Treadmill with Radioisotope
(formerly known as Myoview/Cardiolite) Stress Test
A cardiac stress test is one of the basic examinations used to diagnose conditions such as coronary artery disease, arrhythmia or irregular heart beat, or to check on the effectiveness of balloon angioplasty procedures or coronary artery bypass surgery.
Stress tests are non-invasive and relatively low risk procedures whereby the heart muscle is exercised so that the electrical activity of the heart may be monitored under conditions of physical stress. Often, it is possible to discover heart problems while the heart is stressed, whereas those conditions may not be apparent at other times. A cardiac stress test will often be ordered by your physician when you have experienced symptoms such as chest pain and shortness of breath, signs that your heart is not getting enough oxygen, or signs that you may be at risk for a heart attack.
Purpose of the Procedure
A cardiac stress test is used to compare the functioning of the heart before, during, and after exercise and in particular to test how well the heart muscle functions as it is increasingly stressed. The test itself is simply another type of electrocardiogram where the patient exercises to increase their heart rate.
Before the Procedure
Before the cardiac stress test, you should receive an explanation of the procedure and the benefits and risks, and you will be asked to sign medical consent forms to authorize the procedure and acknowledge that you understand the risks. Be sure to ask any questions you may have about the procedure and why it needs to be performed. The more you understand, the better. You will also be asked about your medical history and any symptoms you have been feeling. Please be sure to talk to your doctor about whether or not you should take your medications prior to a cardiac stress test. In particular, blood pressure medications can impact the results of a cardiac stress test, so if you take this type of medication, please ask the doctor if you should stop taking it prior to the procedure.
Because the test involves strenuous exercise, you should avoid eating or drinking 6 hours prior to the test to minimize the possibility that you may feel nausea or cramping during the exercise portion of the procedure
During the Procedure
The equipment used for a stress test includes an electrocardiograph (a machine used to measure the electrical activity of the heart), computer, blood pressure cuff and stethoscope, a treadmill and a special camera.
A specially trained technician or a nurse will usually conduct the test. A nuclear technician will also be present.
You will be asked to remove your shirt and the nurse or technician will clean and shave (if needed) several small areas on your chest. A small electrode will be placed on each area and wires to the electrocardiograph will connect to the electrodes. An IV will be started so we may inject a nuclear isotope (NOT A DYE).
The technician will ask you several questions about your medical history, heart problems and medications.
The technician will measure your resting heart rate and blood pressure, as well as perform the intial electrocardiogram showing the electrical activity of the heart. Once this is complete, you will be asked to step on the treadmill and exercise will begin at a slow pace. Approximately every three minutes, your blood pressure and heart rate will be measured. The treadmill will also speed up and increase in incline so you are walking uphill. Based on your physical condition and how your heart responds to the increased speed and incline, the exercise portion of the procedure may last for a few minutes or perhaps up to eighteen minutes. The technician will ask you throughout the test how you are feeling. If at any time you have any severe fatigue, chest pain or other significant discomfort, you should tell the technician and ask to stop the test. The goal is to exercise enough to get your heart up to a rate that is calculated based on your age. Once we get to that target rate, a small dose of radioactive isotope trace will be injected into the IV. We will have you walk briefly after to help circulate the tracer in the heart.
Immediately after the exercise concludes, you will enter a "cool down" period that will last several minutes. Your blood pressure and electrocardiograms will be monitored. The electrocardiograms during and after your exercise will be compared with the one taken before you exercised. This will provide the physician with information about how your heart reacts under stress.
You will be taken to the Nuclear Medicine Department afterwards where you will lay under a special camera that will detect the isotope tracer in the heart. Special pictures will allow the physician to see how well blood is sent to the heart and will allow us to detect blockages in the arteries of the heart.
After the Procedure
No special requirements or restrictions follow a cardiac nuclear stress test but you may fell fatigued from the exercise. You will also have a follow-up set of pictures in the Nuclear Medicine Department. These will be done without any type of exercise. The information will be similar to the other pictures except these will display your heart muscle at rest. The pictures of the resting heart and the exercised heart will then be compared.