DR. MIGUEL CASTELLANOS, M.D, P.A.
SOUTHEAST TEXAS CARDIOLOGY
610 Strickland Dr. Suite #100
Orange, Texas 77630
WHAT IS NUCLEAR CARDIOLOGY TESTING?
A nuclear stress test measures blood flow to your heart at rest and while your heart is working harder as a result of exertion or medication. The test provides images that can show areas of low blood flow through the heart and damaged heart muscle. The test usually involves taking two sets of images of your heart — one while you're at rest and another after you heart is stressed, either by exercise or medication.
You may be given a nuclear stress test, which involves injecting a radioactive dye into your bloodstream, if your doctor suspects you have coronary artery disease or if a routine stress test didn't pinpoint the cause of symptoms such as chest pain or shortness of breath. A nuclear stress test may also be used to guide your treatment if you've been diagnosed with a heart condition.
Please check with Dr. Castellanos about the medications you are taking. Bring a list of all of your medications, including over-the-counter (OTC) medications and supplements that you routinely take, to the test appointment. Also bring with you to the test any pills you do not take the day of your test.
If you have asthma: Dr. Castellanos may tell you not to take theophylline (Theodur) for 24 - 48 hours before the test. Please bring your inhaler medication with you to the test.
If you have diabetes: If you take insulin to control your blood sugar, Dr. Castellanos may tell you to take only half of your usual morning dose and to eat a light meal 4 hours before the test. If you take pills to control your blood sugar, do not take your medication until after the test is complete. Bring your diabetes medications with you so you can take it when the test is complete. Do not take your diabetes medication and skip a meal before the test.
SHOULD I TAKE MEDICATIONS THE DAY OF THE TEST?
HOW IS THE TEST PERFORMED?
RESTING PICTURES OF THE HEART
Dr. Castellanos will place an IV into a vein in your arm and inject a small amount of radioactive tracer. The tracer is not a dye or contrast and will not affect your kidney function. After the tracer is injected, you will wait about 15-60 minutes for the tracer to be taken up in the heart muscle. Then you will be asked to lie very still under a camera for about 15 minutes. The camera will rotate around your chest and the images will be recorded on the computer. The gamma camera does not produce radiation; it detects and makes pictures of your heart from tiny amounts of radiation in you. Following your rest study, our trained staff will place EKG leads on your chest and the EKG will be used to monitor your heart constantly during your exercise or medication “stress” test. Blood flow in your heart will be increased with either exercise or medication to dilate blood vessels in your heart.
STRESS TEST: EXERCISE/MEDICATION STRESS TEST
Exercise treadmill test is usually preferred if you can exercise adequately without discomfort or difficulty. You will start walking on a treadmill. At regular intervals, the speed and/or angle of the treadmill will increase until you achieve the right heart rate or you develop symptoms like fatigue that limit your exercise. At peak heart rate, a second dose of radioactive tracer will be injected into the IV. Your heart rate, EKG and blood pressure will be monitored throughout the test. If you are unable to achieve an adequate heart rate with exercise, medication to dilate blood vessels in the heart may be given.
Medication Stress Test - If you can not exercise adequately, an infusion of a medication (regadenoson/Lexiscan) over approximately 10 seconds is given to dilate blood vessels in the heart which is followed by injection of a second dose of a radio tracer that allows measurement of blood flow in the heart muscle by the camera. The stress test protocol takes about one minute, and you will be observed for about 5 minutes before you leave the stress testing room. If you have any undesirable side effects (shortness of breath, flushing, abdominal discomfort, headache) of the stress medication, an antidote (cola, caffeinated coffee or theophylline) can be given which usually eliminates side effects in under one minute.
STRESS PICTURES OF THE HEART
After exercising, you will be asked to lie very still for about 15 minutes. The camera will record images that show blood flow into your heart muscle during exercise. The nuclear cardiologist interprets your study and routinely sends a report to your doctors on the same day.
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