Cardiovascular Stress Testing: A Description of the Various Types of Stress Tests and Indications for Their Use

Abstract

To describe the various types of stress tests and to provide guidelines for selecting a specific test for an individual patient. Myocardial perfusion imaging, radionuclide angiography, stress echocardiography, and cardiopulmonary exercise testing are described. The advantages and limitations of these techniques are reviewed and compared with those of standard treadmill exercise testing. The agents used for pharmacologic stress testing are discussed. Standard treadmill exercise testing is widely available and is less expensive than the imaging techniques. It is most accurate in patients with normal findings on a resting electrocardiogram who are not taking digoxin. In these patients, standard exercise electrocardiography is almost as accurate as the exercise imaging modalities for identifying those with left main or three-vessel coronary artery disease. Advantages of the stress imaging modalities in comparison with standard exercise electrocardiography include greater accuracy when the resting electrocardiogram shows abnormal findings, higher sensitivity, ability to localize and characterize the extent of myocardial ischemia, and direct measurement of other variables such as left ventricular function. These techniques must be performed carefully in experienced laboratories in order to provide accurate information. Published data are scant that directly compare one technique with another in the same set of patients. The nuclear cardiology techniques have been well validated for detecting left main and three-vessel coronary artery disease and for assessing prognosis. Myocardial perfusion imaging has been well validated for detecting ischemia in patients with abnormal left ventricular function at rest. In comparison with the nuclear cardiology techniques, stress echocardiography is less expensive and provides more ancillary information but has not been as well validated for assessment of severe coronary artery disease or prognosis. Cardiopulmonary exercise testing can be useful in selecting patients for cardiac transplantation and in assessing exertional dyspnea in selected patients. The most common application of pharmacologic stress testing is preoperative risk assessment of patients undergoing noncardiac operations. Pharmacologic stress testing should usually be reversed for patients who are unable to exercise adequately. Most patients with normal findings on a resting electrocardiogram who are not taking digoxin should undergo standard treadmill exercise testing for diagnostic and prognostic purposes. Most patients with abnormal findings on a resting electrocardiogram should undergo one of the stress imaging techniques. Selecting a specific stress imaging techniques. should depend primarily on local expertise with the various techniques and secondarily on the strengths and limitations of the techniques as they relate to the individual patient.