Evaluation of fetal left cardiac function by Tei index at different cardiac cycles: An observational study

The Tei index is widely used to evaluate fetal left cardiac function; however, its clinical application is limited by technical difficulties and inconsistent methodology. This study aimed to validate a new method for measuring left cardiac Tei index using Doppler waveforms obtained from different cardiac cycles and to assess its accuracy, rapidity, and reproducibility, as well as technical considerations of the conventional method.

This study was a retrospective observational analysis including 50 healthy singleton pregnancies between 22 and 39 weeks of gestation. All fetuses had structurally normal hearts and sinus rhythm. Two certified obstetricians consecutively performed both the conventional measurement at the same cardiac cycle and the new measurement at different cardiac cycles. Consistency with reported normal ranges, interobserver variability, and measurement time were compared, and technical factors such as maternal BMI and insonation angle were also evaluated.

Tei index values obtained from different cardiac cycles did not differ significantly from those obtained using the conventional method and were generally within normal ranges. Interobserver variability showed no significant difference. Measurement time was significantly shorter at different cardiac cycles. Values remained stable regardless of BMI, and the most consistent measurements were obtained at an insonation angle of ≈45°.

Tei index measurement at different cardiac cycles provides accurate, rapid, and reproducible assessment of fetal cardiac function. This method may support early detection of dysfunction and assist in determining optimal timing of delivery. The insonation angle may influence measurement difficulty more than maternal BMI.