My name is Brankovic, am I an heir to the medieval house of Brankovic?
No, of the Serbian medieval nobility there are no documented direct heirs. It is possible that you are in some way related to medieval nobility, but as we have mentioned several times, thurough genealogical research must be done to be able to bring any such conclusion. Your name probably derived from an ancestor who adopted a surname. In this case, it would be Branko.