What are the chances of this happening to my dog....Breeders help with genetics?

Having a sister (I'm uming full blooded) with this condition is bad- I would contact your vet or a local breed club and see if they can recommend a heart clinic. There are vets who can do a screening for this type of disease. We had our puppy tested at about 8 or 9 months. The results couldn't be certified and recorded because he was too young, but it was enough to give us peach of mind. It would pick up any genetic heart disorders.