EXERCISE TESTING EARLY AFTER MYOCARDIAL-INFARCTION - RISKS AND BENEFITS

Submaximal exercise testing in the early wk following myocardial infarction appears to be safe in selected patient groups. Potential benefits of such testing include promotion of patient self-confidence, determination of post-hospital exercise prescription, detection of arrhythmias and determination of post-hospital prognosis. The practical value of the apparent psychologic benefits and of the exercise prescription information in a patient not participating in formal exercise rehabilitation therapy is unclear. Detection of potentially important arrhythmias appears to be more adequately effected with 24-h ambulatory ECG, and detection of such arrhythmias appears to add relatively little prognostic information to that available from exercise ECG S-T analysis, or from resting radionuclide ejection fraction. Nonetheless, exercise-induced S-T segment depression can provide potentially useful prognostic information regarding morbid or fatal events during the yr after infarction. Recent data suggest that exercise-induced angina and/or S-T segment depression can aid importantly in the noninvasive determination of the anatomic extent of coronary artery disease. The additional benefit of radionuclide cineangiographic determination of left ventricular function during exercise and of 201Tl scintigraphic determination of myocardial perfusion during stress remain to be defined; however, both approaches appear to provide important prognostic information. Despite the potential benefits of exercise testing, in the absence of clinical trials of available therapy in the high-risk patients defined by exercise testing, there remains an ill-defined relationship between the information available from exercise testing and the results of management decisions based on this information.