In Chinese medicine, anxiety and panic attacks are attributed to Kidney Deficiency typically. When the “Kidney energy” is out of balance we tend to have irrational fears. You can avoid a lifetime of medications by rebuilding the Kidney energy with tonic herbs, qi gong meditations, and acupuncture. Here is an article that explains:
http://www.agelessherbs.com/NaturalAnxietyHerbs... :

It depends on the person.

Try to notice what happens immediately before you experience one. Is it the same, or similar things? Does it have to do with the same person, or the same type of situation? Different things trigger panic attacks for different people, the trick is to discover what your own trigger is.

Good luck & Have a Great Day!
HK
References :

Excess stress or a fright causes a surge from a part of the brain called the amygdala. Unfortunately, the amygdala is one part of the brain that is directly effected by our thoughts. So you have an attack and then you worry about having an attack, which doesnt let everything get back to normal and before you know it you are in a cycle of them. However, if you acknowledge what is happening, that this part of the brain is acting exactly as it should when faced with threat, they do subside more easily. One of the best things you can do if you have one is to do some exercise, even though your heart is pounding and you feel weird.. it helps your brain feel like you are running away. Or you pound on something like a pillow with your fists.. that will make you feel like you are fighting back. In any case, they can be overcome with some patience, knowledge, and good humor.
References :

i've been suffering from panic attacks for almost a year now. for me, its the feeling that i cannot escape. everytime i have to speak in front of people, or sing at a gig with my band, i always make sure there is a back up plan. and that makes things easier. but i've had many embarassing public panic attacks so i know how you feel. its stress and embarassment, claustrophobia and fear. alexsplinter89@hotmail.com if you want to talk. good luck talking to your GP, he/she 'll only prescribe escapism medicine which won't hit your problem head on and will also cost a bomb.
References :

Anything and everything

Stress - Health - Anxiousness etc.
References :

No one really knows. The symptoms are caused by a flood of adrenaline into your system
References :

Stress.
References :