Follow-up testing probably should be performed only if decisions about a change in pharmacological management, level of exercise, or revascu- larization will be influenced directly by the test result or if the patient has persistent symptoms despite adequate GDMT. Thus, in the patient with known SIHD, the goal of repeat testing is the assessment of residual ischemic burden after optimization of GDMT or the consideration of revasculariza- tion as a result of failed optimal medical management. Furthermore, to be considered significant, findings should be outside the expected range of variability of test results, which is approximately 5% for stress nuclear MPI,306,366 such that patients move into a higher or lower risk category. Even for high-risk patients, the value of annual exercise testing (or serial exercise testing at alternative intervals) in the absence of a change in symptoms has not been studied adequately. Yearly exercise testing could be useful in patients with SIHD who have .3% risk of mortality per year, because a marked decrease in exercise capacity or a marked increase in ischemic burden can warrant reevaluation of the medical regimen or interventional plan. Examples of such patients are those with a high-risk Duke treadmill score, patients with an EF ,50% and significant CAD in .1 major vessel, patients with diabetes mellitus, and those with multivessel disease who have not undergone CABG. Some data also suggest that ischemic burden might be useful in targeting ischemia-guided revascularization. 