Echocardiography

Echocardiography 

Definition

Echocardiography is a diagnostic test that uses ultrasound waves to create an image of the heart muscle. Ultrasound waves that rebound or echo off the heart can show the size, shape, and movement of the heart's valves and chambers as well as the flow of blood through the heart. Echocardiography may show such abnormalities as poorly functioning heart valves or damage to the heart tissue from a past heart attack.

Purpose

Echocardiography is used to diagnose certain cardiovascular diseases. In fact, it is one of the most widely used diagnostic tests for heart disease. It can provide a wealth of helpful information, including the size and shape of the heart, its pumping strength, and the location and extent of any damage to its tissues. It is especially useful for assessing diseases of the heart valves. It not only allows doctors to evaluate the heart valves, but it can detect abnormalities in the pattern of blood flow, such as the backward flow of blood through partly closed heart valves, known as regurgitation. By assessing the motion of the heart wall, echocardiography can help detect the presence and assess the severity of coronary artery disease, as well as help determine whether any chest pain is related to heart disease. Echocardiography can also help detect hypertrophic cardiomyopathy, in which the walls of the heart thicken in an attempt to compensate for heart muscle weakness. The biggest advantage to echocardiography is that it is noninvasive (does not involve breaking the skin or entering body cavities) and has no known risks or side effects.

Precautions

Echocardiography is an extremely safe procedure and no special precautions are required.

Description

Echocardiography creates an image of the heart using ultra-high-frequency sound waves-sound waves that are too high in frequency to be heard by the human ear. The technique is very similar to ultrasound scanning commonly used to visualize the fetus during pregnancy.

An echocardiography examination generally lasts between 15-30 minutes. The patient lies bare-chested on an examination table. A special gel is spread over the chest to help the transducer make good contact and slide smoothly over the skin. The transducer, a small hand-held device at the end of a flexible cable, is placed against the chest. Essentially a modified microphone, the transducer directs ultrasound waves into the chest. Some of the waves get echoed (or reflected) back to the transducer. Since different tissues and blood all reflect ultrasound waves differently, these sound waves can be translated into a meaningful image of the heart, which can be displayed on a monitor or recorded on paper or tape. The patient does not feel the sound waves, and the entire procedure is painless. In fact, there are no known side effects.

Occasionally, variations of the echocardiography test are used. For example, Doppler echocardiography employs a special microphone that allows technicians to measure and analyze the direction and speed of blood flow through blood vessels and heart valves. This makes it especially useful for detecting and evaluating regurgitation through the heart valves. By assessing the speed of blood flow at different locations around an obstruction, it can also help to precisely locate the obstruction.

An exercise echocardiogram is an echocardiogram performed during exercise, when the heart muscle must work harder to supply blood to the body. This allows doctors to detect heart problems that might not be evident when the body is at rest and needs less blood. For patients who are unable to exercise, certain drugs can be used to mimic the effects of exercise by dilating the blood vessels and making the heart beat faster.

Preparation

The patient removes any clothing and jewelry above the chest.

Aftercare

No special measures need to be taken following echocardiography.

Risks

There are no known risks associated with the use of echocardiography.

Normal results

A normal echocardiogram shows a normal heart structure and the normal flow of blood through the heart chambers and heart valves. However, a normal echocardiogram does not rule out the possibility of heart disease.

Abnormal results

An echocardiogram may show a number of abnormalities in the structure and function of the heart, such as:

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.

National Heart, Lung and Blood Institute. PO Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.

Key terms

Noninvasive — Pertaining to a diagnostic procedure or treatment that does not require the skin to be broken or a body cavity to be entered.

Regurgitation — Backward flow of blood through a partly closed heart valve.

Transducer — A device that converts electrical signals into ultrasound waves and ultrasound waves back into electrical impulses.

Ultrasound — Sound waves at a frequency of over 20,000 kHz, often used for diagnostic imaging.

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echocardiography /echo·car·di·og·ra·phy/ (-kahr?de-og´rah-fe) recording of the position and motion of the heart walls or internal structures of the heart by the echo obtained from beams of ultrasonic waves directed through the chest wall.

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color Doppler echocardiography  color flow Doppler imaging.

contrast echocardiography  that in which the ultrasonic beam detects tiny bubbles produced by intravascular injection of a liquid or a small amount of carbon dioxide gas.

Doppler echocardiography  a technique for recording the flow of red blood cells through the cardiovascular system by means of Doppler ultrasonography, either continuous wave or pulsed wave.

M-mode echocardiography  that recording the amplitude and rate of motion (M) in real time, yielding a monodimensional (“icepick”) view of the heart.

transesophageal echocardiography  (TEE) the introduction of a transducer attached to a fiberoptic endoscope into the esophagus to provide two-dimensional cardiographic images or Doppler information.

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ech·o·car·di·og·ra·phy (k-kärd-gr-f)

n.

The use of ultrasound in the diagnosis of cardiovascular lesions and in recording the size, motion, and composition of various cardiac structures. Also called ultrasound cardiography.

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echo·cardi·o·graph (--grf) n.

echo·cardi·o·graphic adj.

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echocardiography (ehˈ·kō·karˈ·dē·ˑ·gr·fē),

n diagnostic heart examination that utilizes sound wave technology to noninvasively determine the condition of the organ.

Echocardiography.

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echocardiography

(ek´ōkar´dēog´rfē),
n a diagnostic procedure for studying the structure and motion of the heart using ultrasonic waves that pass through the heart and are reflected backward, or echoed, when they pass from one type of tissue to another.

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echocardiography

recording of the position and motion of the heart walls or internal structures of the heart and neighboring tissue by the echo obtained from beams of ultrasonic waves directed through the chest wall.

Echocardiography is based on the same principle as the oceanographic technique of depth-sounding; that is, it utilizes ultrasound to delineate anatomical structures by recording on a graph the echoes from the heart structures. It is particularly useful in demonstrating, without danger to the patient, valvular and other structural deformities of the heart which formerly required cardiac catheterization or some other elaborate procedure for accurate diagnosis. See also ultrasonography.

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contrast echocardiography

microbubbles in liquid are used as a vascular contrast medium. When injected intravenously in a selected or non-selected location, these can be tracked to demonstrate abnormalities of blood flow.

transesophageal echocardiography

the ultrasound probe is mounted on a flexible endoscope and is positioned in the esophagus over the base of the heart, thus enabling unique viewing projections of structures in this area.