Hey Tina, I was also prescribed Atenonol for racing heart after EKG and Echo. It did help alot with the racing heart but my blood pressure was not staying stable on it so I was recently switched to Coreg.
Bi-polar is a pretty big diagnosis. Is the DR your PCP or phychatrist? I always thought Bipolor showed itself at a fairly young age. From the people I know that are bipolar, they have high highs and low lows. I would suggest doing some research on it before accepting that diagnosis as the root of your problems.
Best Wishes,

JB