Purpose: To construct biventricular reference ranges for isovolumic time intervals (isovolumic contraction time, ICT; isovolumic relaxation time, IRT) and ejection time (ET) for colour tissue Doppler imaging (cTDI) between 15 and 37 weeks' in healthy fetuses.
Methods: This was a prospective multicentre cross-sectional study involving 160 singleton pregnancies between 15 and 37 weeks of gestation, using cTDI. ICT, ET, IRT and myocardial performance index (MPI) were analysed offline using a small region of interest (ROI) within the basal part of the right and left ventricular wall immediately distal to the annulus. Regression analysis was used to determine gestational age-adjusted reference ranges and to construct nomograms for cTDI parameters.
Results: Right and left ventricular ICT (p = 0.004 and p < 0.001) and ET (p = 0.011 and p = 0.050) increased, whereas IRT (p = 0.862 and p = 0.067) and MPI (p = 0.476 and p = 0.777) remained constant with gestational age.
Conclusions: This is the first study to evaluate fetal isovolumic time intervals in the second and third trimesters of gestation using cTDI. Normal data for fetal isovolumic time intervals and biventricular MPI by colour tissue Doppler imaging are provided. The reference ranges may be useful in research or clinical studies and can be used in fetuses with compromised cardiac function.
Keywords: Fetal colour tissue Doppler imaging; ICT; IRT; Isovolumic time interval; MPI; cTDI.