Nuclear Cardiology
A nuclear stress test uses radioactive isotopes to assess the blood flow in the heart. Your doctor can assess whether there is an area in your heart that is not getting enough blood perfusion. This could be a sign of coronary artery disease.
The Advanced Diagnostic Center at University Health has a new, top-of-the-line cardiac CT camera that cuts down the amount of time you have to lay down under the camera. Before, it could take up to 20 minutes to capture one set of images. Now, our San Antonio heart specialists can do it in under 10 minutes.
We can also decrease the amount of radiotracer we give you, so you are exposed to a smaller amount of radiation compared to older technology.
Stress Testing
Exercise treadmill testing
You will be attached to an EKG machine while walking on a treadmill. This test will assess your exercise tolerance, symptoms as they pertain to exercise and monitors for EKG changes during exercise. You will be monitored by experienced nurses, technicians and doctors throughout your test.
Stress echocardiograms
Stress echocardiograms can be performed with or without medication.
During an exercise stress echocardiogram, you will walk on a treadmill. Once you achieve your age-predicted heart rate, we will take pictures of your heart using the ultrasound machine. This test looks at how well your heart muscle contracts under stress.
Another type of stress echocardiogram uses a medication called dobutamine. It is designed for patients who cannot exercise. You will be given dobutamine, which will increase your heart rate and blood pressure to mimic the experience you would have if you were walking on the treadmill.
While we are administering this medication, pictures of your heart will be taken by an ultrasound machine. We are looking for the heart muscle contraction and how that changes with different doses of medication.
Nuclear stress testing
The nuclear stress test can be performed with exercise or with medication. The exercise nuclear stress test is performed similarly to the treadmill test, but when you reach your age-predicted heart rate on a treadmill, you will be injected with the radioactive isotope and then taken to a nuclear camera that will obtain images of your heart. This test is designed to look at the blood perfusion of your heart under stress.
For those who are not able to exercise, your doctor will administer one of two medications for the nuclear stress test: regadenoson or dobutamine.
The regadenoson test uses a medication that causes dilation of the coronary arteries and gives you a sensation similar to when you are exercising. After administering this medication, you will be given the radioactive isotope and the nuclear camera will take images of your heart to look for perfusion of the heart muscle.
The dobutamine nuclear stress test is similar to a dobutamine stress echocardiogram. We administer the dobutamine to reach the age-predicted heart rate before administering the radioactive isotope. Then the nuclear camera will take images of your heart.
The dobutamine nuclear stress test is reserved for patients with special conditions. We commonly use this for patients who:
- Are allergic to other medications
- Have pre-existing lung disease
- Are being evaluated for a liver transplant
