When I was in my early 20's, I was diagnosed with Mitral Valve Prolaps. (That valve doesn't pump blood to and from my heart) I would have symptoms like you described. The Dr. told me at that time that if you were to put 10 people in a room, one out of 10 would have MVP. He prescribed Inderal for me to take and for almost 30 years, I took 20 milligrams of Inderaldaily for MVP.
A year ago, I started reading about magnesium and realized it could help my heart better than Inderal. So, I weaned myself off the Inderal. Now, I just take a little Epsom Salt everyday. My heart beats normally.