Transesophageal Echocardiography

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US Cardiology 2006;2005:2(1):78-83


Cardiovascular ultrasound is an established imaging modality in the practice of cardiovascular disease (CVD), whether this is provided by a CV specialist or health professionals with training in internal medicine. Transthoracic imaging wherein the transducer is placed on the chest wall has some limitations. These include inadequate quality of images resulting in poor informationÔÇöapproximately 5% of all patients undergoing transthoracic echocardiography may be the subject of poor quality images. Inability to view structures such as the arch of the aorta, descending thoracic aorta, and left atrial image, due to the location of these structures within the thorax, has led to innovations such as transesophageal ecocardiogram (ECG) (TEE) and intracardiac ECG.

Over the last three decades, TEE has evolved as an essential ultrasonographic technique for a rapid tomographic evaluation of the CV system. Imaging from the confines of the gastroesophageal track reduces signal attenuation and permits use of higher ultrasound frequencies, thereby providing superb spatial resolution. Although interpretation of the structural and hemodynamic information from TEE needs additional training, the technique has been integrated in the standard practice of CV ultrasound (CV), particularly those that demand quick medical decision-making. The role of TEE has become established beyond the confines of the CV ultrasound imaging and hemodynamic laboratory, and is being used with increasing frequency in the operating room (OR), with percutaneous procedures such as closure of defects within the heart, percutaneous implantation of valves, and surgical procedures being performed in the catheterization or the electrophysiologic laboratory. An increasing number of anesthetists, surgeons. and intensivists now use it routinely for monitoring and guiding operative procedures, interventions, and managing critically ill patients. This article briefly reviews the indications and emerging trends in the application of TEE.

The initial acceptance of TEE was offset by the logistic difficulties of introducing rigid endoscopes. The ensuing technological developments that facilitated the transition of TEE to its present clinical status included the introduction of flexible endoscope, miniaturization and improvements in transducer designs, serial improvement in scanning capabilities from monoplane, biplane to multiplane views, and the addition of spectral and color Doppler imaging.TEE is currently used either as complementary or stand-alone treatment to a routine transthoracic ECG in approximately 5% to 10% of patients being referred for CV ultrasound imaging test.