Echocardiograms are ultrasound-based procedures that are used to find out if there is an abnormality of the heart that could lead to stroke. There are two main types of echocardiograms:

• Transthoracic echocardiograms (or TTE) examine the heart through the chest. TTEs are the most commonly performed and give information about the size of the heart chamber, the motion of its walls and the movement of its valves.
• Transesophageal echocardiograms (or TEE) examine the heart through the throat. TEEs provide images of the internal structures of the heart and its blood vessels.

Physicians often request a TTE for a patient when they suspect cardiac embolus (blood clot formation in the heart), which is a leading cause of stroke because most blood clots in the heart eventually come loose and travel to the brain. TTE is routinely performed after a heart attack as part of the subsequent stroke evaluation and can be used to prevent a future stroke if an abnormality is detected.

TEEs are usually only prescribed after abnormalities are detected in the results of the TTE, or if the TTE was not able to show enough of the heart structure. A TEE’s images can provide additional information about the heart’s condition.

How echocardiograms work

In TTE, a clear water-based gel is placed on the area of the chest where the heart is located. This lubricating gel allows the transducer (a device that both puts out and detects ultrasound signals) to slide around easily on the skin.

Images of the artery are shown on a video screen when the transducer is placed on the skin. The physician or technologist performing the scan may occasionally reposition the transducer to view these arteries from many different angles. A dye of agitated saline (salt water) may additionally be injected to detect leaking between the heart’s chambers. TTEs are noninvasive and painless, and require about 45 minutes to complete.

A TEE is a little more complicated and requires preparation before it can be done, and may require the presence and care of an anesthesiologist. You may be asked not to eat or drink (except water) for eight hours before the test. (Be sure to speak to your physician about adjusting any medications, such as insulin.)

During the TEE procedure itself, you receive a sedative medicine intravenously to make you more comfortable. You then need to swallow a thin, flexible tube that includes a special probe. You may need to gargle an anesthetic to numb your throat and tongue so that you can swallow the probe more easily. The test takes longer than TTE, usually about 90 minutes, and you may need to stay for a few hours longer for the sedative to wear off.