EP09.45: Decreased biventricular longitudinal function in tetralogy of Fallot fetuses by speckle tracking echocardiography

To define the pattern of cardiovascular remodelling and function in tetralogy of Fallot (ToF) fetuses by speckle tracking echocardiography (STE). A multicentric prospective study was conducted from 2011 to 2023. We included 63 isolated ToF fetuses evaluated at the cardiology unit of BCNatal and University Hospital of Giessen and Marburg in Germany. Cases were matched to 66 low risk pregnancies followed at BCNatal. A speckle tracking analysis from 4-chamber view clips was performed in all participants to evaluate morphometry and function. Among the 63 ToF fetuses, 5 had pulmonary atresia, with retrograde ductus arteriosus flow at echocardiography, and the rest were ToF with pulmonary stenosis. There were no significant differences between both groups in terms of maternal baseline characteristics except for maternal body mass index, which was higher in the ToF group. A higher rate of placental diseases such as pre-eclampsia (6.35%) and fetal growth restriction (19.1%) was also identified in the pregnancies with TOF fetuses. Median gestational age was at ultrasound was similar between groups (31.6 weeks). ToF fetuses show signs of cardiac remodelling with a lower sphericity index. In terms of RV contractility, a significant decrease in RV GLS and TAPSE was observed (GLS: ToF -17.25 ± 3.76% vs controls -19.33 ± 3.09%; p= 0.001; TAPSE: ToF 4.77 ± 1.68mm vs controls 5.90 ± 1.71mm; p = 0.032), while FAC remained within normal ranges. Additionally, there was evidence of impaired LV deformation, as indicated by significantly lower LV GLS, LV EF, and MAPSE (ToF-17.96 ± 3.78% vs controls - 20.87 ± 3.45%; p= 0<.001; EF: 41.01 ± 11.90% vs controls 49,44 ± 10.30%; p = 0.001; MAPSE: ToF 4.09 ± 1.79mm vs controls 5.45 ± 1.60mm; p =< 0.001). ToF present higher incidence of placental diseases and signs of cardiovascular remodelling from prenatal life, characterised by a more spherical heart with lower biventricular deformation.