Diagnosing Heart Disease: Echocardiogram

Echocardiogram Definition

An echocardiogram (often called "echo") is a graphic outline of the heart's movement. During this test, high-frequency sound waves, called ultrasound, provide pictures of the heart's valves and chambers. This allows the technician, called a sonographer, to evaluate the pumping action of the heart. Echo is often combined with Doppler ultrasound and color Doppler to evaluate blood flow across the heart's valves.

Why Do I Need an Echo?

Your doctor may perform an echocardiogram to:

• Assess the overall function of your heart.
   
• Determine the presence of many types of heart disease .
   
• Follow the progress of heart valve disease over time.
   
• Evaluate the effectiveness of medical or surgical treatments.

What Are the Types of Echocardiograms?

There are several types of echocardiograms and your doctor will help determine which is best for you.

• Transthoracic echocardiogram: This is the standard echocardiogram. It is a painless test similar to X-ray, but without the radiation. The procedure uses the same technology used to evaluate a baby's health before birth. A hand-held device called a transducer is placed on the chest and transmits high frequency sound waves (ultrasound). These sound waves bounce off the heart structures, producing images and sounds that can be used by the doctor to detect heart damage and disease.
  
  
• Transesophageal echocardiogram (TEE): This test requires that the transducer be inserted down the throat into the esophagus (the swallowing tube that connects the mouth to the stomach). Because the esophagus is located close to the heart, clear images of the heart structures can be obtained without the interference of the lungs and chest.
  
  
• Stress echocardiogram: This is an echocardiogram that is performed while the person exercises on a treadmill or stationary bicycle. This test can be used to visualize the motion of the heart's walls and pumping action when the heart is stressed. It may reveal a lack of blood flow that isn't always apparent on other heart tests. The echocardiogram is performed just prior and just after the exercise.
  
  
• Dobutamine or adenosine/sestamibi stress echocardiogram: This is another form of stress echocardiogram. However, instead of exercising to stress the heart, the stress is obtained by giving a drug that stimulates the heart and makes it "think" it is exercising. The test is used to evaluate your heart and valve function when you are unable to exercise on a treadmill or stationary bike. It is also used to determine how well your heart tolerates activity and your likelihood of having coronary artery disease (blocked arteries), as well as evaluating the effectiveness of your cardiac treatment plan.
  
  
• Intravascular ultrasound: This is a form of echocardiography performed during cardiac catheterization. During this procedure, the transducer is threaded into the heart blood vessels via a catheter in the groin. It is often used to provide detailed information about the atherosclerosis (blockage) inside the blood vessels.

How Should I Prepare for the Echocardiogram?

On the day of the test, eat and drink as you normally would. Take all of your medications at the usual times, as prescribed by your doctor.

What Happens During the Test?

During the test, you will be given a hospital gown to wear. You will be asked to remove your clothing from the waist up. A cardiac sonographer will place three electrodes (small, flat, sticky patches) on your chest. The electrodes are attached to an electrocardiograph monitor (ECG or EKG) that charts your heart's electrical activity.

The sonographer will ask you to lie on your left side on an exam table. He or she will place a wand (called a sound-wave transducer) on several areas of your chest. The wand will have a small amount of gel on the end, which will not harm your skin. The gel is used to help produce clearer pictures.

Sounds are part of the Doppler signal. You may or may not hear the sounds during the test. You may be asked to change positions several times during the exam in order for the sonographer to take pictures of different areas of your heart. You may also be asked to hold your breath at times during the exam.

You should feel no major discomfort during the test, although you may feel coolness from the gel on the transducer and a slight pressure of the transducer on your chest.

The test will take about 40 minutes. After the test, you can get dressed and go about your daily activities. Your doctor will discuss the test results with you.

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Source: MedicineNet.com
http://www.medicinenet.com/echocardiogram/article.htm