Over the last decade, transoesophageal echocardiography (TOE) has evolved as an essential ultrasonographic technique for rapid bedside tomographic evaluation of the cardiovascular system. Imaging from the confines of the gastro-oesophageal track reduces signal attenuation and permits the use of higher ultrasound frequencies, thereby providing an enhanced spatial resolution. Although interpretation of the structural and haemodynamic information from TOE needs training, the technique can be readily integrated in day to day clinical algorithms, particularly those that demand quick medical decision making. TOE has a wide applicability and its role currently expands beyond the realm of clinical cardiology. An increasing number of anaesthetists, surgeons, and intensivists now use it routinely for monitoring and guiding operative procedures, interventions, and managing critically ill patients. This article provides a brief overview of the indications, imaging techniques, pitfalls, and the emerging trends in the application of TOE.

HISTORY

TOE for recording continuous wave Doppler velocities of cardiac flow was first described by Side and Gosling in 1971.¹ Subsequently, the first transoesophageal M mode echocardiogram was reported by Frazin and colleagues in 1976,² while Hisanaga and colleagues in 1977 illustrated the use of cross sectional real time imaging using a scanning device that consisted of a rotating single element in an oil filled balloon mounted at the tip of the gastroscope.³ The initial acceptance of TOE was offset by the logistic difficulties of introducing rigid endoscopes. The ensuing technological developments that facilitated the transition of TOE to its present clinical status included the introduction of the flexible endoscope, miniaturisation, and improvements in transducer designs, serial improvement in scanning capabilities from monoplane, biplane to multiplane views, and the addition of spectral and colour Doppler imaging. TOE is currently used in approximately 5–10% of patients being evaluated in the cardiovascular ultrasound imaging and haemodynamic laboratory.

INSTRUMENTATION

TOE can …