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A transthoracic echocardiogram is a test that uses sound waves to evaluate the structure and function of the heart. There are no known risks from exposure to these types of sound waves. Transthoracic echocardiograms are useful in creating images of the heart and its surrounding structures. This type of ultrasound can assess the size of the heart, heart function, valve function, the lining of the heart, and holes in the heart.

A typical echocardiogram will take approximately 30-45 minutes and is performed by a registered Cardiac Sonographer. The study is then reviewed by a Cardiologist who specializes in interpreting echocardiograms.

There are two types of enhancing contrast agents used in echocardiography to help further evaluate the heart. The first type of contrast is called a saline (sterile water) bubble study. The other type of contrast used in our lab is called DEFINITY® .

A bubble study will be performed to exclude the presence of a small hole in the heart. During a bubble study an intravenous (IV) line is placed in the patient’s right or left arm. The doctor or physician assistant will shake the salt water until it forms small bubbles. The bubbles are then injected into the vein through the IV line. In a normal heart the bubbles are only visualized on the ride side of the heart after injection because they are filtered through the lungs. If the bubbles are visualized on the left side of the heart within 8 cardiac cycles, it is suggestive of a small opening in the interatrial septum, which is the wall between the two upper chambers of the heart. This abnormality is usually termed an atrial septal defect or a patent foramen ovale. A bubble study is extremely safe. In the past eleven years of performing bubble studies at Clipper Cardiovascular Associates there have been no serious side effects. The only side effects that can occur, which are minimal, are bruising or infection from the IV line.

DEFINITY® contrast, or OPTISON, is a lipid microsphere – it is not a dye or a radioactive substance. We use DEFINITY® in our lab for transthoracic echocardiograms and exercise echocardiograms. If there is inadequate resolution of 2 or more walls of the heart then DEFINITY® is used to help better visualize the function of these walls for proper interpretation. DEFINITY® is injected through an intravenous (IV) line placed in the patients left or right arm. We have used DEFINITY® for the last five years in our lab, and there have been no documented side effects or adverse reactions.

A Stress Echo, also called exercise echocardiograms, is generally used as a screening tool for coronary artery disease. It combines echocardiogram images with exercise on a treadmill. The patient will be given specific instructions by the exercise technologist who performs the treadmill portion of the test. A 12-lead electrocardiogram is also administered in order to evaluate any changes in the electrical conduction of the heart throughout the entire test. The Cardiac Sonographer will take five specific images of the left ventricle with the ultrasound machine before the patient begins exercising. The same five images will be acquired immediately after peak exercise. Pre and post images are then compared and wall motion of the heart is evaluated by our Cardiologists, who specialize in interpreting these types of images.

A nuclear stress test is a three step process in which 1) images of a patient’s heart are taken at rest, 2) the patient’s heart is stressed to increase the activity level in the heart, and 3) more images of the heart are taken post-stress. In order to achieve the best possible images of the heart, a radiopharmaceutical called Cardiolite is injected into a patient via an IV. Cardiolite is a nuclear radioactive isotope, also called Technetium Sestamibi. The amount of radiation that a patient will be exposed to is comparable to that of a CT scan or X-Ray. The Cardiolite tracer is circulated in the blood through the coronary arteries and into the heart muscle. This tracer allows images of heart activity to be captured using a gamma camera.

At Clipper Cardiovascular Associates, we perform two types of nuclear stress tests:

• Exercise Cardiolite Stress Test® 1 and 2 Day Protocol – An exercise stress test involves the use of a treadmill to stress the heart. A patient will be asked to walk/run on a treadmill during phase 2 of the test and will receive the Cardiolite injection during this process. Exercise stress tests can be administered either in a one day procedure using 1 Day Protocols, or a patient can have the resting phase images taken on one day, and return for the stress and post-stress images on the next day.
• Pharmacologic Cardiolite Stress Test® 1 and 2 Day Protocols – If the patient is unable to stress by walking on the treadmill, a pharmacologic agent called Lexiscan will be used as the stress agent. Lexiscan is a vasodilator which expands blood vessels to increase blood flow to the heart. Lexiscan is injected during phase 2 over a period of 20 seconds. Possible side effects of the Lexiscan include flushing, shortness of breath, chest pain, headache, dizziness, nausea, and stomach discomfort. If the symptoms do not dissipate over time or get worse, the care provider will give the patient a medication called Aminophylline to reverse the effects of Lexiscan. Once the stress test is done, the patient will be brought into the camera room for stress imaging. Just as with the exercise stress test, the pharmacologic stress test can be administered using either a 1 Day or 2 Day Protocol.

