Worried! EIF at anatomy scan

Had my anatomy scan today and was told all was normal except they found a EIF in one of his heart chambers. I had the progenity NIPT done at 10 weeks which came back low risk and the NT scan which also looked good at 12 weeks. The nurse said this could be a soft marker for downs and are sending me to a level II ultrasound in 2 weeks. Anyone have any experience or words of encouragement???