Noninvasive functional tests and myocardial ischemia detection tests

These tests use a gradually increased physical, pharmacological or electrical stress of the heart to induce symptoms, signs, elecrocardiographic changes, or acquisition of characteristic images in individuals with suspected or existing cardiovascular conditions. Most of these tests use the previously mentioned noninvasive cardiac imaging modalities to derive information on cardiac function.

Exercise stress is the preferred modality to stress the heart because it allows a correlation between exertional symptoms and functional parameters such as the myocardial perfusion pattern, ventricular function, and pulmonary artery pressure. Moreover, it provides information on exercise duration, workload achieved, and presence and extent of ischemic electrocardiographic changes, all of which provide important diagnostic and prognostic information. In the case of a functional test where exercise stress cannot be performed, such as those that use cardiac CT or MRI, or in patients who are unable to exercise or achieve adequate levels of exercise, a pharmacologic stress of the heart is used. The most widely used agents for pharmacologic stress testing can be divided into those that act as coronary arteriolar vasodilators (adenosine, dipyridamole, and regadenoson) and adrenergic agents such as dobutamine.

Noninvasive functional tests can be valuable in detecting stress-induced myocardial ischemia, assessing chest pain (angina), and evaluating the outcome of bypass surgery or stent placement. These studies can also help doctors assess the functional capacity of individuals with suspected or already known heart failure and evaluate the severity of valvular heart disease, among other conditions.

Physicians typically order stress tests for patients with:

  • chest pain,
  • unexplained shortness of breath,
  • unexplained arm, neck, back or jaw discomfort,
  • fatigue or weakness,
  • palpitations,
  • dizziness,
  • fainting episodes,
  • valvular heart disease,
  • heart failure.

Among these tests are included: