Heart disease is the leading cause of death in the United States. According to the American Heart Association, there were over 445,000 deaths in 2005 attributed to coronary heart disease. The good news is that over 90 percent of people having a heart attack will recover if they seek immediate medical attention.
The best way to avoid having a heart attack is to get screened for heart disease. By identifying your risk for heart disease and taking early, prompt action, you can avoid premature death and unfortunate complications.
Health History and Identification of Risk Factors
The first step in screening someone for heart disease is completing a health history questionnaire. Health history questionnaires inquire about the incidence of heart disease in your family. If anyone had a heart attack or stroke before 65, you may be considered to be at risk for heart disease. Your doctor will also measure your blood pressure and draw a small blood sample to test for total cholesterol, LDL and HDL cholesterol and blood sugar levels. High cholesterol and diabetes are independent risk factors for heart disease. Chances are, your doctor will also conduct a resting electrocardiogram (EKG) to look for arrhythmias or other heart abnormalities at rest. If you're over 40, your doctor may recommend that you take an exercise cardiac stress test.
Basic Exercise Tests
An exercise cardiac stress test is a commonly used diagnostic test designed to diagnose circulation problems in the heart under physical stress. There are a number of test protocols, but all consist of the patient walking on a motorized treadmill with the speed and incline increasing every few minutes. While connected to an electrocardiogram, the physician can monitor the patient's heart and blood pressure responses under increasing demands. The test can be very accurate for diagnosing heart disease, but it is subject to misinterpretation. For a person with multiple risk factors, a positive exercise test is very predictive of heart disease. However, a patient without risk factors may still have an abnormal exercise test and be healthy.
Advanced Testing
If there are doubts about the accuracy of an exercise cardiac stress test, a radionucleide stress test may be ordered. During the procedure, a radioactive isotope like thallium is injected into the patient's vein. Using a special camera, images of the heart are taken at rest and after exercise, and the two images are compared. In a diseased heart, the lack of blood flow will appear as a cold spot, where there is no circulating blood.
Another commonly used test to diagnose heart disease is stress echocardiography. Sound waves are bounced off the heart at rest and during exercise. Hearts with normal blood supplies show complete contractions while being stressed. Hearts with coronary artery disease demonstrate problems with cardiac contractions. Stress echocardiography is often used when a patient has a false positive exercise cardiac stress test.
Coronary Angiography
All of the previously described tests are considered noninvasive tests and are subject to error. The best diagnostic test is the coronary angiography test. During angiography, a small tube is inserted through the groin and guided into the openings of the coronary arteries. A small amount of radiographic solution is injected into the arteries, and images are taken of their circulation. If there is a blockage in the coronary arteries, it will show up in the images.
