Using a benign chemical agent to “stress” the heart and nuclear imaging agent to visualize the heart, Dr. Chatham can judge the heart’s status. The fundamental difference between an exercise stress testing and pharmacologic stress testing is how the heart is stressed. During the pharmacologic stress test, the patient is given a chemical to induce the “stress” on the heart. Today, Lexiscan (regadenoson) is the chemical agent. It is injected into the IV. The patient will often feel symptoms of exercise, such as shortness of breath, sweating or mild GI symptoms. The chemical is rapidly degraded such that within a few minutes it is out of the system. Of course your unique reaction to Lexiscan can be variable.
Once the heart is under peak stress, a nuclear agent is injected. This allows visualization of the heart. The heart is imaged twice, once with the stress agent causing the heart to be maximally vasodilated and the once when the heart is at rest or without any stress agent in the body. It is the comparison of the stressed heart image to the rest or non-stressed image which allows Dr. Chatham to determine if there is blockage within the coronary arteries.