In the afternoon of my second day at UNC’s Heart and Vascular center, I sat in on more stress tests, however this time around, they were nuclear stress tests. Nuclear stress tests have the same general goals and functions as the aforementioned exercise stress test, however are administered in a different way. Nuclear stress tests are geared towards patients who are physically unable to get on the treadmill and complete the exercise portion necessary for the other type of stress test. This could be due to physical limitations such as weak joints, those who are wheelchair bound, or any other limitations that make it impossible to reach their target heart rates by exercising on the treadmill. Instead, two sets of images are taken of the heart, the first of the heart at rest, and the second of the heart under ‘stress’.
First, a radiotracer in injected into the bloodstream through an IV in the wrist. After this is given time to thoroughly circulate through the bloodstream, the first image is taken. The ‘camera’ used collects input from the previously administered radiotracer, these signals creating an image displayed on a computer screen. Once the initial, resting photos have been taken, the patient is given a medication (again, through the radial IV) that essentially tricks the body into believing that it is stressed. This experience can be incredibly uncomfortable for about 3-5 minutes until the effects wear off. The nurse in-house also taught me an additional trick- the medication binds to certain receptors in the body and a diet coke happens to bind to those same receptors. As a result, giving a patient a diet coke will make them feel better, because it will help ease the effects and strength of the medication quicker. Finally, the second set of images are taken once the heart is sufficiently active, or ‘stressed’ by the medication, and the patient is done with their testing. Based on the results and interpretations of the images presented, doctors are able to identify blockages, diagnose coronary artery disease, understand what course of treatment to pursue, and even how treatment may be working. The image below represents what doctors see when they receive results back from nuclear stress testing:
