Echocardiography has been one of the most significant advances in cardiology in the past two decades. It can provide anatomic, functional hemodynamic, and blood flow information. Conventional transtho­ racic echocardiography has limitations, particularly in certain patients such as those with obesity, chronic lung disease, or chest wall defor­ mity, or in those where a transthoracic approach is difficult for reasons including trauma, life support apparat uses, and surgical dressings. There are also certain disease states or conditions in which transtho­ racic echocardiography expectedly gives incomplete or inadequate in­ formation. Transesophageal echo cardiography has opened a unique "new window to the heart." The immediate proximity of the esophagus and the posterior heart permits exceptionally high resolution images, par­ ticularly of the left atrium, mitral valve, and intraatrial septum. Addi­ tionally, from the stomach (trans gastric views), the ventricles can be dependably imaged. Transesophageal echo cardiography presently is utilized in two environments: intraoperatively and for outpatient examinations. Intraoperatively, TEE is utilized to monitor cardiac function and de­ tect intracardiac air or debris, to diagnose or quantitate cardiac path­ ology, and to access operative results.