Nuclear Stress Test is used to examine the images of the heart at rest as well as during exercise. The test visualises the heart chambers, blood pumping capacity and the extent of damaged or dead muscle. This test also gives the information about the blockages in the arteries due to coronary artery disease. Nuclear Stress Test generates the images which can show the areas of low blood flow through the heart and the extent of damaged heart muscle. The test involves taking the images at rest and other in stressful conditions such as exercise or medication. A radioactive dye is used for this test. It is injected in to the blood stream and helps to determine the underlying problem such as coronary artery disease and extent of heart muscle damage after a heart attack when the normal stress test cannot detect the abnormality. This test is also used to guide the treatment with abnormal heart condition.
- To diagnose the coronary artery disease.
- To guide the treatment for heart disorders.
- To check the size and shape of the heart.
The test is generally safe with very rare complications. However the possible risks are:
- Allergic reaction to the radioactive material injected during the stress test.
- Arrhythmias may develop during the procedure and will stop after the exercise.
- In a very rare case it may cause a heart attack.
- Chest pain or dizziness may occur during the test.
- Headache, nausea, shakiness, shortness of breath and anxiety.
- Low blood pressure may develop in some patients which may go away after the exercise.
- Allergic reactions to the contrast dyes or iodine should be informed.
- Ongoing medications should be informed prior to the medical staff.
- Complete blood profile and other blood tests should be ordered before the test.
- Caffeinated beverages, Candies, strawberries should be avoided 24 hrs before test.
- Smoking should be stopped on the day of the test as nicotine will interfere with test results.
- The technician will deliver intravenous line into the arm and inject a radioactive tracer.
- The tracer gives cooling sensation after being injected in to the arm which will take about 20-40 min to absorb the tracer.
- The patient has to lie on the table and the first set of images will be taken at rest and another set of images during exercise.
- The technician will arrange electrodes on the chest, arms and legs.
- The electrode has wires which are connected to an electrocardiogram to record the electrical signals generated by the heart.
- A cuff will be tied to the arms and blood pressure will be monitored during rest and while exercise.
- If the patient is not able to exercise, the doctor will inject a drug which mimics the exercise to increase the blood flow to heart.
- The patient will continue exercising till he develops the symptoms such as chest pain, shortness of breath, palpitations, dizziness and arrhythmia
- At the peak of heart rate another radiotracer will be given and after 20-40 min, the second set of imaging procedure will be initiated. This dye shows the areas of the heart with inadequate blood flow.
- The two sets of images taken at rest and exercise are compared.
- After the test the patient will have to lie down for certain period of time with the monitors attached.
- The doctor will watch for abnormalities as the heart rate and breathing return to normal.
- Normal activities can be resumed within few hours after the test.
- The radioactive tracer will get eliminated from the body through urine or stool. Plenty of water should be taken to flush out the dye from the system.
- Optimal blood flow during rest and exercise indicates the heart is healthy and does not require further tests.
- Optimal blood flow during rest, but not a normal flow during exercise indicates coronary artery disease.
- If the blood flow is low during rest and at the time of exercise, it indicates the heart is not getting enough blood due to coronary artery disease or due to earlier heart attack.
- Area not covered with radioactive material indicates the tissue damage from a heart attack.