Hello and welcome to Healthcare Magic. Thanks for your query.
To answer your question directly, no panic attack
"physically kills" an individual. No anxiety
disorder, including panic attacks, requires a "defibrillator" to bring back the patient to life. The facts which you have mentioned that "her heart stops" and that she becomes "legally dead" are totally inconsistent with a panic attack.
However, you mention that she has had tests and has been told by the doctors to have "severe panic attacks". It is not possible for me to give you an exact diagnosis without a detailed history and a proper evaluation / psychological assessment of the patient. So, I would suggest that you discuss and clarify with her doctors regading her exact diagnosis.
Wish you all the best.
Dr. Jonas Sundarakumar