Your doctor has asked you to have a cardiac stress test. This is a test that evaluates the blood flow and function of your heart. This online brochure has been prepared by the staff of the Nuclear Cardiology/Cardiac Stress Laboratory to explain the procedure.
WHY AM I HAVING THIS TEST?
There are many reasons why your doctor may have ordered a cardiac stress test for you. There are many different types of stress test, each tailored to the patients condition.
Some (but not all) reasons your doctor may have wanted you to have a stress test are:
- You are having chest pain or discomfort
- You are getting winded or short of breath
- You have had a heart attack or a heart procedure like a bypass or angioplasty
- You are taking heart medicines and your doctor wants to know how well you are doing
- You are having skipped beats or palpitations
- You are scheduled for surgery
- Your doctor has noted a change in your electrocardiogram (ECG)
- You are about to start an exercise program
WHAT IS A STRESS TEST?
There are many different kinds of stress tests:
This test measures your physical condition and heart function. You will have electrocardiogram (ECG) leads placed on your chest. A physician will ask you some health questions and examine you.
You will be asked to walk on a treadmill. It starts at a slow rate of speed at a slight incline and gets faster and steeper every three minutes. Your ECG will be watched continuously, and your blood pressure will be taken frequently.
You should walk on the treadmill as long as possible. The doctor will ask you frequently how you are doing. The test will be stopped when you feel you can't walk on the treadmill any more. Most people just get tired. Some get short of breath or leg pain. A few get chest pain or discomfort. The doctor will stop the test if he or she feels it is not safe to continue.
Myocardial Perfusion Imaging
For some people, the treadmill test alone doesn't give enough information, and your doctor may want us to look at the blood flow to your heart. Alternatively, you may be unable to walk on the treadmill and another type of stress using medications that increase blood flow to your heart may be necessary. These tests involve an injection of a very small amount of a radioactive substance into the catheter in your vein. This radioactive drug is designed to go to your heart muscle in the distribution of blood flow. The dose of radiation to your body is very small. We continue to develop new approaches to further decrease the doses needed to get diagnostic images. The radioactive drug is injected at peak treadmill exercise or at peak blood level of the medication. After completion of the stress test you will be asked to lie under a special camera that records the radiation that is emitted from your heart. Depending on your clinical history you will receive either one injection and scan after exercise or you will receive two injections of the radioactive drug- one after stress and one at rest. The resting injection and scan usually come before the stress part of the test but with some protocols the resting part of the study comes afterwards. We select the protocol based on your history to maximize the information we can obtain in the shortest time and with the lowest possible radiation dose.
As part of the perfusion imaging, you may undergo a low x-ray dosage CT of your heart to measure the amount and distribution of calcium in the coronary arteries, the blood vessels that supply blood to your heart muscle. The coronary calcium score is another non-invasive way to find out whether or not you have coronary artery disease and the extent of the disease.
WHAT INFORMATION DO THESE TESTS PROVIDE?
The treadmill test allows us to get information about your overall health and ability for someone of your age to exercise. Also, how you feel during the test along with the response of your blood pressure and ECG reading can help us figure out if you have a heart problem.
If you are also having myocardial perfusion imaging, the pictures let us look at the blood flow to your heart and also how well your heart is beating. If the exercise scans are normal then your test is complete. Otherwise we compare the blood flow to your heart during the stress portion of the test to the pictures taken while your heart is at rest. If there is a blood flow problem to your heart, we can tell how big an area is involved and how severe the problem is.
WHAT IF I CAN'T WALK ON THE TREADMILL?
While many people can walk on the treadmill even if they feel they are in poor condition, some people cannot walk on the treadmill for enough time to provide sufficient information, and others cannot walk on the treadmill for physical reasons - such as people who have had a stroke, have severe breathing problems, or have blood flow problems in the legs. The treadmill test also may not be valid in some people with certain heart rhythm problems or pacemakers. For people who cannot walk, we perform a "pharmacologic stress test." We give you medicine through the intravenous (IV) line to increase the blood flow to your heart instead of treadmill exercise. You may receive either adenosine or dobutamine.
