Coronary angiography is an X-Ray procedure to show up the arteries that supply blood to the heart muscle (the coronary arteries). If these are narrowed or blocked they can result in angina or heart attack (myocardial infarction), and coronary angiography enables us to better work out how to treat the patient.

The procedure involves putting a tube into the heart via an artery in the arm or leg, and injecting a liquid into the coronary arteries which shows them up when viewed with X-Rays.

Coronary angiography is a procedure carried out by a specialist in the hospital. Your own physician or heart specialist (cardiologist) will organise this in order to find out more about the vessels which supply blood to your heart muscle. It is likely that other tests will be done first, including an electrocardiogram while exercising (Exercise ECG).

You will be admitted to the hospital and checked over prior to the test, and will have some blood tests taken. You will have the test explained to you in detail, and should make sure you are happy that you understand all you want to.

Coronary angiograms are usually undertaken in a hospital which has a cardiac surgery unit, in case any surgery becomes necessary during or shortly after the test. The procedure will vary from place to place, but you will be taken to a room where there are X-Ray machines. After anaesthetising the area in the bend of the arm at the elbow, or in the groin, the specialist will make a small cut in the skin, and insert a long, narrow tube (catheter) into an artery.

He or she will then push the catheter up through the artery into the main artery from the heart (the aorta) and up to the heart, itself. The coronary arteries come out of the aorta just after the last heart valve (the aortic valve). Helped by the X-Ray screen, the specialist will steer the end of the tube into the mouths of the coronary arteries, in turn. While the end of the catheter is in the coronary artery, some special dye which shows up on X-Ray (contrast medium), is squirted through the catheter, and flows into the artery.

This shows up any narrow or blocked segments of the coronary arteries and their branches. The specialist will also look at the main chamber of the heart (the left ventricle) to get an idea of how well the heart is functioning.

During catheterisation of the heart, other aspects of the heart's anatomy and function can be investigated as well, if necessary. If there are short areas of narrowing of the coronary arteries, they are sometimes treated by the same technique but using a special catheter. Here, a balloon is inflated in the narrowed area or a meshwork tube (stent) is left in place which holds the artery open. This procedure is known as percutaneous transluminal angioplasty (PCTA).

The information from coronary angiography will help your specialist advise you on the best treatment for you.

Your doctor will only advise this procedure if there is a strong suspicion that you have significant narrowing of the coronary arteries, as it is not a test completely without risk. Sometimes you will be quite bruised where the artery was punctured.

The contrast medium most commonly used contains iodine, and you will be asked if you are allergic to iodine. Even if you are not, people often get a sensation of flushing when the contrast is injected.

Sometimes people develop some chest pain (angina) or abnormal heart rhythm (palpitation) during angiography. Usually this resolves itself without any treatment. There is a small chance that you could develop a blocked coronary artery as a result of angiography, and thus sustain a heart attack (myocardial infarction), which is, of course exactly what we are trying to avoid.

Overall, coronary angiography is a safe and valuable investigation, which helps to plan effective treatment for people with narrowed coronary arteries (ischaemic heart disease).