Fetal Heart Remnants: Understanding the Foramen Ovale and Ductus Arteriosus

Two fetal cardiac structures may persist after birth:

1. Foramen ovale: Opening between right and left atria allowing oxygenated placental blood to bypass fetal lungs. Normally closes after birth; if it remains patent (PFO), it's usually asymptomatic but can allow paradoxical emboli.
2. Ductus arteriosus: Vessel connecting pulmonary artery to aorta, shunting blood away from lungs. Normally closes after birth; persistent patency (PDA) is a congenital heart defect requiring intervention.