P.S. Sorry to hear that you are suffering with "prolonged" panic attacks. I totally agree with S.C. about
the peaking in 10 minutes thing. I have NEVER had a panic attack stop after 10 minutes. I don't know where these people get their info, but people who really suffer from them know different.
The problem for me lies in the residual anxiety that we have AFTER getting over the initial panic attack. It tends to put our self awareness into overdrive, so any physical symptoms we experience with our bodies is magnified and causes us stress if we think it's not normal. This in turn will cause repeated attacks because we are getting ourselves so "worked up" by the sensations we are feeling in our bodies. Then before we know it, BAM! here's another panic attack, so we stress over having another one, and another, and so on.... It creates a vicious cycle!
You have to tell yourself that it's only a panic attack, it will go away. You have had how many already, always made it through them ALIVE, and you will this time also. I know how distressing it can be. I was to the point I was having them every day, all day long. They have pretty much subsided for me since going back on my medications though.
Are you seeing a psychiatrist, therapist, or counselor? Or taking any medications? If not, i'd suggest, like so many others here, doing deep breathing exercises. They are VERY helpful, especially to eliminate palpitations, that can be so scary for all of us. It calm your heart rate, and makes you feel relaxed.
I hope you start feeling better soon! Fox