Cardiologist diagnosed me with hypertensive heart disease. he said my children have a 40% chance of having it. can i do anything to prevent it?

Yes: So he is saying that when someone has HTN at a young age. It puts their children at higher same risk. Your children should be made aware of the risk, and they should eat healthy, exercise regularly and maintain a normal body weight....And no smoking. That will help reduce risk.

Let the family know: Let your children about the risk and ask them about the life style modifications.