A stress test assesses how the heart functions under increased demand. It helps healthcare providers understand the heart’s capacity and identify issues not apparent at rest. By monitoring the heart’s response to physical exertion or medication, doctors gain insights into its overall health. These tests are important for evaluating heart-related concerns.
Understanding the Myoview Stress Test
The Myoview stress test is a type of myocardial perfusion imaging (MPI), also known as a nuclear stress test. It evaluates blood flow to the heart muscle (myocardium) at rest and under stress. This imaging helps identify areas not receiving sufficient blood supply.
The term “Myoview” refers to the radioactive tracer used in this procedure, Technetium-99m Sestamibi. This tracer is injected into the bloodstream and is absorbed by heart muscle cells. The amount of tracer taken up by these cells is directly proportional to the blood flow reaching that part of the heart. Specialized cameras then detect the gamma rays emitted by the tracer, creating detailed images of the heart.
Reasons for Undergoing the Test
Doctors often recommend a Myoview stress test for individuals with symptoms of coronary artery disease. These include unexplained chest pain, shortness of breath, or unusual fatigue, especially during physical activity. The test helps determine if these symptoms are due to blockages in the heart’s arteries.
The test also evaluates individuals with known heart conditions. It assesses blood flow in patients who have had a heart attack or bypass surgery. Additionally, a Myoview stress test can help determine cardiac risk before major non-cardiac surgery, especially for those with existing heart disease risk factors.
Preparing for and Undergoing the Test
Preparation for a Myoview stress test involves specific instructions for accurate results. Patients typically fast for several hours before the test, avoiding food, caffeine, and certain medications. Comfortable clothing is also advisable, as the test may involve physical exercise.
Patients should discuss all current medications with their doctor, as some, like certain heart medications or those with caffeine, may need to be temporarily stopped. On the test day, an intravenous (IV) line is inserted, usually in the arm. The procedure consists of two main phases.
The first is the rest phase. A small amount of Myoview tracer is injected through the IV line, and after a short waiting period, images of the heart at rest are captured.
The second is the stress phase, involving either physical exercise on a treadmill or pharmacological stress using medications like adenosine, dobutamine, or regadenoson for those unable to exercise. During this phase, heart rate, blood pressure, and electrocardiogram (ECG) are continuously monitored. At the peak of stress, a second tracer injection is administered, followed by another set of images.
What Your Test Results Reveal
After the Myoview stress test, a cardiologist or radiologist compares images from the rest and stress phases. This comparison identifies how blood flows through the heart under different conditions. The patterns of tracer uptake provide diagnostic information.
Normal results show uniform tracer uptake in both rest and stress images, indicating healthy blood flow to all heart muscle parts. Reduced tracer uptake during stress but normal uptake at rest suggests reversible ischemia, indicating a blockage that restricts blood flow only when the heart works harder. Conversely, reduced tracer uptake in both images indicates a fixed defect, meaning an area of heart muscle has been damaged and no longer receives adequate blood flow. These findings help doctors diagnose coronary artery disease, assess its severity, and guide treatment decisions.