Echocardiography has become a widely available and frequently used diagnostic technique in cardiovascular medicine. Due to the simplicity of its application and its noninvasive nature, it is often the test of choice when comprehensive information of the structure and the function of the heart is needed. Since it can be readily performed at the bedside and easily repeated at intervals with little discomfort to the patient, echocardiography is well suited for use in emergency situations and intensive care settings. Coupled with the newer ultrasound modalities such as the spectral and color-flow Doppler imaging, echocardiography can provide critical anatomic and hemodynamic information. It is, however, not without shortcomings. A diagnostically adequate examination depends on the availability of an optimal acoustic window-an area on the chest such as the intercostal spaces, cardiac apex, suprasternal. or the subcostal space, over which the transducer can be applied and the ultrasonic beam can be directed at the heart. Narrow intercostal spaces, calcified rib cartilages. obesity, muscular chest wall, emphysema, and abdominal distension are some of the anatomic factors which impede the ultrasound transmission through the chest or render the transducer placement difficult. In the postcardiac-surgical patient, the surgical dressings, drainage tubes, pacing wires, and air in the mediastinum can interfere with echocardiography. In these situations, the images and the data obtained with the conventional echocardiographic examination are often suboptimal. Many of these difficulties can be overcome by transesophageal echocardiography (TEE).’ An ultrasound transducer mounted at the tip of a flexible endoscope is introduced into the esophagus (Figures 1 and 2). Since there are virtually no interposing structures between the esophagus and the heart, the images obtained are exquisite in detail and clarity. In addition, anatomic details that are seldom seen by conventional echocardiography, such as the proximal coronary arteries, atrial appendages. and pulmonary veins and are easily visualized (Figures 3 and 4).