Help please! is asd (atrial septal defect) a hereditary condition?

Yes (in a sense): We are only just beginning to understand the genetics of congenital heart disease (chd). There are some specific genetic syndrome associated with asds. In addition, simply having an ASD does impart an increased risk--though small--of having children with chd. So yes, having chd is heritable, but in a multifactorial way (i.e. Not a single gene defect in many cases).