Also known simply as an “echo,” an echocardiogram is a common diagnostic test that uses sound waves to create pictures of the heart and its vessels. It may also be called a transthoracic echocardiogram. The word “transthoracic” means “across the chest.”

The echocardiogram uses high-frequency sound waves (ultrasound) to get a picture of the four heart chambers and the four heart valves. The sound waves bounce back from the heart chambers and valves, producing images and sounds that can be used by the physician to detect damage and disease.

Because an echocardiogram does not involve any radiation, as opposed to an x-ray, it is a very safe test. In fact, it utilizes the same technology used to evaluate a baby’s health before birth.

To perform a transthoracic echocardiogram, a special gel is placed on the chest over the area being examined. A small device (transducer) is then moved over the gelled area, and images can be seen immediately on a video monitor.

There are several types of echocardiograms, including:

An echocardiogram (or “echo”) is a painless test that uses high-frequency sound waves (ultrasound) to get a picture of the heart chambers and valves. The sound waves bounce back from the heart, producing images and sounds that can be used by the physician to detect damage and disease. It is also called a transthoracic echocardiogram. The word “transthoracic” means “across the chest.”

Depending on which type of echocardiogram is used, an echocardiogram is either noninvasive or minimally invasive. It is used to measure the structure and function of the heart, enabling physicians to:

• Measure the heart wall shape and check for abnormalities in heart wall motion
  
  
• Detect disease or accumulation of fluid in the pericardium (a sac around the heart)
  
  
• Identify blood clots
  
  
• Check the condition of certain blood vessels

During an echocardiogram, the physician or technician uses a hand-held device called a transducer to send and receive ultrasound (high-frequency sound waves) signals. A computer then calculates the travel time of these sound waves to and from the heart. An image of the heart is produced on video monitors, paper, videotape and/or digital storage devices.

An echocardiogram does not require the use of radiation and produces a very reliable image, making it an exceptionally safe test. Because this is the same technology used to evaluate the health of a baby in the mother’s womb it is considered a safe method for examining the hearts of children and pregnant women.

An echocardiogram is often given to patients who have experienced signs and symptoms such as:

• An abnormal heart sound (heart murmur)
• Certain types of chest pain (e.g., angina)
• An abnormal electrocardiogram (EKG)
• An abnormal rhythm of the heart (arrhythmia)
• An abnormal chest x-ray
• Shortness of breath
• Symptoms of heart failure (e.g., shortness of breath, fatigue)
• Symptoms of embolism (e.g., stroke, arterial occlusion)

There are many types of echocardiograms, which include:

• Stress echocardiogram. An echocardiogram performed while the patient exercises in a controlled manner on a treadmill or stationary bicycle at varied speeds and elevations. The wall motion of the heart’s pumping chamber before and immediately after exercise may reveal evidence of a lack of blood supply to selected areas of the heart muscle. This can help detect blockages in the heart arteries.
  
  
• Chemical stress echocardiogram. A type of stress test that is used with patients who are unable to perform physical activity. A chemical stress echocardiogram measures the reaction of the heart under chemically induced stress in order to assess the wall motion of the heart muscle. A drug (e.g., dobutamine, adenosine) causes the heart to react as if the person were exercising, though the patient is actually at rest. This can help detect blockages in the heart arteries. 
  
  
• Transesophageal echocardiogram (TEE). A minimally invasive echocardiogram that requires a transducer to be inserted down the patient’s throat into the esophagus (the long tube that connects the throat with the stomach). Because the esophagus is located so close to the heart, very clear images of the heart structures and valves can be obtained this position.
  
  
• Intravascular echocardiogram. An echocardiogram performed as part of a cardiac catheterization in which a transducer is threaded into a blood vessel via a catheter. It provides information about plaque and calcium deposits on the inside of the blood vessel. This type of echocardiogram is minimally invasive and, therefore, has a different set of preparations and other considerations.
  
  
• Contrast echocardiogram. An echocardiogram that is performed after a contrast medium is injected that causes blood vessels or other body structures to stand out more clearly.
  
  
• Fetal echocardiogram. An echocardiogram that allows for the physician to view the heart of a baby while still in the mother’s womb. It may be used in the diagnosis of certain congenital heart diseases.

Each type of echocardiogram provides unique information to the physician regarding the heart structures and function. For example, a one-dimensional echocardiogram is very helpful in determining the size of one of the heart’s chambers (atria and ventricles), thickness of the chamber walls, function of the mitral valve and weight of the left ventricle.

The two-dimensional echocardiogram is particularly helpful in seeing the relation of the heart’s chambers to each other, the ejection fraction (a measurement of the strength of the left ventricle), and problems with the heart’s valves.

