A nuclear stress test measures blood flow to the heart while at rest and while active. The test creates images of the heart showing where the passage of blood is lower or slower due to damage to the heart muscle. The test involves a small amount of radioactive dye into the patient’s blood stream which is traced to identify and areas of weakness or blockage. This test is often used if a standard stress test does not show the doctor enough information to pinpoint the cause of cardiac health symptoms like shortness of breath or chest pains.
The nuclear stress test primarily helps doctors to diagnose coronary artery disease. The coronary arteries are the essential passages which supply the heart with blood, oxygen and nutrients. When those arteries become blocked, damaged or diseased, the patient may be diagnosed with coronary artery disease which present symptoms including shortness of breath and chest pains. The test also shows doctors the size and shape of your heart. It is important for the doctor to see if there are any enlargements and to monitor its pumping action. It is also useful for doctors to monitor treatment and track improvements in cardiac health. When a treatment plan is administered for coronary heart disease, arrhythmia or other heart conditions, the nuclear stress test can show the doctor if the treatment is working by determining how much exertion the heart can handle.
Before the test begins, the patient will have an IV inserted and sticky electrode patches placed on the chest, legs and arms. The electrodes feed information to an electrocardiogram machine, which will record the heartbeat signals. The dye is injected through the IV and images will be taken of the heart at rest. Once the patient is prepared, they will begin to exercise, most likely by walking on a treadmill or riding a stationary bike, thus putting stress on the heart. If the patient is unable to exercise, he or she will be given a medication to increase blood flow to the heart, simulating the cardiovascular effect of exercise. Once the patient’s heart rate reaches a set target, more images of the heart will be taken while there is increased blood flow. The doctor compares the images and can see any areas of inadequate blood flow.