Echocardiogram: Sound imaging of the heart

An echocardiogram uses sound waves to produce images of the heart. This common test allows your doctor to see the complicated dance that is your heart in motion — ventricles squeezing and relaxing, and valves opening and closing in rhythm with your heartbeat. Your doctor can use these images to identify various abnormalities in the heart muscle and valves.

Who needs an echocardiogram?

Your doctor may suggest an echocardiogram if he or she suspects problems with the valves or chambers of your heart or your heart's ability to pump. This versatile test can even be used to detect congenital heart defects in unborn babies.

Are there different types of echocardiograms?

Various types of echocardiograms are available, including:

• Transthoracic echocardiogram. This is a standard, noninvasive echocardiogram. A technician (sonographer) spreads gel on your chest and then presses a device known as a transducer firmly against your skin, aiming an ultrasound beam through your chest to your heart. The transducer records the sound wave echoes as they reflect off internal structures. A computer converts the echoes into moving images on a monitor. If your lungs or ribs obscure the view, a small amount of intravenous dye may be used to improve the images.
• Transesophageal echocardiogram. If it's difficult to get a clear picture of your heart with a standard echocardiogram, your doctor may recommend a transesophageal echocardiogram. In this procedure, a flexible tube containing a transducer is guided down your throat and into your esophagus. From this vantage point, the transducer can obtain detailed images of your heart.
• Doppler echocardiogram. When sound waves bounce off blood cells moving through your heart and blood vessels, they change pitch. These characteristic changes (Doppler signals) can help your doctor measure the speed and direction of the blood flow in your heart. Doppler techniques are incorporated into most transthoracic and transesophageal echocardiograms.
• Stress echocardiogram. Some heart problems — particularly those involving the coronary arteries that feed your heart muscle — occur only during exercise. For a stress echocardiogram, ultrasound images of your heart are taken before and immediately after walking on a treadmill or riding a stationary bike. If you're unable to exercise, a chemical can be injected into your bloodstream to make your heart work as hard as if you were exercising.

How do you prepare for an echocardiogram?

No special preparations are necessary for a transthoracic echocardiogram. Your doctor will ask you not to eat for a few hours before a transesophageal or stress echocardiogram. If you'll be walking on a treadmill during a stress echocardiogram, wear comfortable shoes. You won't be able to drive after a transesophageal echocardiogram, so you may need someone to take you home after the procedure.

What happens during an echocardiogram?

An echocardiogram can be done in the doctor's office or hospital. After undressing from the waist up, you'll lie on an examining table or bed. The technician will attach sticky patches (electrodes) to your body to help detect and conduct the electrical currents of your heart. If you'll have a transesophageal echocardiogram, your throat will be numbed. You may be given a sedative to help you relax.

During the echocardiogram, the technician will dim the lights to better view the image on the monitor. You may hear a pulsing "whoosh" sound, which is the machine's approximation of blood flowing past the structures in your heart.

Most echocardiograms take less than an hour, but the timing may vary depending on your condition. During a transthoracic echocardiogram, you may be asked to breathe in a certain way or to roll onto your left side. Sometimes the transducer must be held very firmly against your chest. This can be uncomfortable — but it helps the technician produce the best images of your heart.

What do the results mean?

Your doctor will look for healthy heart valves and chambers, as well as normal movement of the heart wall. Variations provide information about many aspects of your heart health, including:

• Heart size. Weakened or damaged heart valves, high blood pressure or other diseases can cause the chambers of your heart to enlarge. Your doctor can use an echocardiogram to evaluate the need for treatment or monitor treatment effectiveness.
• Pumping strength. An echocardiogram can help your doctor determine your heart's pumping strength. Specific measurements may include the percentage of blood that's pumped out of a filled ventricle with each heartbeat (ejection fraction) or the volume of blood pumped by the heart in one minute (cardiac output). If your heart isn't pumping enough blood to meet your body's needs, heart failure may be a concern.
• Damage to the heart muscle. During an echocardiogram, your doctor can determine whether all parts of the heart wall are contributing equally to your heart's pumping activity. Parts that move weakly may have been damaged during a heart attack or be receiving too little oxygen. This may indicate coronary artery disease or various other conditions.
• Valve problems. An echocardiogram shows how your heart valves move as your heart beats. Your doctor can determine if the valves open wide enough for adequate blood flow or close fully to prevent blood leakage. Abnormal blood flow patterns and conditions such as aortic valve stenosis — when the heart's aortic valve is narrowed — can be evaluated as well.
• Structural abnormalities. Many structural problems can be detected with an echocardiogram, including problems with the heart chambers, abnormal connections between the heart and major blood vessels, and complex heart defects that are present at birth. Echocardiograms can even be used to assess a baby's heart before birth.

What are the risks of an echocardiogram?

If you have a transesophageal procedure, your throat may be sore for a few hours afterward. Rarely, the tube may cause a minor throat injury. Your oxygen level will be monitored during the exam to check for any breathing problems related to the sedation medication.

During a stress echocardiogram, exercise or medication — not the echocardiogram — may trigger heart distress, such as an irregular rhythm. Serious complications, such as a heart attack, are rare.

What happens after the test?

If your echocardiogram is normal, no further testing may be needed. If the results are concerning, you may need a repeat echocardiogram in several months or other diagnostic tests. In some cases, you may be referred to a heart specialist (cardiologist) for further assessment. Treatment depends on what's found during the exam and your specific signs and symptoms.

Related

Last Updated: 07/14/2006