s hard to say what causes the fast
heart rate.
For some reason, many of us have incidents that come and go
for no apparent reason. Hormones do seems to play a role for many women, not sure why (but not surprising...lol).
Were you referred for any followup?
As for the leg cramping, that could be from the medication....is your doctor aware of the cramping? If you have not had an echocardiogram (ultrasound of the heart), it might not be a bad idea.