Doppler ultrasound and its colorized version (the color Doppler) are helpful in detecting a variety of problems, including those of the valves or functional structure below the valves. Doppler can also be an effective tool in screening for pulmonary hypertension in people at risk for developing the condition (e.g., patients with sickle cell anemia).

The three most common types of echocardiograms (one-dimensional, two-dimensional and Doppler) are noninvasive and are particularly useful for diagnosing the following conditions:

The physician may also do a stress echocardiogram or “stress echo” to see how the heart functions during physical activity. Usually, a stress echocardiogram involves conducting the echocardiogram while the patient is exercising on a treadmill or a stationary bicycle, at varying speeds and elevations.

However, if the patient is unable to perform this physical activity, the physician may choose instead to do a chemical (e.g., dobutamine) stress echocardiogram. This is a test in which the patient is given a medication that causes the heart to beat more strongly, showing the physician how the heart would react to the stress of exercise.

In some cases, none of the types of noninvasive echocardiograms can provide the physician with enough information to make a firm diagnosis. For example, the tests may not give accurate information if the patient is obese (having a body mass index of 30 or greater) or has been diagnosed with chronic obstructive pulmonary disease (includes emphysema and chronic bronchitis).

Alternatively, the physician may be concerned that a blood clot is present in one of the heart’s upper chambers (atria), or that fatty plaque is present in the aorta. These areas are located deep in the chest and therefore may not be as visible with a traditional echocardiogram. In these situations, the physician may choose to do a minimally invasive form of the test called transesophageal echocardiogram (TEE). The TEE provides a clear view of the heart and/or blood vessels from the inside of the body instead of the outside.

In addition to diagnosing cardiovascular conditions, there is growing evidence of the usefulness of echocardiograms in assessing the future risk of a coronary event (e.g., heart attack). Researchers have found that in combination with established risk factors, certain echocardiogram findings indicate increased risk. This combined approach may be more effective in identifying people at high risk. Such use of echocardiograms is not yet common, but is likely to gain in popularity as more research is conducted.

The information in this section applies to the more common, noninvasive forms of echocardiograms. Transesophageal echocardiograms (TEEs) and intravascular echocardiograms are more invasive and different procedures are used before, during and after these procedures.

Other than wearing loose-fitting clothing, there are no special restrictions or preparation prior to echocardiograms. In general, patients may continue to eat, drink fluids and take prescribed medication as normal. However, people who are scheduled for a chemical stress echocardiogram are usually told to stop eating and drinking for about four to six hours before the test. This helps prevent any nausea or vomiting during the test.

Occasionally a child undergoing a noninvasive echocardiogram will be given a sedative prior to the procedure.

An echocardiogram can be performed in a variety of settings, including hospitals, cardiac labs, testing centers or a physician’s office. Most tests take about 30 minutes. Stress echocardiograms (both exercise and chemical) make take up to 1-1/2 hours. Additional time may be needed for the physician or technician to record information about the patient and answer all of the patient’s questions. People scheduled for any of the noninvasive echocardiograms are free to drive after the test.

Patients are required to remove clothing from the waist up and are given a hospital gown to wear during the test. The physician or technician will prepare the chest area by applying a conductive gel. People scheduled for a chemical stress echocardiogram will receive an intravenous (IV) line via a needle inserted into a vein at the back of the wrist. The IV line allows medications to be given to the patient without sticking the patient with more needles. 

A hand-held device called a transducer is then placed on the chest directly over the gel and pictures of the chest are seen immediately on a video monitor. At that time, the lights in the examination room may be dimmed to allow a better view of the various monitors that are recording the results of the echocardiogram.

An electrocardiogram (EKG) may also be performed during this test. An EKG is a painless test in which about 10 to 12 small metal devices electrodes are taped to the chest and attached by wires to an electrocardiograph machine. The EKG gives information about the electrical activity of the heart and can help detect abnormal heart rhythms (arrhythmias).

Throughout the echocardiogram, the physician or technician may change the position of the transducer, reposition the patient, or ask the patient to take certain actions, such as holding his or her breath. Each of these changes may help create clearer images of the heart.

Following the echocardiogram taken while the person is at rest, people scheduled for a stress echocardiogram (both exercise and chemical) will have another echocardiogram taken under stress. For an exercise stress echocardiogram, the patient may be instructed to walk on a treadmill or pedal a stationary bike at varying levels of intensity while the echocardiogram is performed. For a chemical stress echocardiogram, a medication such as dobutamine will be given through the IV before additional echocardiogram testing.

