Echocardiographic methods for quantification of left ventricular ejection fraction: are they interchangeable?

This study examined the relationships between left ventricular ejection fraction data derived from four commonly used cardiac ultrasound measurement methods (visual estimation, wall motion scoring, biplane Simpson's method and three-dimensional [3D] echocardiography) to assess whether they can be used interchangeably in the assessment of left ventricular systolic function. Two-dimensional (2D) and 3D data obtained from ultrasound studies for 190 patients (109 men, mean age 56 +/- 20 standard deviation [SD] years [range 20-87] and 81 women, mean age 61 +/- 18 SD [range 23-96]) with routine cardiac referrals were analysed. Ejection fractions were estimated for each patient offline using standard 2D echocardiography for visual estimation, wall motion scoring and biplane Simpson's methods, while 3D data were analysed using Phillips 3DQ Advanced software. Bland-Altman analysis was performed to test the agreement between the different measurement techniques allowing determination of significance, bias and 95% limits of agreement. Bland-Altman plots were also used to further investigate whether agreement between methods varied with different levels of left ventricular function. Only two method comparisons (visual estimation versus wall motion scoring and biplane Simpson's method versus 3D echocardiography) showed no statistically significant differences (P = 0.09 and 0.99) or bias (-0.7 and 0). However, the 95% limits of agreement were wide (-11.1% to 9.8% and -14.3% to 14.3%, respectively). Visual estimation, wall motion scoring, biplane Simpson's method and 3D echocardiography should not be used interchangeably for serial assessment of left ventricular ejection fraction.