[Study of variations in preload on the new echocardiography parameters of diastolic function in health subjects]

The standard Doppler indices of transmitral filling are changed by variations in preload, relaxation and left ventricular compliance. Recent work in the literature suggests that the new parameters of diastolic function [mitral flux propagation speed in colour TM. (Vp) and tissue Doppler mitral ring velocities (Ea)] are independent of loading conditions. The objective of this work was to study the effect of modifications in the preload on Vp and Ea in normal subjects. Therefore, we have studied various Doppler echocardiographic measurements performed at rest, during a Trendelenberg manoeuvre at 60 degrees, and after sublingual administration of trinitrate in 25 healthy young (2 +/- 8 years) male volunteers. The end diastolic volume increased from 126 +/- 25 ml in the resting state to 145 +/- 24 ml during the Trendelenberg (p = 0.009) then decreased after trinitrate to 121 +/- 28 ml. The peak of the E wave increased from 88 +/- 12 cm/s in the resting state to 90 +/- 15 cm/s during the Trendelenberg and decreased to 70 +/- 11 cm/s after trinitrate (p < 0.0001). The peak Ea annular velocities of the septal and lateral walls were 22 +/- 4 cm/s and 15 +/- 1.6 cm/s in the resting state, without variation during the Trendelenberg (22 +/- 5 cm/s and 15 +/- 2 cm/s) but with a significant reduction after trinitrate to 19 +/- 5 cm/s and 13 +/- 2 cm/s (p = 0.02 and p = 0.002). In contrast, no significant variation was noted in Vp (60 +/- 14 cm/s in the resting state, 62 +/- 12 cm/s during the Trendelenberg and 59 +/- 14 cm/s after trinitrate). We conclude that Vp is not significantly affected by preload whereas Ea is not independent of the loading conditions.