Description of Echocardiography

Echocardiography is a medical examination that uses high frequency sound waves to create detailed images. It is most commonly used to observe images of the heart to enable the overall heart function, heart valves or extent of heart disease to be assessed. Echocardiograms are performed in physicians' offices and cardiology departments in hospitals.

The Science

• Ultrasound waves are what make echocardiography possible. A transducer is used to perform the examination and crystals from within it emit high frequency ultrasound waves. Variations in body tissue density and size cause the ultrasound waves to be reflected back to the transducer at different angles and times. Consequently, an image is produced. Echocardiography may soon replace the x-ray as it produces a more detailed image and there is no exposure to radiation during the exam.

The Examination

• A bare chest is required for the standard echocardiogram to be performed. Three electrodes are then put on the body so a baseline EKG can be obtained. A gel is placed on the transducer and then placed on the body in different positions to get the required images. The standard views for echocardiography are the parasternal long axis view, parasternal short axis view, the apical view, subcostal view and the suprasternal view.

Purpose

• Primarily, echocardiography is used to evaluate the way in which the heart is functioning. The main structures are observed and the condition of each is measured or graded. The size of the chambers and the chamber walls are measured so that any dilation or wall thickening is discovered. The movement of the walls is something that is also looked at. When an echocardiogram is being performed akinesis is something that is looked for. This is a chamber wall that is not moving at all. The final set of things evaluated in echocardiography is valvular function. Problems such as stenosis of the valves can be noticed this way.

Different Types

• The main types of echocardiogram are the transthoracic echocardiogram (TTE), the transesophageal echocardiogram (TEE) and the stress echocardiogram. The standard transthoracic is where the transducer is placed exclusively on the chest area. Transesophageal echo employs the use of a longer transducer that is inserted through the mouth and down the throat. The version of echocardiography that is done by this method is often more effective, as obstruction from the lungs and fat or muscle from the chest is avoided. Stress echocardiography is useful when wishing to see what an individual's heart is doing when it is in a state of exercise. This is provoked by actual physical exercise or a state of exercise mediated by drugs.

Modes

• Other than basic 2-dimensional imaging, other modes of echocardiography are used to obtain more information. The most commonly used is M-mode which is primarily used for fine measurements. These fine measurements include the size of vessels and the size of openings associated with valves as well as the valves themselves. The final mode used is the Doppler imaging mode. This is used to determine the blood flow velocity.