PHARMACOLOGICAL STRESS TESTING

Pharmacologic stress testing is generally instituted when contraindications to routine exercise stress exist or when the patient is unable to exercise because of debilitating conditions in various forms. These include the following general indications:

Elderly patients with decreased functional capacity and possible CAD
Patients with chronic debilitation and possible CAD
Younger patients with functional impairment due to injury, arthritis, orthopedic problems, peripheral neuropathy, myopathies, or peripheral vascular disease, in which a maximal heart rate is not easily achieved with routine exercise stress testing, usually because of an early onset of fatigue due to musculoskeletal, neurologic, or vascular problems rather than cardiac ischemia
Other cases, including patients taking beta-blockers or other negative chronotropic agents that would inhibit the ability to achieve an adequate heart response to exercise

Some centers prefer to use pharmacologic stress testing in conjunction with echocardiogram, MRI, or CT scanning because it avoids repositioning the patient, which may be necessary during nuclear imaging. Repositioning the patient may give a false-positive pharmacologic stress test result because of different degrees of attenuation of myocardial tissue imaging with changes in the breast positions as seen in women. Various pharmacologic agents are used for cardiovascular stress testing and are usually used in combination with radionuclide isotopes that are taken up by the myocardium during routine testing.