Perfusion Stress TestingPerfusion stress testing provides information about the flow of blood through the coronary arteries to the heart muscle. Perfusion stress testing uses a short-lived radioactive tracer to evaluate blood flow (perfusion) through the coronary arteries to the heart muscle. The exam—which includes images captured at rest, a stress test performed with medication (not exercise) and images captured under stress—may be suitable for a patient who is unable to walk on a treadmill.
A physician may order perfusion stress testing for a patient who:
- Is experiencing chest pains due to suspected narrowed or blocked arteries (angina)
- Has had a heart attack
- Has undergone a surgical procedure to open up the coronary arteries, such as an angiogram, stent or bypass
Perfusion stress testing begins with the placement of an intravenous (IV) line, which will allow the technician to deliver the radioactive tracer to the patient’s bloodstream. After approximately 45-60 minutes, the patient will be positioned face-up on an examination table underneath a gamma camera, which can detect the tracer in the body and “trace” the flow of blood through the heart. The patient will be asked to lie with his or her arms overhead for 15-20 minutes.
During the “stress” portion of the test, the technician will place electrodes (small adhesive patches) on the patient’s chest, wrists and ankles, then connect lead wires from an electrocardiogram (EKG) machine to the electrodes. EKG and blood pressure measurements will be taken before the stress test.
Next, the technician will deliver a pharmacological agent via the IV line to cause the blood vessels to dilate, then deliver a second dose of the radioactive tracer. The patient will lie on his or her back for 20-45 minutes; no exercise is required during the exam.
If the patient experiences medication side effects, such as headache, dizziness, nausea, chest pain or shortness of breath, the test may be stopped or medication may be given to reverse the symptoms.
During a short recovery period, the patient’s heart rate and blood pressure will be monitored until the measurements return to their initial resting values. A series of images of the patient’s heart will then be captured. Due to the wait time needed between each step of the test to ensure the best possible image quality, the entire process can take up to several hours.
What to Expect
The radioactive tracer used in perfusion stress testing is not a drug or dye, and it contains only a minimal amount of radiation. As mentioned above, some patients experience uncomfortable side effects during the procedure, which usually can be alleviated with medication and resolve after the test is complete.
Perfusion stress testing can help a physician diagnose heart disease or another heart-related cause of symptoms such as chest pain and shortness of breath.
The experienced team at Tampa General Hospital’s Heart & Vascular Institute sees a high volume of heart disease patients each year, and we offer the latest options in diagnostic imaging, including perfusion stress testing.