Tissue Doppler imaging in the left ventricle and right ventricle in healthy children: normal age-related peak systolic velocities, timings, and time differences

摘要

Tissue Doppler imaging (TDI) enables assessment of velocities and timings within the left (LV) and the right (RV) ventricle with high temporal resolution. Knowledge on normal age-related values of peak systolic velocities and timings in healthy children may optimize the benefit of device-based therapies in paediatric patients with heart failure. A total of 123 healthy children (from 1 month to 18 years old) underwent TDI evaluation of the RV and LV. Peak systolic velocity and time to peak systolic velocity were assessed at the basal LV lateral wall, inter-ventricular septum (IVS), RV free wall (RVFW), and at the RV outflow tract (RVOT). Intra-ventricular time differences were calculated. Regression analysis was performed to assess the age dependency of the ventricular mechanics. Median peak velocities were: LV lateral wall: 6.3 cm/s (inter-quartile range (IQR): 5.1-7.9 cm/s); IVS: 6.0 cm/s (5.4-6.7 cm/s); RVFW: 10.2 cm/s (8.9-11.3 cm/s); RVOT: 7.2 cm/s (6.0-8.2 cm/s). Timings of peak systolic velocities were: LV lateral wall: 101 ms (91-112 ms); IVS: 114 ms (100-128 ms); RVFW: 177 ms (157-194 ms); RVOT: 100 ms (88-113 ms). Timings and peak velocities significantly increased with age at both ventricles. No relevant time difference was observed within the LV, whereas a considerable time delay was observed within the RV between the RVFW and the IVS (62 ms, IQR: 45-74 ms) and between the RVFW and the RVOT (74 ms, IQR: 59-93 ms). The present evaluation provides TDI-derived physiological values on normal LV and RV mechanics of healthy children. Within the LV, no relevant time difference was observed, whereas a considerable mechanical delay is observed within the healthy RV.