In America, coronary artery disease is the main cause of disease and death. The coronary arteries supply blood and oxygen to the heart. In coronary artery disease, these blood vessels are atherosclerotic, or narrow and stiff. This is because there are areas in the blood vessels that have cholesterol and saturated fat. Since they are narrow, it is hard for blood to flow through them. Thus, the heart does not get the oxygen that it needs.
History and Physical Exam
A medical history and physical exam usually give enough information to determine that someone most likely has coronary artery disease and should be tested, according to David Schwartz, M.D., of the Department of Medicine at the Washington University School of Medicine in "The Washington Manual of Medical Therapeutics." They may have a heaviness or pain in their chest that goes out to their jaw, neck and arm. They may also have difficulty breathing, be dizzy, sweaty and nauseous.
EKG
EKG stands for electrocardiogram. This device gives a record about the electrical activity of the heart, information about the structure of the heart and how it is functioning. The EKG shows the heart rate, the rhythm and any abnormalities in the electrical signals. This diagnostic test also shows whether or not one of the chambers of the heart is too thick, if an area of the heart is without oxygen and if there is an area of dead tissue, as explained by Thomas Bashore, M.D., Professor of Medicine at Duke University Medical Center in "Current Medical Diagnosis & Treatment."
Exercise Stress Test
This diagnostic test is a treadmill. Its use is explained by Dr. Schwartz in "The Washington Manual of Medical Therapeutics." People walk on the treadmill as the speed and incline of the treadmill increases. Their heart rate and blood pressure are checked while they are walking and during their rest period. The EKG is used during the stress test to check on the activity of the heart, while physicians ask whether or not people are experiencing any chest pains.
Pharmacologic Stress Test
The pharmacologic stress test uses medication instead of a treadmill for people who cannot or should not use the treadmill. People who have certain heart conditions, an abnormal EKG result, a muscular or skeletal disease or are obese have this type of diagnostic test. Dobutamine, adenosine and dipyridamole are the medications used, according to Michael Shea, M.D., Professor of Internal Medicine at the University of Michigan Health Systems, in "The Merck Manual for Healthcare Professionals."
Stress Echo
An echocardiogram is an ultrasound of the heart. A stress echocardiogram is a diagnostic test that can be used along with the exercise stress test or the pharmacologic stress test. As explained by Dr. Shea in "The Merck Manual for Healthcare Professionals," this test shows how the wall of the heart moves. It will show abnormal movement if portions of the heart are not getting enough oxygen during a stress test because of coronary artery disease.
Nuclear Stress Test
In this diagnostic test, people have an injection of thallium or technetium when they are taking the exercise or the pharmacologic stress test. These two substances are radioactive materials. In "Current Medical Diagnosis & Treatment," Dr. Bashore writes that these substances can determine if there are areas of the heart without enough oxygen.
References
- "Current Medical Diagnosis & Treatment 2010"; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2010
- The Merck Manual for Healthcare Professionals: Echocardiography
- The Merck Manual for Healthcare Professionals: Stress Testing
- "The Washington Manual of Medical Therapeutics"; Gopa Green, M.D., Ian Harris, M.D., Grace Lin, M.D., Kyle Moylan, M.D.; 2004
