In some people there are disturbances in the electrical system which may cause symptoms such as palpitations, light headedness, fainting, chest pain or shortness of breath. These disturbances may be caused by faults in the normal electrical system (often referred to as 'pathways').
We can test the way that the electricity works in the heart by doing a test known as an Electrophysiology study. This tells us if the electrical pathways in the heart are working normally or if there are extra pathways that are causing problems.
What does an Electrophysiology study involve?
An Electrophysiology study usually requires you to stay in hospital for 2 nights. You may be asked to attend the pre-admission clinic approximately one week prior to your admission to allow us to take some blood samples, a heart, trace (an ECG or electrocardiogram) and a chest X-ray. A doctor will explain the test in detail and will ask you to sign a consent form. We will also check what tablets you take in case you need to stop them for a few days before coming into hospital.
You may be admitted to hospital either on the morning of the study or the evening before. You will not be able to eat or drink for 4 hours prior to the procedure. You may be given a tablet to relax you. A hospital gown will be provided for you to wear. A little plastic tube will be inserted into your arm to enable you to be given any medication you might require during the procedure.
For the study you will be taken in a chair to our operating theatre (the Cardiac Catheter Suite). You should make sure that you go to the toilet before being taken down for your study. On arrival in the Catheter Suite you will be met by a nurse who will stay with you the whole time. You will be asked to lie down on a special table in the room where the study will take place. lf you have any problems with mobility the nurses will help you. You will be awake during the procedure but may be give sedation which will make you drowsy. lf it is uncomfortable at any time during the test or you feel very anxious please let the nurses know.
Before we start, we will place some adhesive recording patches on your chest and back to record the heart beat during the test. You will be asked to lie flat and remain as still as you can. We will put a blood pressure cuff on your right arm and you will feel this tightening up every few minutes. We may also put an oxygen mask over your face. This is routine if you have a sedative.
We will then clean the skin in the right side of the groin and on the right side of the neck with some cold cleaning solution and cover you with clean towels. It is very important that you keep your hands by your side from this point on. The doctor will then freeze the skin with some local anaesthetic in the neck and groin. This may sting. After a few minutes, your neck and groin will be numb and we will be able to start the test. The doctor will place 3 tubes in the main vein in your groin and another in the main vein in your neck. This will not be painful but you may feel some pushing when the tubes are inserted. Through these tubes the doctor will pass long thin electrical wires into your heart to test the electrical system of your heart. The wires are placed in the heart with the help of X-rays which help the doctors to make sure the wires are in the correct position. The X-ray machine will come quite close to you and may move around to allow the doctors to see the wires from different argles. You will not feel the wires when they are inside your heart but you may feel your heart bumping a little. Do not worry as this is quite normal.
Now the wires are in place the doctors can identify any extra pathways within the heart which may be responsible for producing your abnormal heart beat. When such an area is identified a special catheter, known as an ablation catheter, can be inserted and a radiofrequency wave passed through the extra pathway preventing the abnormal beats occurring. It may be necessary to repeat the process a number of times to be sure of success.
Once the procedure is complete the tubes will be removed from your groin and neck and small dressings will be applied to the sites. It will be necessary to press lightly on these areas for a short time to stop any bleeding. The needle will remain in your arm until you return to the ward. You will be taken on a trolley back to your bed.
Once back in bed you will be asked to lie flat for two hours and to remain on bed rest until later in the day. Your blood pressure and pulse will be recorded and your groin and neck observed. You will remain in hospital overnight.
Before you are discharged home a doctor will visit you to explain what has been done and discuss your future management. You will be able to ask any questions that you may have. You will be given an appointment to attend a follow up clinic in 6 weeks.
An Electrophysiology Study with Ventricular Tachycardia [VT] stimulation.
When the abnormal heart beats start in the lower chambers of the heart (the ventricles your doctor may suggest that you have an Electrophysiology study similar to the one described in the previous section but one which concentrates on the lower chambers. For this procedure you will not require a tube in the right side of your neck and only two or three tubes will be inserted into your right groin. Once the wires are in position the doctor will try to identify the area of the chamber which is producing the abnormal beats. It may or may not be possible to reproduce these beats. From the results of the test your doctor will be able to recommend the most appropriate treatment. It is unlikely that any treatment will be given immediately as your doctor will wish to discuss his findings with you before proceeding. When the procedure is complete you will have the tubes removed and return to the ward as described in the last section.
