Evaluation of Right Ventricular Contraction by Myocardial Strain in Children Using a Two-Dimensional Tissue Tracking Method

Two-dimensional tissue tracking makes it possible to detect myocardial strain in any direction. Consequently, this method is applicable for evaluation of myocardial dyssynchrony. This study enrolled 22 healthy volunteers (11 boys and 11 girls) ages 1.6 to 10.8 years (mean, 6.8 years). Echocardiography (subxiphoid right anterior oblique view) of the right ventricle was examined. Three tracking points were put on the right ventricle, and time-strain curves of the inflow tract (strain at the inlet) and the outflow tract (strain at the outlet) as well as time-strain curve of the pulmonary annulus diameter were made. The strain at the inlet was larger than the strain at the outlet (0.31 vs 0.15; p = 0.0003). The time to peak negative strain at the inlet was longer than at the outlet (0.48 vs 0.42 s; p = 0.001). The diameter of the pulmonary annulus shortened in systole, and the time to peak negative strain of the pulmonary annulus was longer than that of the outlet (0.48 vs 0.42; p = 0.001). There was no significant difference in the times between the pulmonary annulus and the inlet (0.48 vs 0.48; p = 0.78). Two-dimensional tissue tracking allows assessment for quantification of myocardial performance and timing of the right ventricle.