This test is performed by a cardiologist in a sterile operating theatre environment.
You are awake throughout but usually you will be given some medication to relax you. Local anaesthetic is put into an area of skin in your groin or arm. A fine tube is fed from the artery in the groin (or arm) and advanced through the blood vessels to the heart. Dye is then injected so that the coronary arteries that run on the surface of the heart can be seen on an X-ray screen. This gives information about narrowings of arteries that might reduce the flow of blood to the heart muscle. Reduced flow may cause angina or even a heart attack.
After the procedure, the groin sheath is removed and you must lie flat for a period of time to prevent bleeding.