Cardiac Echocardiography

Cardiac echocardiography is the practice whereby an echocardiogram is used to produce an image of the heart. Echocardiograms take place in physicians' offices and hospital cardiology departments. A person may be in need of an echocardiogram if their overall heart function, heart valves or heart disease is in need of assessment. There are other uses for cardiac echocardiography and the test centers around the use of ultrasound.

Science

• High-frequency sound waves are used to create an image in echocardiography. A transducer filled with crystals is placed on the patient's chest and emits ultrasound waves that enter the body; these waves are harmless. The different size and density of tissue in the body causes the ultrasound waves to be reflected at varying times and angles. The difference in the time and angle at which the 'echoed' ultrasound waves arrive back at the transducer is what creates the image of the heart.

Examination Layout

• During the standard transthoracic echocardiogram, the patient must remove all their top clothing. Three electrodes are placed on the chest area, usually one on each shoulder and the other on the side of the individual. He or she must then turn on to their left-hand side so the test can be performed. The echocardiographer or sonographer then applies a gel to the transducer and proceeds with the examination. The standard views to be obtained are the parasternal long- and short-axis views, the apical views and the subcostal view. A number of other views may be obtained and the patient may be asked to change positions if the sonographer sees fit.

Purpose

• Echocardiography can be used to evaluate the general functionality of the heart as well as obtaining specific values such as the size of the septum and other heart tissue. The main purposes an echocardiogram would be used for, however, would be to obtain the size of the chambers to ensure there is no dilation of the chambers or thickening of the walls; the efficiency of the pumping action of the heart and the movement of the walls are graded, ranging from normal to dyskinetic (moving in the opposite direction to the desired one) to akinetic (not moving at all). Valve function is also determined with cardiac echocardiography; this is important in identifying problems such as aortic stenosis and other valvular defects.

Different Types

• The main types of echocardiogram are the transthoracic echocardiogram (TTE), which is the standard form, the transesophageal echocardiography (TEE) and the stress echocardiogram. During a TTE, the placement of the transducer is limited to the chest area. During the TEE version, a longer transducer is inserted into the body through the mouth. The esophagus is positioned close to the heart so images are obtainable through this method without obstruction from the lungs and fat or muscle on the chest. The stress echocardiogram is performed when the patient is undergoing stress. This can either be achieved by having the person exercise on a bike or treadmill or undergo a drug-provoked examination where the patient is injected with adenosine or adrenaline, causing the body to go into a condition as if exercising.

Training

• Training to carry out the testing of cardiac echocardiograms involves progressing through a number of levels. This entails taking written exams and performing and interpreting a certain number of examinations on patients. To achieve level one, sonographers must train for a minimum of three months; to proceed to more advanced levels, greater amounts of time must be invested. The National Board of Echocardiography delivers these certifications and monitors the testing.