HOW SAFE IS THIS TEST?
Our laboratory performs more than 3,500 cardiac stress tests each year and we have an excellent record of performing these tests safely. However, there is some risk involved in having a stress test especially if you have severe heart disease. You will be watched very carefully during your test by physicians or nurses with extensive experience in performing stress tests. The test will be stopped if the doctor or nurse feels it is not safe to continue. We are trained and equipped to handle any emergencies should they occur.
WHAT ABOUT RADIOACTIVITY?
If you are having imaging, you will receive agents called radiotracers that let us view the blood flow to your heart. These radiotracers contain a small amount of radioactivity. They have been given for many years and are considered very safe. You can be assured that we use the smallest possible amount of radioactivity to do the test. We strive to minimize the amount of radioactivity that you receive, and for many patients the dose received is about the same amount as they would receive in 2-3 years just from natural (background) radiation. The only special precautions needed after the test is to avoid close contact with children for at least 24 hours or according to the instructions of the technologi-st performing your scan.
If you are pregnant, may be pregnant, or are nursing, please let us know. You should not receive radioactivity.
WHO WILL DO THIS TEST?
The attending physicians, cardiology fellows, nurses, and technologists performing your test are on the staff of the Division of Cardiology of the College of Physicians & Surgeons of Columbia University or Presbyterian Hospital. There is always an attending cardiologist present to supervise the performance of all the tests. Scan interpretation is performed the same day by a board certified attending Cardiologist who also has certification in Nuclear Cardiology.
HOW DO I PREPARE FOR THIS TEST?
There is nothing special you need to do to prepare for the stress test. We ask you to wear comfortable clothing, and if you are going to have a treadmill test, please bring sneakers or other comfortable walking shoes.
If your test is scheduled before 12 noon, it is important that you do not eat or drink anything past 12 midnight. If your test is scheduled for after 12 noon, you may have an early (before 8 am) light breakfast but do not drink coffee, tea, soda, or eat chocolate. The caffeine in coffee, tea, some sodas, and chocolate can interfere with the medicine we may need to give you. If you smoke, please refrain from smoking for at least 4 hours before your test.
You should discuss with your doctor whether or not to take your medicines on the day of the test (with a small amount of water). If you are diabetic, it is very important to talk with your doctor about taking your diabetes medicines or insulin the day of the test. In most cases, you should not take your diabetes medicines since you will not be eating.
WHY CAN'T I EAT?
There are 2 reasons we ask you not to eat before your test. Eating increases the blood flow to the stomach and interferes with the pictures of the heart. In addition, some people get nauseated during the stress test and food can make this worse.
IF YOU HAVE QUESTIONS...
We have tried to cover many questions but realize you still may have questions about the test. The best person to talk with is the doctor who wanted you to have this test. However, you will have ample opportunity to have all of your questions answered by the staff performing the test before it is started.
Please remember not to eat or drink past 12 midnight if your test is before 12 noon. If your test is scheduled for after 12 noon, you may have an early, light breakfast but do not drink coffee, tea, soda or eat chocolate (or any caffeine products) in the morning. Do not smoke the day of your test.
If your test is scheduled at the New York Presbyterian Medical Center, you should come to the 2nd floor of the Milstein Hospital building Flanzer Cardiac Center located at 177 Fort Washington Ave., in upper Manhattan. If you are taking the subway, we are at the 168th St. station of the A, C, 1, or 9 train. If you are driving, you can park at the Medical Center parking lot located at the southwest corner of 165th St. and Ft. Washington Ave.
If your test is scheduled at Columbia Eastside Cardiology, you should come to Suite 460 on the 4th floor of Columbia Eastside Cardiology located at 16 East 60th Street between Madison & 5th Avenue in Manhattan. By subway, take the 4, 5, 6, N, or R train to the 59th or 57th Street Station. If you are driving, you can park at the parking lot located at 767 Fifth Avenue or at 2 East 60th Street (between Madison & 5th).
If you have any questions or need to cancel or reschedule your test, we can be reached at 212-305-5996.