My Husband, His Grandfather And Great Grandfather Died In Their

My husband, his grandfather and great grandfather died in their 50's from the widow maker.
What are the chances my son will inherit this?'the chances my daughter will inherit it?
Is there a genetic test that would tell us so?
What advanced testing is necessay? My son is 22, my daughter 17.
My son had an abnormality on his ekg which the dr was not at all concerned about. Is it possible to not be concerned about it or am I being s worried Jewish mother?!?
Many thanks.