Evaluation of left ventricular diastolic function during coronary artery bypass grafting by color M-mode Doppler echocardiography

The objective of the present study was to evaluate the effects of the coronary artery bypass graft surgery (CABG) and cardioplegic arrest on left ventricular diastolic function. Ten patients with coronary artery disease were studied by transesophageal Doppier echocardiography. Doppier measurements included peak velocity during early filling (peak E velocity), peak velocity during atrial contraction (peak A velocity), and the ratio of peak E velocity to peak A velocity (E/A). The rate of propagation of peak early filling flow velocity (FPV) was also measured using color M-mode Doppler echocardiography. Hemodynamic and Doppler-derived variables were measured before and after sternotomy, after the end of cardiopulmonary bypass (CPB) and after closure of the sternum. E/A showed a significant decrease after sternotomy and did not return to the pre CPB level. FPV increased after CPB. FPV was correlated with E/A (r=0.54, P=0.013 pre-CPB ; r=0.54, P= 0.014 post-CPB). E/A showed a significant correlation with heart rate. After the influence of heart rate had been eliminated by the analysis of covariance, corrected E/A value showed a significant increase post-CPB compared to that in pre-CPB (0.68±0.29 to 1.10±0.29, P<0.05). In conclusion, FPV and heart-rate-corrected E/A increased after CPB. This suggests improvement of diastolic function during CABG.