Coronary artery disease, or CAD, is one of the leading causes of death in the R.S.A. Each year, hundreds of people die from CAD and hundreds of people suffer myocardial infarction, which is a heart attack. Most CAD is caused by atherosclerosis, which is commonly referred to as "hardening of the arteries." This occurs when fatty deposits, scar tissue, calcium and other materials, build up inside the walls of the coronary arteries, the arteries that supply blood to your heart, causing them to become thick and narrow.

Blood transports oxygen; when the heart’s supply of oxygen-rich blood is cut off, due to a blockage or spasm in the coronary artery, angina, or chest pain, results; the heart cannot function properly and, in some cases, stops beating.

A heart attack occurs when the blood supply to part of a heart muscle is severely reduced or stopped. Symptoms of a heart attack include uncomfortable pressure, fullness, squeezing or crushing pain in the centre of the chest that continues and is not eased with rest; pain that spreads from your chest to your shoulders, neck or left arm; chest discomfort accompanied by lightheadedness, fainting, sweating, nausea or shortness of breath; and a feeling of doom or danger.

All chest pain should be taken seriously. Seek immediate care if you have chest pain.

Fortunately, CAD can be detected. First, your doctor will gather information about your medical and social histories. Your family medical history is a review of your health throughout your life and helps determine possible hereditary aspects of disease and identify risk factors. Your social history reveals information about your lifestyle and living habits that may impact a disease, such as smoking and alcohol use, recreational activities that may influence general fitness, or job-related factors such as exposure to toxic substances.

Secondly, your doctor will conduct a cardiovascular physical examination. This includes measuring your pulse, respiration and blood pressure; examining the size of your heart by tapping lightly on your chest; listening to your heart’s rhythm and the opening and closing of the heart valves with a stethoscope; checking your pulse in various areas; inspecting the veins of the neck; and determining whether there is oedema, or swelling, in the ankles and legs. Routine laboratory blood tests may also be done.

Many tests are available to diagnose CAD and to monitor its progression. Initial diagnostic tests are simple and noninvasive, that is, they do not require use of catheters or injection of medication, dyes or other substances. Most are done in your doctor's office. Following are examples of these tests:

• An Electrocardiogram, known as an ECG is a test that may be part of a routine examination if you are over the age of 40 or have CAD risk factors. Electrodes attached to your limbs and chest measure the heart's electrical impulses and a machine prints them out in a graph. This test is not a very sensitive test for CAD, but it can detect irregular heart rhythms, some cardiac damage and other problems

• An Exercise stress test is an ECG taken while you walk or run on a treadmill, or ride a stationary bicycle for 10 to 15 minutes at increasing intensity. It shows how your heart responds to the extra demands of physical activity. This test must be carefully monitored by a physician or cardiologist

• A Holter monitor, or ambulatory ECG monitoring, is done if your exercise stress test indicates a problem. When a problem is indicated, the next step is to continually monitor your heart activity for a longer period. This is done with a small cassette recorder and electrodes worn under your clothing as you perform regular activities. The cassette records a 24- to 48-hour ECG. During this period, you will be asked to keep an accurate diary of your activity and any symptoms to compare to the recording obtained at the time they occur

• A Chest x-ray produces an image on film that outlines your heart, lungs and other structures in your chest. It can detect enlargement of the heart or arteries, the presence of abnormal calcium deposits which may be a sign of blocked arteries, and the condition of the lungs

• An Echocardiograph is a diagnostic test that beams ultrasound waves at the heart and uses the returning echoes to create a picture of the heart. It accurately measures your heart's dimensions, sees its overall shape and pumping action, determines the structure and function of the valves, and assesses blood flow through the heart. If used immediately after an exercise stress test, it can reveal abnormal heart contractions, which are an indicator of CAD

If you have symptoms of heart disease and the tests mentioned have not supplied the necessary information, your doctor may order further testing. The following tests are usually done in a hospital or outpatient clinic:

• Nuclear Imaging is a series of tests that tracks very low doses of a radioactive substance as it travels through the heart. The radioactive substance is injected into a vein in your arm. Computers and cameras capture an image of your heart and coronary arteries, revealing features of your heart's function and blood flow. Nuclear imaging can show the size of your heart chambers, how effectively your heart pumps, how well your coronary arteries supply the heart muscle with blood, whether there is scarring of the heart muscle from a previous heart attack, and the status of lung circulation. Additional information can be obtained by conducting the test in combination with an exercise stress test

• Angiography, or cardiac catheterization, is a test where a thin, hollow, flexible tube called a catheter is threaded through an artery or vein at your groin or elbow, into the heart, and then into a coronary artery. A dye is injected into the catheter to ensure that the arteries and heart can be seen on x-ray. Angiography is painless, but a tranquilizer is usually administered to relieve anxiety. Although this is a safe, low-risk test, angiography is expensive and used only when heart surgery is a strong possibility

• Finally, Magnetic Resonance Angiography, or MRA, is a test that uses radio signals, magnetic fields and computers to show images of the heart and arteries, and to detect disease. The pictures produced with MRA are similar to those taken with x-rays, but they may show slightly different tissues. Unlike angiography, MRA is noninvasive. It is a highly effective procedure with few risks

A final note

Your age, gender, symptoms, and medical and family history of heart disease help your doctor determine which diagnostic tests you need. If you have already been diagnosed with CAD, ongoing symptoms may indicate the need for further testing. Call your doctor if you have questions or for more information on other topics related to CAD, such as lifestyle changes that prevent the progression of the disease, blood cholesterol, medications and treatments.