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The purpose of this study is to demonstrate the blood supply to your heart muscle (the myocardium), under stress and resting conditions.
On arrival, we will take a detailed medical history. Please tell us if you are asthmatic. If you are female you will be asked to change into a gown. We will place electrodes on your chest to monitor and record your E.C.G. Your blood pressure will be taken. A venflon (small needle) will be placed into a vein in your arm. Through the venflon you will be given a pharmaceutical (either adenosine or dobutamine, depending on your medical history). If we give you adenosine the infusion will last 6 minutes and the radioactive tracer will be injected at 3 minutes. If we give you dobutamine, the infusion may last 10 minutes or longer and the doctor will decide when to inject the radioactive tracer. This tracer travels in the blood vessels into the heart muscle. Your pulse, E.C.G, and blood pressure will be monitored during this period. You may then be asked to drink some water or milk or to eat a biscuit.
The scan is carried out 30-45 minutes later. For this, you will lie down on a couch with your arms above your head. A picture of your heart will be taken by a gamma camera, which moves in a semicircle around your chest. In order to get good pictures, the gamma camera will be close, and you will be asked to remain still. The picture will take 20 minutes. Removal of jewellery and metal objects around the chest region is required.
You will be asked to return in the afternoon for a re-injection (resting) scan. For this you will be given another injection of the radioactive tracer without the adenosine or dobutamine infusion, using the same venflon. If your condition is appropriate we will give you 2 sprays of nitrate before the injection. The picture will be repeated 45-60 minutes later and additionally for this your E.C.G will be monitored.
If you are pregnant, or you think you might be pregnant, you need to inform your doctor or the Nuclear Medicine staff before attending your appointment. In general, exposure to radiation during pregnancy should be kept to a minimum and it may be necessary to postpone your scan. If you are breast-feeding it is advisable to feed the baby before the injection and to substitute breast-feeding by formula feeding for the first 12 hours following the injection and to express and discard any milk secreted during this period.
We would prefer that you do not bring more than one person with you. However it is advisable not to have a pregnant woman or a small child with you. This is to avoid exposing them to unnecessary radiation. It is also preferable to avoid prolonged close contact (hugging a child / sitting a child on your knee for more than half an hour) for the rest of the day.
Do not eat breakfast on the morning of the test. Do not have tea, coffee, cola drinks, chocolate, and any medication containing caffeine for 18 hours before the injection. If you are diabetic, eat as usual (but no tea or coffee) and take your usual medication for diabetes. After the first part of the study you may eat normally and have one cup of tea, coffee, chocolate or cola drinks. All your usual tablets should be taken with these three exceptions:
1. The following drugs should not be taken on the day of the appointment until the test is completed: Theophyllinine , Aminophylline, Adenosine, Assasantine, Dipriclypidamole, (Persantin), This last drug (Persantin) should be stopped 24 hours before the test.
2. The following drugs should not be taken on the day of the test until after the stress study: Isosorbide dinitrate, GTN Patches, GTN tablets, GTN spray (emergency use allowed).
3. Beta blocker should not be taken before the study if you are an asthmatic, or if you are known to have severe heart disease. Otherwise take these tablets normally.
PLEASE BRING ALL YOUR MEDICATION WITH YOU.
The needle prick from the injection may hurt a little. The pharmaceuticals we infuse may give you a headache, you may feel breathless and your heart may beat faster. Do not worry, the doctor or the nurse will monitor you throughout the infusion and ensure your safety at all times.
The amount of radioactivity you receive in this study is strictly within the recommended national level. At this level, the benefit to you from a diagnosis of your condition far outweighs the risk (negligible) of any harm associated with the radiation you will receive.
You may eat as normal. The more fluid you drink the better, as the radioactivity is passed out in the urine. No extra precautions need to be when passing urine.
The Nuclear Medicine doctor will report on the study; the result will be sent to the doctor who requested the study.