Cardiovascular disease is always a challenge to underwrite and find the right risk classification for. The number of deaths attributed to cardiovascular disease is greater than the number resulting from all other leading causes of death in the United States combined. That includes cancer, accidents, hepatitis C, HIV, etc. Which cardiac testing gives us the most accurate results and ones that make us most confident in underwriting a risk?
The most widely used test for the detection of CAD is the treadmill or stress EKG. A person is exercised to reach a heart rate of 85% of the predicted heart rate for build and age (called a Bruce protocol) and the EKG tracing, which is continually running, is looked at for changes. These changes can be in the shape of the complexes (a lack of oxygen to the heart can cause depression of cardiac complexes), changes in rhythm (a non-regular rhythm can indicate serious underlying disease), and also the duration of time a person can complete on a treadmill. While no one is looking for the next tri-athlete, a heart that can only support a few minutes without the induction of pain, arrhythmia, or sudden acceleration to maximal heart rate are signs of a heart which may have problems in the immediate future.
Stress echocardiography also requires exercise testing, but instead of an EKG printout, imaging for evaluation of heart wall function is used. The stress echo can visualize areas of the heart that do contract efficiently with good accuracy, and also allow visualization of the valves within the heart that direct blood from one chamber to another and out to the body. It is more exact in terms of localizing heart function and looking at structures within the heart.
Stress MPI and SPECT testing are more exact in their measurement and location of heart dysfunction. Individual wall motion and the contraction of the largest, most powerful heart chamber (the left ventricle) can be evaluated simultaneously. A radionuclide agent is used to sharpen the images obtained. The information used can be used to stratify risks associated with heart muscle dysfunction. It is not used as a first step because it is expensive, time consuming, requires ionizing radiation.
A less invasive test being used more frequently is the cardiac CT, or EBCT. This involves detection of calcium present in the atherosclerotic plaque or wall of the coronary artery. X-Rays then quantitate the amount and site of calcium. It is a fair screening test but the least accurate in terms of diagnosis and the true evaluation of heart muscle function.
Of all the cardiac testing, the resting EKG is the least specific and sensitive, showing a static record of heart function and an evaluation of heart rhythm at rest. The stress EKG is next, as it helps see what the reaction of the heart is to stress, exercise or oxygen compromise. The CT scan is not specific for, but has high sensitivity for the presence of disease. The Stress echo, and stress MPI and SPECT are the more specific of the non-invasive tests, but are expensive and not done routinely unless there is a medical indication for them. A cardiac catheterization still remains the gold standard for information regarding heart function and imaging of the cardiac vessels, but of course is an invasive procedure.
The information contained on this page is not intended to provide medical advice, which should be obtained directly from your physician.