Assessment of left ventricle preload by transthoracic echocardiography: an easy task?

In sicker hearts, right atrial pressure (an estimation of right ventricle preload) are not equivalent to left atrial pressure (an estimation of left ventricle preload). Both right and left atrial pressures are frequently estimated using invasive techniques and also transthoracic echocardiography. While right atrial pressure is easy to obtain with transthoracic echocardiography, the assessment of left ventricle preload or filling pressures is not simple. In relation to the study of Sasai et al. (J Intensive Care 2(1):58, 2014), this paper discusses in a succinct manner how to think and assess the left ventricle preload by transthoracic echocardiography.