Exercise and pharmacologic stress testing for prognosis after acute myocardial infarction.

To evaluate patients after acute myocardial infarction (MI), myocardial perfusion imaging provides prognostic parameters that help identify patients at risk for subsequent cardiac events. In addition, myocardial perfusion imaging can be used to identify functionally important residual stenoses and multivessel disease, even in patients who have received thrombolytic therapy. Three parameters of myocardial perfusion imaging emerge as strong predictors of future cardiac events in post-MI patients: (1) presence of transient defects, (2) the number of transient defects and (3) increased radiotracer uptake in the lung. In addition, radionuclide left ventricular ejection fraction (LVEF) is one of the most powerful predictors of subsequent risk for cardiac events, particularly cardiac death and congestive heart failure. Cardiac catheterization, for the most part, does not add to the prognostic value of radionuclide stress testing. Results of myocardial perfusion imaging studies that employ pharmacologic stress instead of submaximal exercise provide strong predictors of prognosis in post-MI patients.