A physician will order a nuclear stress test to help diagnose coronary artery disease. The coronary arteries are the major blood vessels that supply the heart muscle with the blood and oxygen it needs to function properly. When the coronary arteries become damaged or diseased due to plaque deposit build up, the heart may develop coronary artery disease. Care providers may also order a nuclear stress test if a patient is experiencing chronic chest pain, angina, or shortness of breath, as these symptoms may be a sign of coronary artery disease. Nuclear images will also show the size and shape of the heart. If a patient has recently had a heart attack, nuclear imaging is used to determine how much damage has been done to the heart muscle by measuring the ejection fraction (the fraction of blood that is pumped out of the right and left ventricles with each heart beat). Patients that are undergoing surgery may have a nuclear stress to see if their heart is strong enough to withstand the stress of a long medical procedure.

When you arrive at Clipper Cardiovascular Associates for a nuclear stress test, a technologist will bring you into the stress lab to go over your medical history, answer questions and ask you to sign a consent form for the test. After this intake process, the technologist will insert an IV. Once the IV has been securely inserted into your vein, the technologist will administer the Cardiolite tracer injection through the IV for the resting images. The tracer takes approximately 45 minutes to circulate through the body to the heart. After the injection the technologist will take you out to the waiting room for the 45 minute wait period. During the 45 minute wait period the technologist will ask you to drink at least one glass of water. The activity from the Cardiolite injection will not only be in your heart, but also in your liver, gallbladder and intestines. Water will move the activity in your gut away from the heart, so clear images can be taken when you are under the gamma camera.

After the 45 minute wait period, the technologist will bring you into the camera room where you will be asked to lie on your back with your arms over your head. The camera will then rotate around your chest and takes images for approximately 15 minutes. After the resting images are complete the technologist will bring you into the stress lab where a technician/technologist will attach electrodes to your chest and wires to those electrodes for the EKG. The EKG is used to record the activity of your heart rhythms during the stress test. A blood pressure cuff will be wrapped around one of your arms so blood pressure can be measured before, during, and after the stress test.

After the securing the EKG leads and wires, as well as the blood pressure cuff, a care provider will come into the stress lab and ask you stand on the treadmill and start to walk. The speed and incline of the treadmill will increase every three minute until the patient reaches 85 to 100% of their maximum heart rate. Once you reach a certain heart rate during your exercise, the Cardiolite tracer will be injected through the IV. You will be asked to walk/run for at least another minute to help circulate the injection. When the treadmill has come to a complete stop the technologist will have you sit or lay down for 5 to 10 minutes to recover before you are brought back into the camera room for stress imaging. Stress imaging is done exactly the same way as the resting images, except that your heart rhythm will be monitored by a three lead EKG machine. This allows an ejection fraction measure to be acquired from the heart while you lie under the camera. After stress imaging is done, the technologist will remove the IV and answer any other questions you may have before you leave. When the IV is removed you are free to leave the facility and results of the test will be discussed during a follow up appointment or over the phone.

• Do not eat or drink any fluids, with the exception of water, two hours prior to exam.
• Do not eat or drink any products that contain caffeine; caffeine can affect your heart rate and rhythm.
• Wear or bring comfortable, loose-fitting clothes and a pair of running, walking, or cross training shoes. Make sure any shirt that you choose to wear does not have metal objects on it, as metal can disrupt the heart imaging.
• Bring a medication list or any medications that your care provider has informed you to take before or after the test.
• If you are a diabetic, please ask the care provider if there are any special instructions for you to follow on the day of the test.
• Please consult with your care provider if you have any questions about medications you should not take on the day of the test.

Nuclear stress testing is a safe procedure, but as with any medical procedure, there are some risks involved:

• Although rare, it is possible to have an allergic reaction to the tracer agent (Cardiolite); patients may develop a rash, swelling, nausea or headache.
• Low blood pressure may result from the exercise portion of the stress test that may lead to dizziness or lightheadedness.
• Although rare, there is a risk of having a heart attack during stress testing.
• Exercise sometimes leads to arrhythmias; these generally stop after exercise.
• Chest pains, shortness of breath and fatigue can all occur during and after stress testing. These symptoms usually subside during recovery.