Cardiac hemodynamics in fetuses with transposition of the great arteries and intact ventricular septum from diagnosis to end of pregnancy: longitudinal follow-up.

OBJECTIVES: Little is known about cardiac hemodynamics in the fetus with transposition of the great arteries and intact ventricular septum (TGA-IVS). Better understanding of the fetal physiology in TGA-IVS would help to provide insights into specific clinical complications observed after birth, in particular neonatal hypoxia and pulmonary hypertension. The aim of this study was to assess cardiac hemodynamics in fetuses with TGA-IVS by performing systematic longitudinal echocardiographic follow-up from diagnosis to delivery. METHODS: This was a longitudinal retrospective study of fetuses referred between 2010 and 2018 to the Sainte-Justine University Hospital Centre. Complete assessment of cardiac hemodynamics was performed in fetuses with TGA-IVS at 18-22, 28-32 and 35-38 weeks' gestation, which were compared with normal fetuses matched for gestational age. The maximum diameter of the foramen ovale was measured using two-dimensional echocardiography under the guidance of color Doppler echocardiography. Fetal cardiac hemodynamics were analyzed according to postnatal preductal transcutaneous oxygen saturation (TcSO2 ) < 65% or ≥ 65%, as a neonatal outcome, in fetuses with TGA-IVS. RESULTS: In total, 59 fetuses with TGA-IVS and 160 normal fetuses were included. Global cardiac output was significantly higher in fetuses with TGA-IVS than in controls, mainly owing to higher global pulmonary output, while global systemic cardiac output did not differ between TGA-IVS fetuses and controls throughout pregnancy. Aortic flow (right ventricular output in fetuses with TGA-IVS, left ventricular output in controls) was significantly higher in fetuses with TGA-IVS than in normal fetuses. Ductal flow was significantly lower in fetuses with TGA-IVS at every timepoint, and this difference increased considerably after 28-32 weeks. In parallel, the diameter of the foramen ovale was significantly smaller in fetuses with TGA-IVS at 28-32 and 35-38 weeks, with a stagnation in growth after 28 weeks, compared with continuous growth in normal fetuses. Most of these cardiac hemodynamic anomalies in fetuses with TGA-IVS were already present at 18-22 weeks, and the differences became greater at 28-32 weeks' gestation. TGA-IVS neonates with TcSO2 < 65% had lower fetal left ventricular output, higher diastolic ductal retrograde flow and smaller foramen ovale at 28-32 weeks, compared with fetal values in those with postnatal TcSO2 ≥ 65%. CONCLUSIONS: Compared with normal fetuses, those with TGA-IVS undergo a complex redistribution of blood flow during the second half of pregnancy, with higher global pulmonary flow, lower ductal flow (with negative diastolic flow at the end of pregnancy) and a smaller foramen ovale. In addition, fetal cardiac hemodynamic anomalies observed at 28-32 weeks' gestation were associated with lower postnatal TcSO2 . These observations may provide a better understanding of premature closure of the foramen ovale and postnatal hypoxia that are specific to TGA-IVS physiology. © 2019 International Society of Ultrasound in Obstetrics and Gynecology.

Enhanced EEG connectivity in children with febrile seizures.

BACKGROUND: Epilepsy is currently conceptualized as a disturbance of neuronal networks with altered connectivity that persists into the interictal phase. Febrile seizures are sometimes a precursor in childhood of lifelong epilepsy. We investigated whether studying functional connectivity in children with febrile seizures could help understand the mechanisms underlying their long-term seizure susceptibility. METHODS: EEG was recorded during rest and intermittent photic stimulation (IPS) in 12 FS patients, 5 siblings and 15 control children between 6 and 36 months of age. Original EEG data were transformed into source space using a multiple regional source model. Source coherence values were calculated for the interfrontal, interoccipital and occipito-frontal connections for the delta, theta, alpha, beta and gamma frequency bands. RESULTS: Our results suggest enhanced delta and theta frequency EEG source coherence in patients with FSs compared to siblings and control children, both under resting conditions and during IPS, more consistent for the theta band and the occipito-frontal connections. CONCLUSIONS: Enhanced connectivity in patients with FSs could indicate a seizure-prone state and interfere with the maturation of cerebral networks. Further prospective studies are needed to assess whether hyperconnectivity is a risk factor for epileptogenesis and neurodevelopmental disorders.

Children with a history of atypical febrile seizures show abnormal steady state visual evoked potential brain responses.

Atypical febrile seizures (FSs) are considered a risk factor for the onset of epilepsy in later life as well as for potential cognitive impairment. However, distinctive characteristics defining the group of children at risk for negative outcomes are not well established. In the following study, children from 6 to 59 months with a history of atypical FSs were investigated using steady state visual evoked potentials (ssVEP), a brain response known to increase with age. Abnormally, low theta and alpha ssVEP brain responses were found in children with a history of atypical FSs.

Interaction between the flash evoked SSVEPs and the spontaneous EEG activity in children and adults.

OBJECTIVE: To evaluate the interaction between the steady-state visual evoked potentials (SSVEPs) recorded during the intermittent photic stimulation (IPS) and the spontaneous EEG activities both in children and adults. METHODS: EEG was recorded during the rest and under 5, 7.5, 10 and 12.5 Hz IPS in 41 children between 3 and 16 years and 10 adults. We distinguished between the spontaneous resting EEG spectra, SSVEPs (1st harmonic) and undriven (ongoing) EEG spectra recorded during the IPS. RESULTS: We show that IPS influences spontaneous EEG activity by specifically suppressing or desynchronizing individual posterior dominant resting EEG frequencies (DF) in both children and adults. Further, this highly significant and consistent suppressing effect positively correlates with the SSVEPs amplitude. CONCLUSIONS: Our data suggest that the desynchronization of the spontaneous EEG activity under IPS and the SSVEPs are related to each other. SIGNIFICANCE: These relationships could be interesting to study in pathological conditions where the neural synchronization and the responses to IPS have been shown to be affected, such as epilepsy and schizophrenia.