Substernal epicardial echocardiography: a new ultrasonic window to the postoperative heart

Echocardiographic examination of the postoperative cardiac surgery patient is often problematic because of a poor acoustic window that requires imaging by transesophageal echocardiography. Furthermore, no available echocardiographic methods exist for simple ongoing beat-to-beat assessment of postoperative left ventricular size and function. We designed a modification of a mediastinal drain to allow a transesophageal echocardiography probe to be placed adjacent to the epicardial surface of the heart. After chest closure in a series of 13 patients, we were able to obtain 5- and 7-MHz epicardial images of high quality in both short- and long-axis planes, which also allowed Doppler examination of aortic, mitral, and tricuspid valves in 10 patients. This technique was suitable for prolonged and serial assessment of left ventricular size and function. Though preliminary, these observations suggest that this new substernal epicardial echocardiographic window to the postoperative heart offers a potential for prolonged monitoring of cardiac function as well as rapid and accurate diagnosis in problematic patients.