What is a hemodynamic test?
A hemo (blood)-dynamic (flow) test is a nuclear imaging procedure that evaluates the function of the heart and circulation. The test may also be called a technetium (pronounced tek-nee-see-um) hemodynamic test.
What is syncope?
Syncope (pronounced “sin ko pea”) is the brief loss of consciousness and posture caused by a temporary decrease in blood flow to the brain. Syncope may be associated with a sudden fall in blood pressure, a decrease in heart rate or changes in blood volume or distribution. The person usually regains consciousness and becomes alert right away, but may experience a brief period of confusion.
Syncope is often the result of an underlying medical condition that could be related to your heart, nervous system or blood flow to the brain.
Why is this test recommended?
The hemodynamic test results — along with the results from a blood volume test, heart rate and blood pressure monitoring — help your doctor determine the cause of syncope or certain circulation disorders. The test results also will help your doctor plan a course of treatment.
What are the risks of the test?
As with any procedure, there are risks of the hemodynamic test. Your healthcare provider will discuss the risks and benefits of the procedure with you before the test is ordered.
If necessary, the test will be modified to minimize any potential risks.
The main risk of the procedure is an allergic reaction to the iodine used in the blood volume part of the test, although this is rare. If needed, Benadryl can be given.
One risk of the procedure during IV placement is bruising or swelling at the IV insertion site. These reactions are common. You may also experience pain or discomfort when the IV is inserted. Please talk to the lab staff if you are concerned about the IV insertion.
Scheduling the hemodynamic test
The scheduling secretary will tell you when to report for your hemodynamic test after your tilt test has been completed. If you are scheduling this test by phone, your appointment schedule will be mailed to you.
How long does the test last?
The test takes about two hours to complete. Plan on being at the hospital for two to three hours for your appointment.
Should I take my medications?
Yes. You can take your prescription medications as you normally would, with water. However, do not take diuretics or laxatives before the test.
If you have diabetes, please request a 10:30 a.m. appointment time for your test so you may eat a light breakfast before 7 a.m. and also complete the test in time for lunch.
If you have questions or need help making adjustments to your medications, please call your referring physician. Do not discontinue any medication without first talking to your healthcare provider.
Can I eat before the test?
Eat a normal meal the evening before your procedure. Do not eat or drink anything except water for four hours before the test.
On the day of the procedure, do not eat or drink anything containing caffeine. This includes caffeine-free and decaffeinated products since they may contain small amounts of caffeine. Ask your doctor or pharmacist if any of your medications (prescription or over-the-counter) contain caffeine so that you can make adjustments in your medication schedule the day of the test, if necessary.
What should I wear?
Wear comfortable clothes. You may wear a short-sleeved or sleeveless t-shirt in place of a hospital gown. If you are wearing a long-sleeved or tight-fitting shirt, you may be asked to remove it and change into a hospital gown for the test. You will be given a locker for your clothing.
Please leave all jewelry (including wedding rings), watches and valuables at home.
What should I bring?
Please bring the following to your appointment:
- Recent medical history and physical exam report
- Medical records pertinent to your health condition (if available)
- List of current medications and dosages
- List of allergies (including medication, food and environmental allergies)
- Your insurance card
Where do I go for my appointment?
The appointment secretary will tell you where to check in. Please check in at your scheduled appointment time. Before going to the testing area, your height and weight will be recorded. You will have an opportunity to use the restroom before the test.
Where is the test performed?
The test is performed in a special room called the Hemodynamic Lab.
What happens before the test?
A nurse will explain the procedure in detail and answer any questions you may have.
A pregnancy test may be ordered before the test if necessary, as this test may be unsafe to the baby if you are pregnant. This test is also not performed if you are breastfeeding.
An IV (intravenous) line will be placed in a vein in your arm. The IV is used to take blood samples for blood tests ordered by your doctor, and to inject the radioactive isotope and tagging agent. If necessary, medications are delivered through the IV during the test.
Blood Volume Analysis, Blood Tests:
During the blood volume analysis portion of the test, a small amount of a radioactive isotope, or tracer called iodinated-RISA, is injected. If you are allergic to iodine, IVP dye, shellfish or eggs, the test will be modified to minimize any potential risk of an allergic reaction. Blood samples are then taken and analyzed. The blood volume test is used to evaluate if the amount of blood in your body is appropriate for your gender, height and weight.
