I too have suffered from anxiety for years - for almost 20 years was on/off imipramine (25mg/day) and heartrate was always in high 80's to low 90's, no other side effects
and it was working, but after time blood pressure
started to go up. Dr. changed me to lexapro
(gained a little weight), blood pressure went back to normal - usually runs around 102/68, but my heartrate has now dropped to the 50-60's which is freaking me out more.