Vasovagal episode

I'd like to share with you my mother-in-law's story.
On Tues evening, I heard some "哼叫声“, I found my mother-in-law was on the toilet in the bathroom and she seemed not be able to breath smoothly with paled face. I asked her what's happened, she told me she could not stand up. She lost her energy and 没有劲。She had chest pain too. I called 911 and my mother-in-law was sent to emergency room at Lahey clinic immediately.

The 救护 officers who drove her to the hospital, measured her blood pressure, it was only 77. I remembered in June 2009 when she was sent to emergency room, her blood pressure was only 55. The doctor told me if the blood pressure was not raised up, she would pass away in 24 hours. By reading up  to here, do you guess if she had heart attack or stroke? That's what I thought even if I knew she just did the physical exam and
her chelestro was only 201.
The 救护 officers from Lexington were so professional (we are so lucky to live in Lexington!), after they gave her an aspirin and drank some water, she was recovered immediately --- even before arrived at the hospital!

The doctor told me this is Vasovagal episode:
http://en.wikipedia.org/wiki/Vasovagal_response
"A vasovagal episode or vasovagal response or vasovagal attack[1] (also called neurocardiogenic syncope) is a malaise mediated by the vagus nerve. When it leads to syncope or "fainting", it is called a vasovagal syncope, which is the most common type of fainting." For my mother-in-law, the reason could be "dehydration". She was watched overnight, and we went home the following afternoon.

Next time when this happens again, first drink a couple of water with a little bit salt! To prevent this happen, drink 8 * 8 oz water everyday.