Transesophageal echocardiogram (TEE).

What is a Transesophageal Echocardiogram (TEE)?
A transesophageal echocardiogram (often called "TEE") is an imaging test that captures pictures of the heart as it beats. During an echo, a doctor uses a thick wand called a "transducer" to send sound waves to the heart. These sound waves create images that show the size of the heart chambers, how well the heart pumps, and how the heart valves function.
"Transesophageal" means that the doctor places a tube with the transducer down the throat and into the esophagus. The esophagus is the tube that carries food from the mouth to the stomach.
How to Prepare for a TEE Test
Your doctor or nurse will provide instructions on how to prepare.
Before the procedure, your doctor will perform an examination and ask about your medical history. This includes questions about any health problems you have or had in the past, previous surgeries, and any medications you are taking. Inform them about:
Any allergies you have
Any bleeding problems you have – certain medications, herbs, and supplements can increase the risk of bleeding. Some health conditions also increase this risk.
If you have difficulty swallowing food or liquids
If you have trouble moving your neck
If you have dentures, dental devices, or loose teeth
In some cases, your doctor may decide not to perform the TEE based on your medical history or examination. If this is the case, they will discuss your other options with you.
If you are cleared for a TEE, you will also receive information about:

Fasting – This means not eating or drinking anything for a period of time. Ask your doctor or nurse about your fasting schedule. For example, they may ask you to avoid eating or drinking anything (except clear liquids) for at least 6 hours before the procedure and to stop drinking clear liquids at least 3 hours before the procedure.
Taking medications before the test – If you normally take medications, ask your doctor or nurse if you can take them as usual before the test. You should also ask if it's okay to take them with a small sip of water.
What assistance you will need after the TEE if you are going home – For example, you might need someone to drive you home or stay with you for some time as you recover.