[Validation of the measurement of cardiac output by acoustic quantification in patients with severe congestive heart failure].

The technique of acoustic quantification (AQ), because of its automatic detection of the contours, enables left ventricular volumes to be calculated in real time using the technique of disk summation. The objective of the study was to evaluate the reliability of cardiac output (CO) measurements obtained with AQ based on left ventricle volumes in patients with severe congestive heart failure. Seventeen patients, mean age 68 +/- 11 years, NYHA stage IV, in sinus rhythm and without significant valve regurgitation were enrolled prospectively. CO, measured simultaneously by 2-dimensional echocardiography (2DE), pulsed Doppler echocardiography (DOP) and AQ, was compared to the thermodilution technique (TD) data. CO, measured by AQ, was highly correlated with TD (r = 0.875; p < 0.001) with a small bias (-0.05 l/min). DOP and 2DE were also well correlated with TD (r = 0.835 and r = 0.701, respectively). Concerning ventricular volume measurement, AQ was well correlated with 2DE (for telediastolic, r = 0.892, and telesystolic volumes, r = 0.874). However, telesystolic (bias, +36.6 +/- 35 ml) and telediastolic volumes (bias, +35.6 +/- 35 ml) were overestimated. We conclude that AQ is a reliable technique, able to estimate CO precisely in patients with severe congestive heart failure. On the other hand, both telesystolic and telediastolic volumes were overestimated.