Transesophageal Echocardiography (TEE) is a diagnostic method used when the chest structure (due to lung disease, deformation, etc.) does not provide echocardiographic images of sufficient quality, or when a more detailed examination of intracardiac structures is required. Also known as cardiac ultrasound or cardiac endoscopy, TEE is an endoscopic examination. In this method, a thin probe (tube) is gently advanced through the mouth into the esophagus, reaching the posterior vicinity of the heart, thereby obtaining very clear and detailed images.

From the 1980s to the present day, thanks to technological advancements, TEE devices have evolved significantly, becoming sophisticated systems capable of meeting clinical needs at the highest level. Consequently, more excellent images of the heart's internal structures are obtained, and diagnostic and treatment processes are optimized in light of these high-resolution images. Modern TEE technology used today allows for an extremely detailed examination of the heart and adjacent structures within the chest cavity. It is an indispensable tool, especially for the comprehensive assessment of heart conditions in intensive care and critically ill patients, and for guiding treatment with more reliable images.

It is important not to confuse TEE with transthoracic echocardiography (TTE), which is a superficial ultrasonography. TTE does not require a special preparation process like TEE.