The test takes place in a room called a cardiac catheterisation laboratory. It contains special x-ray and recording equipment. There will always be a nurse available to explain what is happening.
While you are having the procedure you will be linked to a heart monitor, which records your heart rate and rhythm. Your blood pressure will also be monitored throughout the procedure.
A catheter is a long flexible hollow plastic tube about the width of the lead in a pencil. It is passed into an artery either in the groin or the wrist. You will have a local anaesthetic to numb the area where the catheter is put in, so it should not be painful. Then a half centimetre cut is made in the skin either in the wrist or groin.
An introducing tube called a sheath is placed into the artery in the groin or wrist. The catheter is then inserted through this sheath into the artery. The doctor uses x-ray screening to help direct the catheter through the blood vessels and into the correct position in the heart. You will not feel the catheter moving around inside your chest. You can watch the procedure on the video screen if you want to.
When the catheter reaches the entrance to the coronary arteries, which lie on the surface of the heart a special fluid (contrast dye), which shows up on xrays is injected into the coronary arteries through the catheter. X-ray films are taken when the contrast dye is in the arteries and any narrowing and blockages within the coronary arteries are recorded. Contrast dye can also be injected into the left side of the heart to assess the pumping action of the heart. The contrast dye can sometimes cause a hot flushing sensation, which lasts a few seconds. You will be warned to expect this.
You may notice a warm feeling in your groin and may think you have wet yourself, even though you have not. People occasionally feel their angina pain during the procedure. This does not mean anything is going wrong but you should tell the doctor about the pain.
While the x-rays are being taken the x-ray machine will move around and will come close to your head and chest but it won’t touch you. This allows different views of the heart to be seen. You must lie flat with one pillow and you must try and keep still during the procedure.