Thank you for your responses!
Normorcrazy - I drink at least 48oz of water every day, if not more, so I know it is not that. Thank you for the idea, though.
SRMom - I have seen many posts from you on this board and you seem to know all about this stuff. Can anxiety be responsible for this constant rapid heart rate? I really don't have much stress in my life, but I think I have acquired some health anxiety because of another medical problem I have that no one can seem to figure out (unrelated to my heart). My heart is always racing and pounding - even when I am just relaxing watching TV. Can it really be just anxiety?
My doctor actually put me on atenolol first and I almost passed out. I think it dropped my blood pressure too low. He said that bisoprolol is the weakest of all the beta blockers so that is why he put me on that. But you are right, I could probably stand a higher dose. This racing, pounding heartbeat is driving me absolutely insane! I wake up with it and go to sleep with it every single day. I'm afraid to do any type of physical activity, even though my doctor has told me I will be OK.
Thanks to both of you for your responses. It does help to talk to people that have had the same problems.