Diastolic Filling and Pressure Imaging: Taking Advantage of the Information in a Colour M-mode Doppler Image

Abstract

The ability to derive non-invasively information on left ventricular diastolic function on one hand and pressure gradients on the other hand, makes Doppler ultrasound a very attractive tool in clinical practice. However, the limitations of the standard Doppler approaches in differentiating between normal and pseudonormal filling patterns, together with the limitations of the simplified Bernoulli equation for assessing pressure gradients, are well described. In this manuscript the role of colour M-mode Doppler echocardiography as a tool that can overcome these limitations is discussed. Relevant key concepts of the haemodynamics of left ventricular filling and its relationship with colour M-mode Doppler echocardiography are introduced.

Assessment of LV diastolic filling using color M-mode Doppler echocardiography: validation in a new hydraulic model

“…The formation of a ring vortex during LV filling is predicted by numerical (Iudicello et al 1997;Vierendeels et al 2000) and in vitro simulations Shortland 1996;Steen and Steen 1994) and is in agreement with in vivo observed characteristics of LV filling Vierendeels et al 2002). Therefore, a v p value obtained from a CMD image can be associated with the propagation velocity of the ring vortex from the base towards the apex (Steen and Steen 1994;Vierendeels et al 2000;De Mey et al 2001;Vierendeels et al 2002). A convincing argument in our (and previous) observations is that E always exceeded v p , which agrees with the hydrodynamic principle that, due to the intrinsic circular motion of the particles in the ring vortex, the velocity of particles (E) in a vortex ring exceeds the velocity at which the whole ring travels (v p ).…”

“…In the quest to differentiate between normal and pseudonormal LV filling patterns, different pathways have been followed (De Mey et al 2001). In this study we focused on v p as measured using CMD echocardiography.…”

“…Intracavitary flow patterns can be studied using color Doppler M-mode echocardiography (CMD), which captures velocity profiles at several locations along a scanline simultaneously (De Mey et al 2001). From the intracavitary velocity field, the speed at which the bloodvelocity wave is propagating towards the apex (the flow propagation velocity, v p ) can be derived (Brun et al 1992;Stugaard et al 1993;Takatsuji et al 1996).…”

Computational study on the evolution of an intraventricular vortical flow during early diastole for the interpretation of color M-mode Doppler echocardiograms

“…Since then, CMD echocardiography and the CMD-derived parameter ''flow propagation velocity'' have attracted the attention of cardiologists as a new method to evaluate diastolic function of the LV. Five different approaches (Brun et al 1992;Stugaard et al 1993Stugaard et al , 1997Takatsuji et al 1996;Duval-Moulin et al 1997) have been used to obtain flow propagation velocity from a color M-mode Doppler echocardiogram (De Mey et al 2001). Although these studies have shown the usefulness of CMD echocardiography for assessing LV filling flow, because of the complexity of the pattern of blood flow in the LV as well as the limited amount of information obtained by using these methods, theoretical bases of the relationship between pattern of a CMD echocardiogram and LV diastolic function have not been elucidated.…”

Effect of flow disturbances remaining at the beginning of diastole on intraventricular diastolic flow and colour M-mode Doppler echocardiograms

“…The measured velocity is presented in an M-mode image called a CMD echocardiogram. Evaluation of LV diastolic function is made based on a CMD echocardiogram colour pattern (DE MEY et al, 2001).…”