An “echo” is a procedure where sound waves are used to visualize heart structures. It is similiar to an ultrasound used to visualize a baby in the womb. Typically, the probe is placed on the outside of the chest (trans-thoracic echo). In certain situations, however, the images obtained by a trans-thoracic echo are not detailed enough. Since the esophagous runs in close proximity to the heart, an echo probe can be passed into this area and higher resolution images obtained. This is known as a trans-esophageal echo. The procedure is performed under light sedation.