Three-dimensional echocardiographic determination of left ventricular volumes and function by multiplane transesophageal transducer: Dynamic in vitrovalidation and in vivo comparison with angiography and thermodilution

The goal of this study was to validate 3-dimensional echocardiography by mu ltiplane transesophageal transducer for the determination of left ventricul ar volumes and ejection fraction in an in vitro experiment and to compare t he method in vivo with biplane angiography and the continuous thermodilutio n method. In the dynamic in vitro experiment, we scanned rubber balloons in a water tank by using a pulsatile now model. Twenty-nine measurements of v olumes and ejection fractions were performed at increasing heart rates. Thr ee-dimensional echocardiography showed a very high accuracy for volume meas urements and ejection fraction calculation (correlation coefficient, standa rd error of estimate, and mean difference for end-diastolic volume 0.998, 2 .3 mL, and 0.1 mL; for end-systolic volume 0.996, 2.7 mL, and 0.5 mL; and f or ejection fraction 0.995, 1.0%, and -0.4%, respectively). However, with i ncreasing heart rate there was progressive underestimation of ejection frac tion calculation (percent error for heart rate below and above 100 bpm 0.59 % and -8.6%, P < .001). In the in vivo study, left ventricular volumes and ejection fraction of 24 patients with symmetric and distorted left ventricu lar shape were compared with angiography results. There was good agreement for the subgroup of patients with normal left ventricular shape (mean diffe rence +/- 95% confidence interval for end-diastolic volume 5.2 +/- 6.7 mL, P < .05; for end-systolic volume -0.5 +/- 8.4 mL, P = not significant; for ejection fraction 2.4% +/- 7.2%, P = not significant) and significantly mor e variability in the patients with left ventricular aneurysms (end-diastoli c volume 25.1 +/- 56.4 mL, P < .01; end-systolic volume 5.6 +/- 41.0 mL, P = not significant; ejection fraction 4.9% +/- 16.0%, P < .05). Additionally , in 20 critically ill, ventilated patients, stroke volume and cardiac outp ut measurements were compared with measurement from continuous thermodiluti on. Stroke volume as well as cardiac output correlated well to thermodiluti on (r = 0.89 and 0.84, respectively, P < .001), although both parameters we re significantly underestimated by S-dimensional echocardiography (mean dif ference +/- 95% confidence interval = -6.4 +/- 16.0 mL and -0.6 +/- 1.6 L/m in, respectively, P < .005).