Cardiac Diagnostics (myocardial scintigraphy)
The Myocardial Scintigraphy examines the blood flow to the heart muscle at rest and during exercise. This allows assessing the effects of the narrowing coronary arteries (coronary arteries) on the blood circulation in the heart muscle. Myocardial perfusion scintigraphy is a gentle examination method (cardiac catheterization is not used in this type of examination).
Other names: Cardiac scintigraphy
Used radionuclide: Tc-99m-MIBI (2-Methoxyisobutyl-isonitril)
What is a myocardial scintigraphy?
The myocardial scintigraphy is a nuclear medical examination of the heart muscle. During the examination the blood flow conditions of the heart muscle (particularly of the left ventricle) are examined while the patient is resting and during exercising. This way, the effects of circulatory disorders, which are usually based on narrowing of the coronary arteries, can be evaluated accurately. An insufficient blood supply to the heart muscle can often lead to a fatal heart attack.
The myocardial scintigraphy does not replace an invasive cardiac catheterization; however, in conjunction with the findings, it is a common indication for the performing of constitutes a complementary assessment.
How is this examination performed?
The examination is usually like in a stress echocardiography (ECG) conducted on a bicycle - ergometer. At the highest stress level (i.e., the highest load possible for you as a patient), a small glowing radioactively labeled substance is injected into a vein in the arm, which then accumulates with the blood flow in the heart muscle. After an hour break, special scintigrams are obtained with a gamma camera. These pictures show now how much blood has arrived in the various areas of the heart muscle. The gamma camera with two rotary recording heads requires about 30 minutes for this test. The repeated recordings under resting conditions - are usually performed on the same day - after a further radioactive injection. The camera produces three-dimensional images of the heart muscle, so-called SPECT - technology, that allow for an accurate assessment of the blood flow in the individual heart muscle areas. By connecting with an EKG, the cardiac function and the tolerance level of exertion on the body can be assessed accurately. In exceptional cases, a special drug that has previously been injected into your vein can imitate the stress.
What is important before, during, and after the examination?
You may not eat or drink at least 12 hours before you come to the examination. Please do not drink coffee or cola. Non-carbonated mineral water is allowed. Diabetics should eat a small meal without fat, for example, toast.
Medications for the heart may not be taken 24 hours prior to the exam, beta blockers should be stopped 2-3 days before (if necessary, consult with your family doctor). Please bring your heart medication with you when you come for the examination. You may need to take it before the recordings taken during resting periods. Between the stress and the resting recordings, you may leave the practice, but should not exert yourself and spend the time relaxed.
How long does the examination take?
Both, the rest and stress scintigraphy (scan) are performed in one day; the procedure lasts from morning to afternoon. We can issue a confirmation note to the employer. If necessary, we can perform the two examinations on different days, in which case you will have to reserve approximately four hours for each exam.
What to bring? What to consider?
For the examination, we ask you to bring:
- Your insurance card
- Referral from your physician stating the problem
- Previous findings about already made examinations and treatments and medical reports about already known diseasesn
- the current stress ECG, possibly only the findings
- Medication or medication plan
- Comfortable clothes and shoes (for example sweatpants)
- For the ladies a solid bra
- A towel
- If necessary, bring a change of clothes
- Two calorie-rich meals (such as butter, egg, sausage or cheese sandwich, chocolate, cocoa)
What information is important for us to optimally plan and evaluate the examination?
Before planning or performing the examination, it is important for us to know what specific questions your referring physician would like for us to answer. The more information you can give us about your symptoms and medical history, the more accurate is our assessment.
Please prepare for the following questions:
- Have there been problems with your heart? What? When?
- Have you had a heart attack? When? What treatment? Is a physician’s report available?
- Is a heart valve defect known? (Aortic stenosis)?
- Have specific cardiac examinations previously been performed, such as cardiac catheterization, or invasive treatments (surgery, dilation, STENT)?
- Sind Vorerkrankungen des Herzkreislaufsystems in der Familie bekannt?
- Do you smoke or have you smoked?
- Do you have abnormally elevated lipid levels and / or elevated cholesterol levels (please bring your lab report, if any)?
- What medications do you take regularly (especially heart and blood pressure medications)?
- Are there any previous findings on cardiac examination (e.g. exercise ECG)? If yes, please bring them with you.
What questions can be answered by myocardial scintigraphy?
By using the scintigraphy, we can see how much blood arrives in heart muscle at rest and during exercise. By comparing the rest recordings with the stress recordings, we can determine whether individual regions of the heart are better circulated with blood in comparison with other regions, especially under stress. Decreased blood flow, is an indication that a coronary artery is narrowed (shows decreased blood flow) that there is an increased risk for a heart attack. After a heart attack, you can see how large and extended the scar is that was left by the infarction, and whether a minimal residual blood flow in the infarct area has remained. The answer to this question determines whether surgical treatment is advisable (e.g., a bypass surgery or a STENT).
In addition, statements about the pumping function of the heart muscle can be made and thus also about your physical condition (e.g., after a heart attack, the pumping function is not as good as in healthy and sufficiently perfused tissue).
Risks and side effects and exposure
The radioactive medication only causes a very low radiation exposure, which is of the same magnitude as in normal radiography. Together with us, your treating physicians carefully weighs the risks and what method of examination in that particular case is most beneficial and the least stressful.
In comparison to X-ray contrast agents, side effects such as allergies to the radioactive substance are extremely rare.
The bicycle stress per se rarely causes any complications, even in patients with heart disease. It is important for the accuracy and comprehensiveness of the results that you achieve the highest stress level possible. Only in one of 10.000 to 20.000 examinations, a cardiac arrhythmia problem requiring treatment or a heart attack (1: 40.000) is to be expected.
If a stress test on a bicycle ergometer will not be possible – e.g., in orthopedic diseases - the stress can be artificially achieved by a special drug that is injected into a vein in your arm. These drugs are well controlled in their effect. Side effects such as dizziness, palpitations, chest pain, and breathing problems are rare. Through an antidote (voids the effect of the drug), injected immediately after stress test, these side effects usually disappear immediately.
During the stress test, you are being monitored just like in the exercise ECG. Emergency equipment is, of course, available.
When should the examination not be conducted (contraindications)?
- Pregnancy and lactation (except for rare exceptions))
- Severe organ diseases, which do not permit loading of the cardiovascular systemn
- General infection with fever
- Acute myocardial infarction or severe heart failure (congestive heart failure)
- Uncontrollable high blood pressure
- Severe valvular heart disease (particularly aortic stenosis) and cardiac arrhythmiasn
- Acute inflammation of the heart muscle (myocarditis)
Who pays for the examination?
The cardiac scintigraphy (myocardial scintigraphy) is a standard benefit of all statutory and private health insurances.
Patient information can be downloaded here.