[Transesophageal echocardiography (Part 3): Clinical application Part 1]

Intraoperative transesophageal echocardiography (TEE) has a wide range of applications including monitoring of left ventricular (LV) function, evaluation of natural and prosthetic valves, detection of intracardiac thrombus, mass and vegetation, assessment of surgical repair of cardiac disease, visualization of intracardiac air, positioning of an intraaortic balloon and a coronary sinus catheter, evaluation of thoracic aortic lesions, and so on. Complications are very rare with TEE, but damage of the esophagus or stomach can occur. Gentle manipulation of the TEE probe is always required. Patients should be carefully examined prior to TEE to exclude potential esophageal or gastric lesions. Monitoring of global and regional LV function is the major application of intraoperative TEE. Fractional shortening, fractional area change, and ejection fraction are widely used estimates of global LV systolic function, but these measurements may not accurately estimate overall ventricular performance when regional wall motion abnormalities (RWMAs) exist. Regional wall motion is highly sensitive to myocardial ischemia, and a decrease or cessation of regional contraction is indicative of impaired myocardial perfusion. Assessment of RWMAs is thus very useful for diagnosis of ischemia. Although RWMAs are not always caused by acute ischemia, a new onset of RWMAs, as seen during surgery, almost certainly indicates myocardial ischemia. TEE also allows evaluation of LV diastolic function by analyzing the transmittal flow velocity.