P22.01: Novel technique to detect fetal heart rate automatically using two‐dimensional speckle‐tracking echocardiography

Abstract

Although it is ideal to avoid using pulsed Doppler in the first trimester for the safety, it is inevitable to use current available ultrasound technique, pulsed Doppler or M-mode echocardiography, to measure fetal heart rate. We developed novel technique to assess fetal heart motion by using two-dimensional speckle-tracking method and validated the feasibility of automated fetal heart rate (FHR) calculation using this technique. Normal singleton fetuses were selected for the study. Feral heart was visualized and then the heart motion was recorded by conventional two-dimensional ultrasonography for the analysis. Square-shaped region-of-interest (ROI) was placed on the fetal heart. The outer squares of 3x3 grid within ROI were used for tracing the heart itself and the central square of ROI was analyzed to calculate FHR. Cyclic changing pattern of central square was calculated automatically and used for counting FHR (AutoFHR). Furthermore, AutoFHR was compared with FHR derived from conventional M-mode echocardiography. Total 48 singleton fetuses were eligible for the study and single analysis was done in each fetus. Mean gestational age at analysis was 30.0 ± 6.8 weeks of gestation. The tracing of fetal heart during fetal gross movement was possible and AutoFHR could be calculated. AutoFHR was significantly correlated with FHR by M-mode echocardiography (R = 0.880, P < 0.05). Inter-observer and intra-observer variability (%CV) were 1.2 and 2.2, respectively. AutoFHR was possible even in early first trimester (7 weeks of gestation). AutoFHR was novel technique to calculate FHR by not using Doppler ultrasound or M-mode echocardiography. This novel technique would make it easier and safer to detect fetal heart rate than conventional pulsed Doppler technique.