You may not have the more accurate test. Dx'd CAD is greatly increased by performing a nuclear perfusion study in conjunction with the stress test. A radioactive substance called thallium (or a similar substance called sestamibi or Cardiolite) is injected into a vein during exercise. The thallium collects in the parts of the heart that have good blood flow. Pictures of the heart are taken with a special camera that can image the radioactivity of the thallium. From these pictures, portions of the heart that are not receiving good blood flow (because of blockage in the coronary arteries) can be identified. The thallium study greatly increases the accuracy of the exercise study in diagnosing coronary artery disease.
Another procedure uses echocardiograms in conjunction with stress tests. An echo test is made at rest, and then with exercise, looking for changes in the function of the heart muscle during exercise. Deterioration in muscle function during exercise can indicate coronary artery disease.
False positive and false negative studies can significantly limit the usefulness of the stress test in many patients. By adding a nuclear perfusion study to the stress test, this limitation is minimized, and the diagnostic capacity of the stress test is greatly improved