To assess the potential effects of coronary artery bypass surgery on left ventricular diastolic filling, 12 patients, aged 65 ± 11 years, were studied by serial transesophageal Doppler echocardiograms. Doppler measures of mitral inflow velocity were made before, immediately after, 4 h after, and 20 h after cardiopulmonary bypass (CPB). Left atrial pressure was directly measured and controlled at 10 ± 2 mm Hg for each study period. Mitral maximal early inflow velocity (E)/maximal atrial velocity (A) ratios and atrial filling fractions were calculated as indexes of diastolic function from maximal E and A velocities and their time velocity integrals, respectively. Data sets were available for serial comparison in 11 patients and were also compared with an age-matched control group of normal values. The results of E/A ratios were as follows: control group-1.4±0.2; before CPB-1.7±0.6; immediately after CPB-1.0±0.2 (p <0.05 vs control group, before CPB, and 20 h after CPB values); 4 h after CPB-0.8±0.2 (p <0.05 vs control group, before CPB, and 20 h after CPB values); and 20 h after CPB- 1.3±0.4. Atrial filling fractions were as follows: control group-0.29±0.05; before CPB-0.25±0.06; immediately after CPB-0.43±0.07 (p <0.05 vs control group, before CPB, and 20 h after CPB values); 4 h after CPB, 0.46±0.07 (p <0.05 vs control group, before CPB, and 20 h after CPB values); and 20 h after CPB-0.35±0.06. Alterations in Doppler indexes of left ventricular filling occurred immediately after CPB and persisted 4 h after CPB. These indexes returned to baseline values by 20 h after CPB. This suggests reversible diastolic dysfunction in patients after coronary artery bypass surgery.
- cardiopulmonary bypass
- diastolic function