Substernal epicardial echocardiography: review of a new technique

Patients after cardiac operation pose a challenge to the treating physician-these patients may become critically ill and are among the most difficult to image using transthoracic echocardiography. Several factors contribute to this, including difficulties in positioning the patient, inability of the patient to cooperate with instructions, surgical dressings, and hyperinflated lungs. Transesophageal echocardiography may be performed when transthoracic echocardiography is not diagnostic; however, transesophageal echocardiography is semi-invasive and does not lend itself to prolonged or repeated monitoring.

Recently, a new approach to echocardiography for use in the patient after operation has been introduced with the modification of the standard mediastinal drainage tube to allow for substernal epicardial echocardiography (SEE). The SEE tube has 2 lumens. The first allows for routine mediastinal drainage and the second has a blind end that permits the insertion of a standard transesophageal echocardiographic probe for high-resolution imaging as often as is desired over the period during which the mediastinal tube is in place.

This article reviews the technique of SEE including a description of the method of performance of SEE (with representative images), a review of the published literature on this new modality, examples of clinical use, and a discussion of the advantages, indications, and limitations of SEE with an eye toward future directions for research.