Reference ranges for left, right and interventricular septum indices at 20 to 36+6 weeks of gestation derived using spectral myocardial tissue Doppler on Voluson ultrasound machines.

Abstract

To establish reference range values for peak myocardial tissue Doppler velocity (MTD) and myocardial performance index (MPI) of the left ventricle (LV), the right ventricle (RV), and the interventricular septum (IVS) at 20 to 36+6 weeks of gestation using spectral tissue Doppler. This cross-sectional study was conducted among 360 lowrisk singleton pregnancies. MTD during systole (S'), and early (E') and late diastole (A'), and MPI' were assessed by placing sample volume at the basal segment of the LV free wall, the RV free wall, and the IVS, respectively. Polynomial regression was used to obtain the best-fit curves for MTD and MPI' measurements as a function of gestational age (GA), and adjustments were made using the determination coefficient (R2). Intra- and inter-observer reproducibility was evaluated using the concordance correlation coefficient (CCC). All MTD velocities (cm/s) progressively increased with advancing GA (p<0.0001). Mean LV MTD values were 4.19 to 6.86 for S', 3.52 to 7.22 for E', and 6.85 to 9.19 for A'; mean RV MTD were 4.85 to 7.97 for S', 4.49 to 8.66 for E', and 8.44 to 11.20 for A'; and mean IVS MTD values were 3.75 to 5.78 for S', 3.34 to 5.79 for E', and 5.88 to 7.98 for A'. LV MPI', RV MPI', and IVS MPI' did not significantly change with advancing GA. The CCC values for MTD were predominantly greater than 0.70, while those for MPI' were <0.70. Reference values for the fetal MTD and MPI' of RV, LV and IVS using tissue Doppler between 20 and 36+6 weeks of gestation were described.