Temporal Sequential Pattern of Right Ventricular Free Wall Contraction in Normal Children.

Abstract

The temporal sequence of right ventricular (RV) deformation is related to RV dysfunction. The sequence of RV free wall contraction was investigated.Methods and Results:In this prospective study, strain profiles using speckle-tracking echocardiography and tissue Doppler-derived pulmonary and tricuspid annular motion were assessed in 60 normal children. Circumferential RV free wall strain of 3 individual segments (anterior, lateral, and inferior) was evaluated. Longitudinal strain was assessed in 3 individual segments (RV outflow tract [RVOT], apical, and RV inflow tract [RVIT]). The isovolumetric contraction time (ICT) and the time interval between the onset of the QRS wave to the peak s' wave were measured for pulmonary and tricuspid annular motion velocities. The time to peak circumferential strain was significantly lower in the anterior than in the lateral and inferior segments (339.1±19.5, 358.3±21.8, and 366.6±22.4 ms, respectively; P<0.0001). Longitudinal deformation of the RVOT segment occurred before the apical and RVIT segments (351.8±23.1, 366.3±20.1, and 369.2±21.3 ms, respectively; P<0.0001). The ICT and the time to peak s' were significantly shorter in pulmonary than in tricuspid annular motion (49.4±10.1 vs 58.0±13.2 ms; and 104.7±12.2 vs. 160.5±27.1 ms; P<0.0001 for each). Longitudinal deformation of RVOT precedes RVIT. Circumferential deformation occurs in the anterior segment before the lateral and posterior segments. The presence of mechanical time heterogeneity appears important for RV performance.