Silent myocardial ischemia: II. Prognosis and implications for the clinical assessment of patients with coronary artery disease.

Myocardial ischemia is known to be a strong independent predictor of cardiac events. New data suggest that the presence of silent ischemia, like symptomatic ischemia, is indicative of an increased risk of future cardiac events. Ordinarily, patients with suspected or known coronary artery disease are evaluated first for the presence of myocardial ischemia by performing exercise ECG, used as a test of both diagnosis and prognosis. In those patients who have an "intermediate" probability of cardiac event after exercise ECG, prognostic assessment may be enhanced, by using either radionuclide stress testing, to assess the extent and severity of potentially inducible ischemia, or ambulatory ECG, to assess the frequency and duration of spontaneously occurring ischemia. The indications for testing and type of test to be used are highly dependent on a number of clinical factors, not the least of which are the nature of the population to be evaluated and the exercise ECG response. We have proposed an overall approach for prognostic testing that considers the potential strengths and limitations of each form of testing. This potential approach now requires prospective evaluation.