[Doppler tissue imaging of the myocardium and right ventricle]

Doppler tissue imaging is a technique of analysis of myocardial wall motion. It may easily be used for the right ventricular walls, especially in the apical 4-chamber view, from which the velocities of the RV free wall can be measured from the tricuspid annulus to the apex. The regional velocities of the right ventricle in its long axis and the excursion of the tricuspid annulus are higher than those of the left ventricle but the velocities of circumferential fibre shortening are lower. Moreover, the time interval between the end of the Sm wave and the onset of the Em wave (equivalent to the isovolumic relaxation time) is almost virtual in the right ventricle. The parameters of deformation (strain rate, strain) are also higher in the right than in the left ventricle and are variably distributed. Several studies have examined the clinical value of Doppler tissue imaging of the right ventricle. In cardiac failure, a significant correlation between the systolic velocity of the tricuspid annulus displacement and right ventricular ejection fraction has been reported. The ratio of tricuspid E wave velocity to the tricuspid annulus B wave allow assessment of right ventricular filling pressures. The measurement of tricuspid annulus velocities could be diagnostic of right ventricular extension of an inferior wall infarct. The recording of a "rebound" positive wave just after the E wave in the RV and LV free walls (and in the interventricular septum) is a diagnostic sign of constrictive pericarditis. Doppler tissue imaging is therefore a promising technique for evaluating right ventricular function.