Mitral flow velocity curves as a function of different loading conditions: evaluation by intraoperative transesophageal Doppler echocardiography.

Transesophageal pulsed wave Doppler echocardiography was performed intraoperatively on 10 patients undergoing coronary artery bypass operation. Mitral flow velocity curves and hemodynamic values were recorded during control conditions and intravenous infusion of (1) nitroglycerin, (2) phenylephrine, and (3) fluids. During nitroglycerin infusion blood pressure and wedge pressure decreased, peak filling velocity decreased, and deceleration time increased compared with control values. During infusion of phenylephrine blood pressure increased, there was a trend toward a decrease in peak filling velocity, and deceleration time increased. During infusion of fluids wedge pressure increased, deceleration time decreased, and peak filling velocity increased. Mitral flow velocity curves are therefore altered by changes in hemodynamic loading conditions.