When the test is complete, the transducer is removed and the gel is cleansed from the chest area.

There should be no side effects or complications from a noninvasive echocardiogram, although people who had a chemical stress echocardiogram may experience some minor side effects from the medication, such as:

The medication may also cause complications due to the stress it places on the heart. Complications may include abnormal heart rhythms (arrhythmias) or low blood pressure (hypotension).

If a child undergoing a pediatric echocardiogram was given a calming medication (sedative) prior to the procedure, the patient’s parent or guardian should discuss potential side effects with the physician.

A transesophageal echocardiogram (TEE) is a minimally invasive procedure, typically performed after a standard echocardiogram has revealed a possible problem with the heart muscle or valve. The TEE has shown benefit in evaluating the function of an artificial heart valve, in discovering blood clots in the heart, and in helping diagnose congenital or other types of heart disease.

A TEE is also used during heart-related surgical procedures, where it provides the surgeon with important data such as whether the heart valve should be repaired or replaced. It can provide immediate assessment of a valve and detect abnormalities that need to be addressed during the surgery.

During a transesophageal echocardiogram (TEE), a small transducer attached to a tube (echoprobe) is inserted into the esophagus via the mouth and throat after the patient has been mildly sedated. This will not affect the patient’s ability to breathe freely but may temporarily interfere with swallowing. Once positioned in the esophagus, the transducer can transmit very clear images of the heart’s size, structures and function.

A TEE can take up to 90 minutes. Additional time may also be needed for the physician or technician to record information about the patient and answer all of the patient’s questions. People who are scheduled for a TEE are encouraged to arrange for transportation home from the test, because they will be given a calming medication (sedative) that often leaves them feeling groggy or light-headed.

Just before the TEE, the patient will be asked to remove dentures and oral prostheses and to lie down on the left side on the examination table. An intravenous (IV) solution is started and a mild sedative can be administered. Heart and blood pressure monitoring will begin and continue throughout the procedure. Finally, an anesthetic spray is sprayed into the throat to reduce the gag reflex and help prevent coughing or gagging.

The physician will insert the echoprobe and feed it to the esophagus, which runs from the throat to just behind the heart. The patient may be asked to swallow in order to help move the echoprobe into location. Some discomfort at this stage is normal. Once in place, imaging begins. The transducer at the tip of the probe may be periodically repositioned or advanced in the esophagus to obtain particular views.

When imaging is completed, the echoprobe is withdrawn. Monitoring of vital signs will continue after the procedure until the sedative wears off. At that time, the patient will be able to leave the hospital or diagnostic center. People cannot eat or drink anything until the anesthetic spray has worn off and the gag reflex is restored to prevent possible choking.

Complications are rare, but could include:

People who have additional questions or concerns are encouraged to speak with their physician about the procedure.

An intravascular echocardiogram (also called intravascular ultrasound or IVUS) is a minimally invasive procedure performed as part of a cardiac catheterization. It may be performed if a standard echocardiogram has revealed a possible problem, but the test did not provide enough information to be conclusive. It is one of the most accurate tests in the diagnosis of coronary artery disease.

This test is performed using a thin tube called a catheter, which is fed through a blood vessel to a part of the body that needs to be assessed. The catheter is inserted through a very small incision in the groin, arm or wrist. Through this catheter, a transducer is guided up through the blood vessel to the heart. The echocardiogram is then performed along with a variety of other measurements.

People who are scheduled for a cardiac catheterization are encouraged to arrange for transportation home from the test, because they will be given a sedative that may leave them feeling groggy or light-headed.

Physicians generally advise their patients to reduce or stop taking medications that affect blood clotting (anticoagulants and antiplatelets) prior to this test. On the morning of the test, patients may be told to fast or eat only a light breakfast.

Just before the test, a sedative is given through an intravenous (IV) solution and the area of the incision site where the catheter will enter the blood vessel is numbed with a local anesthetic. The test is then performed, and after some recovery time (about six hours), most patients are free to go home. Instructions regarding exercise and exertion, care of the incision area and the use of medications will vary depending on the patient.

The risk of complications during this procedure is very low.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about echocardiogram:

1. Why do I need an echocardiogram?
   
   
2. What do you hope to learn from the test?
   
   
3. What type of echocardiogram will I receive?
   
   
4. If I am having a stress echocardiogram, will I exercise or receive medication?
   
   
5. Do I need any preparation for the test?
   
   
6. Where can I have the test performed?
   
   
7. How long will it take to complete?
   
   
8. When and from whom will I learn the results?
   
   
9. Am I likely to need any follow-up tests?
   
   
10. How often will I need an echocardiogram?