Cardiac Investigation Unit
This busy clinical investigation unit offers inpatient and outpatient tests for heart conditions. Tests can either be requested by a hospital doctor or your GP to be performed on your heart.
The unit is open from Monday to Friday between 9am – 5pm. (GP referrals for electrocardiogram are seen between 10am – 12 and 2pm – 4pm)
The electrocardiogram (ECG): An electrocardiogram, or ECG, records the rhythm and electrical activity of your heart. Several small patches are put on your arms, legs and chest. The patches, called ‘electrodes’, are connected to a recording machine, which picks up the electrical signals produced by each heartbeat. It records a few beats from each set of electrodes onto paper. The test takes about ten minutes and will not be uncomfortable at all.
An ECG can detect problems with your heart rhythm. It can sometimes show if a person has had a heart attack, either recently or some time ago, and sometimes it can show if the heart may be working under strain. The ECG is a simple and useful test.
Exercise Stress Test: An Exercise Stress Test, or exercise ECG, is an electrocardiogram that is recorded while you are exercising on a treadmil. If you get a chest pain or feel uncomfortable when you are being physically active, this test can help to tell if your symptoms are caused by angina, a type of pain that is usually due to coronary heart disease. If you already know you have coronary heart disease, an exercise ECG can give more information about how severe your condition is, as it lets doctors see the changes to your ECG ‘wave form’ while you are doing exercise. (The ECG wave form is the pattern of the rhythm of your heart.) If you have recently had heart surgery, an exercise ECG can also help doctors decide what level of exercise you should do as part of your cardiac rehabilitation programme.
Wear light, comfortable clothes and shoes and do not have a heavy meal before you have your ECG. Exercise raises your pulse rate, however this effect shows up less in people who are taking beta-blockers (a type of medicine for the heart). If you take beta-blockers, the doctor may advise you to stop taking them for one or two days before the test. Several small sticky patches are put on your chest and connected to an ECG recorder to monitor your heartbeat. You will then be asked to exercise, starting off at a very easy rate. Gradually, the exercise made harder either by increasing the speed and/or the slope of the treadmill. A doctor or specially trained technician will carefully check your ECG reading, blood pressure and pulse. The staff will tell you when to stop – usually when they have the measurements they need. They may also tell you to stop if you start getting chest pains, or if you get tired or very short of breath. They will take more ECG readings after you have stopped exercising. The exercise test usually lasts approximately 45 minutes (you will not be on the treadmill for this long).
Echocardiogram: A recorder (probe) is placed on your chest and a pulse of high-frequency sound is passed through the skin of your chest. Lubricating jelly is rubbed on your chest first, to help make a good contact with the probe. The probe then picks up the echoes reflected from various parts of the heart and shows them as an echocardiogram – a picture on a screen. You can see different parts of the heart as the probe is moved around on your chest. The test can take up to 30 minutes.
The echocardiogram can give accurate information about the pumping action of the heart, and about the structure of the heart and its valves. It is a useful test if you have recently had a heart attack or if you have heart failure. It is also used routinely to assess people with valvular heart disease (disease of the heart valves).
24-hour ECG recording: This technique involves continuously recording an electrocardiogram (ECG) over 24 hours. It is usually done as an outpatient and is safe and painless. It can help to diagnose symptoms such as palpitations,which don’t happen very often. You will need to make two visits to the hospital – once to have the recorder fitted and once to return it. Small sticky patches are put on your chest with wires are attached to these and are taped down. The wires lead to a small portable tape recorder which you wear on a belt round your waist. The whole system is very comfortable and quiet so you should hardly be aware of it. You can do everything you normally do, except have a bath or shower, and it is best to wear loose clothing. The doctor will ask you to spend a normal day and do any activity which might bring on your symptoms. You will also need to keep a simple ‘diary’,writing down what activities you do and when, and making a note of any times when you have symptoms such as palpitations or dizzy spells. When the ECG is analysed later, the doctors will pay special attention to the recordings at these times which is why it is important to fill in your diary accurately. Often the doctor will arrange for 24-hour recordings to be made for two or three days in a row (in some cases up to eight days). You will get the results of the monitoring a few days later.
A 24-hour ECG recording may show a fast or slow heart rhythm that may need treatment. It can also reassure you if you think you have palpitations but are in fact just ‘over-aware’ of your normal heartbeat.
Ambulatory Blood Pressure Monitoring: This is a test whereby your your blood pressure is recorded at regular intervals over a 24-hour period.
On a belt around your waist, you wear a portable recorder which is attached, through tubes under your clothes, to a cuff which is wrapped around your arm. You carry on with your normal daily activities and, every hour or so, the cuff automatically inflates and measures your blood pressure. The recorder keeps a record of each blood pressure measurement and the time that it was taken. The next day, when you go back to hospital, the device is taken off. It then prints out a record of all the blood pressure measurements made during the previous 24 hours.
This test gives an overview of all the blood pressure readings throughout the 24 hours. It is particularly useful if your doctor thinks that your blood pressure is unusually high when you have it measured in the surgery or at hospital appointments.