A hematocrit measurement is taken. This blood test calculates the percentage of red blood cells in the bloodstream. A low hematocrit reading may indicate the presence of anemia.
Other blood samples may be ordered to determine the level of certain blood pressure regulating hormones produced by your kidneys and adrenal glands or to test for electrolytes in the blood, such as sodium and potassium.
Small, sticky patches called electrodes are placed on your chest. The electrodes are connected to an electro-cardiograph monitor (EKG) that records the electrical activity of your heart as a graph or series of lines on a moving strip of paper. The EKG shows your heart rate and rhythm during the test.
Blood Pressure Monitoring:
A blood pressure cuff will be placed on your arm. This cuff is attached to a monitor so your blood pressure can be measured at specific times and as needed throughout the test.
Imaging During the Test:
During the test, you will lie on your back on an exam table. A special camera called a gamma camera is positioned above your chest and will be used to take a series of images during the test.
A radioactive isotope, or tracer called 99-m-Technetium, is injected into your IV. A computer connected to the gamma camera detects the radiation from this tracer in the body and forms a series of images. These images can be used to measure the function of the heart and specific characteristics of the circulation, such as speed and volume.
The radioactive isotope is not a dye and does not cause any allergic side effects. The amount of radiation a patient receives in a typical nuclear imaging scan is very low, similar to the exposure received in a routine chest x-ray.
The isotope may be injected up to three separate times so that three sets of flow images can be taken throughout a 45- to 60-minute period. Because the pictures are taken at a constant rate, you will need to lie still during the test.
The health care provider may change your position to a sitting position for part of the test (if ordered by the doctor).
Will I be awake during the test?
Yes. You will be awake during the test, but we ask that you try to stay as still and as quiet as possible during the test so the results can be accurately recorded. Please do not move or exercise your legs during the test. We will try to make you as comfortable as possible during the test.
How will I feel during the test?
Throughout the test, the nurse or technician will ask you how you feel. You may not have any symptoms, or you may experience pre-syncope symptoms (called premonitory symptoms), such as light-headedness, nausea and palpitations (fluttering in the chest).
When the radioactive agent is injected into your IV, you may feel a “rush” up your arm and/or pressure in your arm. You may have a metallic taste in your mouth or a strange smell in your nose.
It is important to tell the staff how you are feeling throughout the test. Adjustments can be made between sets of images if necessary to make you more comfortable. Your symptoms, along with the data obtained during the test, will help the doctor diagnose the cause of your condition.
What happens after the test?
The IV will be removed after your last test of the day. Bruising or swelling at the IV site are common reactions, but talk to the lab staff if you are concerned.
You may stay in the lab area an additional 15 to 20 minutes after completing the test, or until all of the symptoms you may have experienced during the test have resolved.
Some of the tracer that was injected is eliminated through urination, and the rest breaks down naturally. You may drink extra fluids to help eliminate the isotope more quickly, although this is not necessary.
You will receive a Homeland Security card that you should carry with you for three months after the test.
Going home after the test
You are usually able to go home after the test. If symptoms are severe, a responsible adult should drive you home after the test.
Your referring doctor will receive a letter that explains the test results. You will also receive a copy of the letter. Your doctor will discuss the test results with you and discuss any necessary changes in your treatment.
Your medications may be changed or you may start to take new medications. You may be referred to other doctors or services to treat your condition.
Other tests may be needed
Depending on the results of the hemodynamic test, other tests may be needed, such as:
- An Isuprel supine test to evaluate your symptoms and how your blood pressure and heart rate respond to adrenaline-like stress. The stress is induced by a medication called Isuprel that is injected into the IV.
- An echocardiogram to further evaluate the heart’s function.
Consultations with other health care professionals may also be needed. If any of these tests or appointments are needed, they will be explained and scheduled.
When will I get the test results?
Usually the hemodynamic test is associated with other tests. A full report with the hemodynamic test results will be sent to your referring or primary care physician in 10 to 14 business days. Your primary care physician will provide recommendations about changing your medications and/or treatment plan, if necessary.