I can only share my experience.

loads of times now I have been to the hospital, had doctors out, etc etc, because I feel that i'm having a heart attack

they have constantly said to me your heart's fine, you're heart's fine- if it was a heart attack, we'd know. it's just your anxiety
it reasures me for a while, but then I get the same fear- and I know I need to stop this because it's wasting valuable time of the hospital staff

last year they spent a whole day doing tests on my heart for absolutely nothing