A Study to Determine the Effect of Bi-Ventricular Pacing on Cardiac Hemodynamics After Coronary Artery Bypass Graft

The purpose of this study is to determine, using echocardiography, whether bi-ventricular pacing improves the contractile force by resynchronizing both ventricles, thereby improving and/or correcting the paradoxical septal movement. Primary Hypothesis: * Bi-ventricular pacing post cardiac surgery will result in at least a 10% increase in cardiac index (CI) as compared with standard atrio-right ventricular pacing. Secondary Hypothesis: * Bi-ventricular pacing post cardiac surgery will result in at least a 10% increase in cardiac index (CI) as compared with atrio-left ventricular pacing and right atrium pacing.