Persistent right umbilical vein

Hi, i had my 20 week anatomy scan today & baby was 100% healthy. They did find something called “ Persistent right umbilical Vein” which they want me to come back in 3 weeks so baby can have a echocardiogram exam. The doctor told me plenty of times that baby is healthy and since it’s the umbilical cord that will be cut anyways not to worry but I’m definitely freaking out! Everything else was perfect. Has anyone had this happen? Baby girl was as active as can be but I can’t stop thinking about it. I also had negative genetic tests so she said that was good. Any nurses or mamas that can give me some advice??