Gumby
I had the same issue about 10 months ago while recovering from a GI bleed
Afterwards, the bleeding stopped, and my Hemoglibin and Hematocrit started comning up, but my heart was racing all the time - Doctors thought it could be anxiety, the prednisone, etc...
They had me where a monitor and saw that while my heart rate was high, there was no issue with my heart.
After about a week, I looked really close at all my blood work.
One of the things I noticed was that my RBC was unusually low.
I have had GI bleeds (large bleeds -Lots of Black blood in the toilet) in the past, but Looking over my past 8 years of blood work, this is the first time that I noticed a low RBC.
When I looked into it, I saw that the symptoms of a low RBC- Rapid heart rate.
My issue is that I am on 6MP and this actually affects the bodies ability to recover RBC count. that being said...the heart rate issues subsided after about 3-4 weeks.
my RBC is still a little low (4.2) so the rapid heartrate doesn't bother me, although when I run, or do long term exercise, it does take my heart a little longer ot get down back into the 90's.
My Hemoglobin and HEmatocrit are now in range. I figure as long as I am on 6MP my RBC will be a little low.
Check you last CBC and see if your RBC is low.
If you want to talk about it let me know and I can give you my cell so we can talk.
I know I was really nervous the whole time I had it, and I also came to healing well, and got a lot of the same types of responses you are getting (where heart rate monitor, see a cardiologist, etc...)
Take care