Fetal Ebstein Anomaly
Severe Ebstein can be associated with circular shunt physiology, in which the blood flow enter the Pulmonary Artery via the ductus arteriosus, following which it returns to the RV by significant pulmonary insufficiency. The blood flow then enters the right atrium secondary to tricuspid valve insufficiency and to the left atrium via the patent foramen ovale. Following which, it enters the left ventricle (LV) and is pumped into the aorta, to eventually re-enter the ductus arteriosus. This physiology leads to a low cardiac output state and may compromise organ oxygenation.
Circular shunt physiology in Ebstein: Aorta → Ductus → Pulmonary artery → Pulmonary Insufficiency → Right Ventricle → Tricuspid insufficiency → Right atrium → Foramen Ovale → Left atrium → Mitral valve → Left ventricle → Aortic valve → Aorta → Ductus arteriosus (Learn more here, and here). Some have described the use of maternal NSAIDs as a way to constrict the fetal duct in an attempt to address this fatal physiology for the fetus / newborn. Article here on "Surgical Management of Neonatal Ebstein’s Anomaly Associated With Circular Shunt".
Downward displacemet of the tricuspid valve indicating Ebstein.
Significant tricuspid insufficiency in the context of Ebstein.