ABSTRACT
Left ventricular (LV) dimensions, volumes, and wall thicknesses using echocardiography are widely used indices in clinical practice and trial.1 Although visual assessment is frequently used to assess LV size and systolic function, the accuracy depends on the observer’s skill. Thus, quantifi cation of LV size, systolic function, and mass using two-dimensional (2D) echocardiography has been recommended. The use of 2D methods for quantifi - cation of LV size, mass, and function has been validated in the previous studies.2-5
LV volume
In patients with LV wall motion abnormalities, LV volumes and ejection fraction (EF) are especially important for prognostic predictors and physiologic indices.6,7 LV volume and EF from linear dimensions from 2D images using Teichholz or Quinones methods may be inaccurate because they are based on geometric assumptions.8,9 The most commonly used method for volume measurements recommended by the American Society of Echocardiography is the biplane method of disks (modifi ed Simpson’s rule) (Figure 2.1).10 Because this 2D method minimizes mathematic assumptions, more accurate LV volume and EF can be assessed compared with Teichholz or Quinones methods from LV linear dimensions. The principle of this method is that the total LV volume can be calculated from the summation of elliptical disks. However, 2D methods still have technical limitations for LV volume measurement in patients with LV asynergy, especially with LV distortion. Underestimation of LV volume has been reported compared with angiography or magnetic resonance imaging (MRI).11-14 Errors in image plane positioning may be the most important problem in 2D echocardiography for the LV volume
estimation. The apex is frequently foreshortened in the apical views because of the diffi culty in obtaining an adequate apical echocardiographic window in most of the patients.11 Another limitation in 2D methods is that 2D echocardiography has still geometric assumptions because it can evaluate only four walls of the LV (anterior, inferior, lateral, and septum walls); wall motion abnormalities in the anteroseptum and posterior walls cannot be assessed in the recommended biplane method. In addition, signifi cant operator (different sonographers) and observer (different reading doctors) variabilities may be another limitation of 2D echocardiography, especially in serial studies.
