Coronary Artery Disease Screening Tests (CAD) (cont.)
Exercise Cardiac Stress Test (Treadmill Stress Test)
Exercise cardiac stress testing (ECST) is the most widely used
cardiac stress test. The patient exercises on a treadmill according
to a standardized protocol, with progressive increases in the speed
and elevation of the treadmill (typically changing at three minute
intervals). During the ECST, the patient's electrocardiogram (EKG),
heart rate, heart rhythm, and blood pressure are continuously
monitored. If a coronary arterial blockage results in decreased blood
flow to a part of the heart during exercise, certain changes may be
observed in the EKG, as well as in the response of the heart rate and
blood pressure.
The accuracy of the ECST in predicting significant CAD is variable,
depending in part on the "pre-test likelihood" of CAD (also known as
Bayes' theorem). In a patient at high risk for CAD (e.g.: advanced
age, multiple coronary risk factors), an abnormal ECST is very
predictive of the presence of CAD (over 90% accurate). However, a
relatively normal ECST may not reflect the absence of significant
disease in a patient with the same risk factors. Conversely, in a low-
risk patient, a normal ECST is very predictive of the absence of
significant CAD (over 90% accurate), but an abnormal test may not
reflect the true presence of CAD (so-called "false-positive ECST").
The ECST may either miss the presence of significant CAD, or be a
false-positive test, due to a variety of cardiac circumstances, which
may include:
- An abnormal EKG at rest, which may be due to abnormal serum
electrolytes, abnormal cardiac electrical conduction, or certain
medications, such as digitalis;
- Heart conditions not related to CAD, such as mitral valve
prolapse or hypertrophy (increased size) of the heart; or
- An inadequate increase in the heart rate and/or blood pressure
during exercise.
What if the initial ECST does not clarify the diagnosis?
When the doctor determines that the results of the ECST do not
accurately reflect the presence or absence of significant CAD,
additional tests are often used to clarify the condition. These
additional options include radionucleide isotope injection and
ultrasound of the heart (stress echocardiography) during the stress
test.
Next: Radionucleide Stress Test »
- dipyridamole-injection, Persantine IV - Consumer information about the medication DIPYRIDAMOLE - INJECTION (Persantine IV), includes side effects, drug interactions, recommended dosages, and storage information. Read more about the prescription drug DIPYRIDAMOLE - INJECTION.
- Echocardiogram - Information on Echocardiogram including why you would need one, the types of echocardiograms, how to prepare and what to expect.
- Heart Attack - Overview on heart attack (myocardial infarction) and heart attack symptoms including jaw pain, headache, shortness of breath, nausea, vomiting, heartburn, sweating, and more.
Latest Medical News
Heart RSS