ST elevation and ST depression with regard to presence, amount and location of myocardial ischemia as assessed by myocardial perfusion SPECT (MPS) in patients with suspected coronary artery disease.Methods and results226 patients who had undergone bicycle stress test in conjunction with MPS were included. Of these, 198 were consecutive patients while 28 patients were included on the basis of having stress-induced ST elevation mentioned in their clinical report. The amount and location of ST changes were related to MPS findings. Summed stress scores (SSS) from MPS images were used to measure the amount of stress-induced ischemia.The positive predictive values for detecting stress-induced ischemia were 28% for the consecutive patients with ST depression and 75% for patients with ST elevation. The maximum and sum of stress-induced ST elevations correlated with SSS (r2 =0.58, p< 0.001 and r2 =0.73, p < 0.001), whereas the maximum and sum of significant ST depressions did not (r2 =0.022, p = 0.08 and r2 =0.024, p = 0.10). The location of ST elevation corresponded to the location of ischemia by MPS (kappa = 1.0), whereas the location of ST depression did not (kappa = 0.20).ConclusionsStress-induced ST elevation, with or without concomitant ST depression, is predictive of the presence, amount and location of myocardial ischemia assessed by MPS, whereas stress-induced ST depression without concomitant ST elevation is not.