PP-009 Postnatal outcomes of newborn infants with fetal supraventricular tachycardia

AimFetal supraventricular tachycardia (SVT) occurs approximately 1 per 1000 pregnancies and is an important cause of morbidity and mortality. Maternally administered transplacental antiarrhythmics for fetal SVT can be effective, however, 51% to%60 of infants may develop postnatal SVT and postnatal outcomes may be quite different. Therefore, we aimed to identify postnatal outcomes of newborn infants with fetal SVT.Material and MethodA retrospective observational study was carried out from 2023–2024 at a tertiary perinatal and neonatal unit with fetal and pediatric cardiology on 2 cohorts; fetal SVT (Group 1) and postnatal SVT cohorts with no history of fetal SVT(Group 2).ResultsSVT was observed in 8 infants, 4 in each group. In Group 1, 3 out of 4 infants (75%) were male whereas in Group 2 sex ratio was equal. No substantial disparity was observed in gestational weeks (GW) or birth weights (BW) between the groups. None of the infants developed hydrops, ventricular dysfunction, pericardial effusion, or mitral regurgitation. The most common transplacental antiarrhythmics were digoxin and flecainide. 50% of infants in the fetal diagnosis cohort had SVT after delivery, one on day 1 and the other on day 8.ConclusionsAlthough the sample size was too small to perform effective analysis, these data can be used for clinical decisions and parental counseling in newborns with a history of fetal SVT.