 The aim of this research is to apply cardiac tissue characterization in order to assess left ventricular function in cardiac surgical patients pre and post cardiopulmonary bypass. The procedures to be used include a retrospective review of transesophageal images obtained during conventional intraoperative transesophageal echocardiography TEE for cardiac surgery, as well as a secondary analysis with Tissue Doppler. The results will be compared with hemodynamic data obtained from a pulmonary artery catheter PAC. 