Moderate to severe abnormalities, such as abnormal wall motion in $4 segments or multivessel abnormali- ties, indicate an increased risk (range: 6- to 10-fold) over that of patients with a normal stress imaging Nonetheless, the current literature with regard to exercise nuclear MPI or exercise echocardiography should be clarified in several ways. Although a normal exercise nuclear MPI or exercise echocardiogram usually is associated with a low annual risk of cardiac death or AMI, the negative predictive value is reduced among patients with a higher pretest likeli- hood of CAD.111,115,279,284,305,306,310,313,314,323 328,330 Further- more, although trials have shown that imaging is useful to detect ischemia and guide intervention in patients with SIHD and that a reduction in ischemia by stress nuclear MPI is associated with an observed (unadjusted) event-free sur- vival,306,333 there is no trial evidence comparing the effective- ness of a strategy of imaging testing for risk stratification versus a strategy of nontesting in patients with SIHD. 3.2.2.6. Dobutamine Stress Echocardiography and Pharmacological Stress Nuclear MPI In one third to one half of patients who undergo risk assessment, exercise stress is not recommended because of an inability to exercise or an abnormal ECG. Similar to exercise echocardiography, multiple large single-center reports have shown that dobutamine stress echocardiography accurately classifies patients into high-risk and very-low-risk groups. 