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About Echocardiography |
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Echocardiograms are performed with ultrasound machines. In children, most echocardiograms are done by a transthoracic technique, meaning that a transducer is placed on the chest.
The exam is done non-invasively (without any incisions being made) and without the patient experiencing any pain. It is also done without X-Rays so it carries none of the risks associated with radiation exposure. Instead, ultrasonic sound waves move through the skin and other body tissues to the heart tissues, where the waves bounce off the heart structures, creating a computer-generated image of the heart walls and valves.
In Children's Hospital Boston's non-invasive laboratory, where echocardiograms are performed, there are seven fully equipped examination rooms surrounding a central reading room. This allows the cardiologists in the reading room to continuously monitor all echocardiography exams in progress. Each examination room is equipped with a state-of-the-art ultrasound machine capable of performing two-dimensional (2D) and three-dimensional (3D) imaging as well as color, spectral and tissue Doppler imaging. Our staff cardiologists also participate in and monitor echocardiography imaging done in the cardiovascular surgical suites, the Catheterization Lab and the Cardiac Intensive Care Unit.
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Transthoracic technique (TTE):
Most echocardiograms for children are done by a transthoracic technique. This involves placing a transducer (an instrument that looks like a small microphone) on the chest. The transducer emits sound waves that go through the tissues, bounce off the heart structures and return to the transducer. The returned sound waves (echoes) are translated into images of the heart by a computer inside the ultrasound machine. This is a painless procedure that cause no damage to the tissues and gives doctors and medical technicians a tremendous amount of detail about the heart structure and function.
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Transesophageal technique (TEE): In special circumstances, echocardiograms need to be obtained with a transesophageal technique. This involves placement of a transducer through the mouth and into he esophagus. It is the same technology as the transthoracic technique, but the ultrasound comes from a transducer that is sitting behind the heart, instead of in front. When this type of echocardiogram is required, anesthesia is used so the discomfort of the exam is minimized.
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Stress echocardiography: Stress echocardiography is a method of evaluating the response of the heart to increased demands. The two usual ways of doing this are either with an echocardiogram just before and just after exercise (treadmill or bicycle) or during infusion of a drug (similar to adrenaline) that mimics the effects of exercise on the heart. This test is often used to look for the effects of exercise on the function of the heart muscle and the heart valves.
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Fetal echocardiography: Fetal echocardiography is an ultrasound test performed during pregnancy to evaluate the heart of the unborn baby. The technique is the same as that used for transthoracic echocardiography, but the transducer is placed on the mother's abdomen instead of on the chest. Fetal echocardiography has been shown to be a very safe procedure for both mother and fetus, and a tremendous amount of information about the fetal heart can be obtained.
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An echocardiogram may utilize one or more of the four special types of echocardiography:
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- M-Mode echocardiography - This is the simplest type of echocardiography, and produces an image that is similar to a tracing rather than an actual picture of heart structures. M-mode echo is useful for measuring heart structures, such as the heart's pumping chambers, the size of the heart itself, and the thickness of the walls of the heart.
- Doppler echocardiography - This Doppler technique is used to measure and assess the flow of blood through the heart's chambers and valves. The amount of blood pumped out with each beat is an indication of the heart's functioning. Also, Doppler can detect abnormal blood flow within the heart, which can indicate such problems as an opening between chambers of the heart, a problem with one or more of the heart's four valves, or a problem with the heart's walls.
- Color Doppler - Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow. This simplifies the interpretation of the Doppler images.
- Tissue Doppler - This sophisticated technique is used to evaluate the function of the heart muscle by measuring the motion of the heart walls.
- 2-D (2-dimensional) echocardiography - This technique is used to "see" the actual structures and motion of the heart structures. A 2-D echo view appears cone-shaped on the monitor, and the real-time motion of the heart's structures can be observed. This enables the physician to see the various heart structures at work and evaluate them.
- 3-D (3-Dimensional) Echocardiography - This technique enhances 2-dimensional echocardiography by providing a depth perception (3rd dimension) and allowing visualization of cardiovascular structures from various angles and view that are not easily achieved by 2-D imaging. Modern equipment allows realtime 3-D echocardiography, which is increasingly been used for enhanced diagnostic imagine before, during, and after cardiac surgery.
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- Congenital defects - abnormalities or deficiencies in one or more heart structures that occur during formation of the fetus.
- Valve disease - one or more of the heart's four valves becomes defective, or may be congenitally (since birth) malformed.
- Cardiomyopathy - an enlargement of the heart due to thickening or weakening of the heart muscle.
- Pericarditis - an inflammation of the membrane (thin covering) that surrounds the heart.
- Aneurysm - a dilation of a part of the coronary arteries or the aorta (the large artery which carries oxygenated blood out of the heart to the rest of the body) which may cause a weakness of the tissue at the site of the aneurysm. In extreme cases, the aneurysm may rupture, which is an emergency situation, causing rapid blood loss out of the blood vessels.
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During an echocardiogram, the technician will need to see your child's chest from the waist up (privacy will be maintained). Your child will lie on a table or bed during the procedure, and the room will be darkened so the images on the echo monitor can be better viewed. EKG electrodes will be attached to your child's chest with adhesive patches. The technician will place gel on your child's chest and then place the transducer probe on the gel. As the technician moves the transducer probe around, he will apply varying amounts of pressure to obtain different images of your child's heart.
Your child will need to stay as still as possible during the echocardiogram, so clear pictures can be obtained. Parents can usually stay in the room to reassure their child during the procedure, but young children may be given a sedative to help them relax and remain still. A nurse will monitor your child during the exam if sedation is administered.
Depending on the results of the echo, additional tests or procedures may be scheduled to gather further diagnostic information.
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More on echocardiography...
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