My personal oppinion is that Anxiety is a easy diagnoises and used as test people but I thinks its a horrible test(if that what it is) and it's a lazy diagnoises. It should never be diagnoised unless other test have been done first to rule other more serious problems out.
I also dont think that anxiety could ever cause an extreamly high heart rate at all and even if anxiety can do that if some one is dealing with a high heart lots. There entitled to have some releif even if the tachy issues is not dangerous. Quality of life is JUST as important as good heath and I think some time Dr's forget that.
Are you sure that anxiety can never make the HR go to 160 or more?
6 months back I used to still have panic attacks (and hyperventillation),and i think i went to 180 and possibly 200 multiple times those days.
In my experience SVT isn't cured with Xanax or anything to do with panic. they are two completely different things. The SVT is an electrical problem and the anxiety has to do with the neruotransmitters. I was told SVT attacks can range anywhere above 160 BPM but no anxiety attack could ever mimic that (usually plateau at 140).
Panic is cauased by excess adrenaline in your system, some help can be gained from yoga, meditation, therapy, stress management, and good nutrition.
The Xanax treats the anxiety/panic. It is highly addictive and I would see a doctor for a better way to treat it, possibly a beta blocker, which would help BOTH the SVT and the panic.
Anxiety causes the panic attack.