Mary
I had this problem for a long time and no one seemed to know what it was..I also had a heart murmur at birth.....this doctor finally diagnosed it as a heart valve problem; the valve that pumps the blood either to or from heart doesnt always close properly allowing more blood to come through and causing the rapid heart beat...You might want to have that checked...he put me on blood pressure medicine even though I didnt have high blood pressure and that helped the problem.