Heart problams in the family...should I worry?

I am a 16 year old girl. Last year my dad died from problems with his heart. He was only 41. A couple of years before that, my nana(my dads mom) died from a heart attack. She was in her early fifties. They both died young from heart problems. My dad had 2 older brothers who are both fine. I was wondering if it was hereditary. If it is, what can I do to prevent it?