Hi I have palpitations also since I was 26 years old ...I noticed first when I was pregnant with my last child more than 11 years ago.
I was put on betablockers,my ultrasounds came back negative.
I feel worst after eating and sometimes after going to the bathroom.
Every single Dr. I visited try to treat my palpitations with betablockers wich tipically are prescribed to patients with high blood pressure, in my case I have low blood pressure.
I finally decide to leave with it ...I have bad days but I have lots of good days "normal days".
Recently I found a chinese accupuncturist ...it really helps me it's been months since I had a palpitation ..try you have nothing to loose!
Good luck