There is no guarantee against heart attack much like there is no guarantee against getting struck by a bus when crossing the street.
One thing I have been doing is journaling. Sifting through my thoughts of the why am I am suffering from this and what am I am doing to make it worse? What I've found is that I do this to feel guarded and prepared for what happened to my grandmother (she died of a heart attack). I constantly monitor my heart for any perceived misstep. In the end, I'm not helping myself , I'm making things worse.
I have found that positive self talk helps immensely. I've also begun telling myself " my heart is healthy, my heart is strong". I tell myself this over and over and over everyday. Eventually by thinking this it'll sink in and hopefully kick out some of the fear thoughts.
When the anxiety tries to take over, repeat, "I am OK!" I am OK!" and practice controlling your breathing at the same time.
Be well,
Kitt