Guinea Pigs Sudden Death

Question
Today my guinea pig Winnie had died suddenly. She was fine this morning and in the afternoon she was acting weird. I took her out of her cage and placed her on my bed. She lied down with her neck turned in a different direction. She felt floppy, then i knew something was wrong. She was breathing fine. Then i watched her carefully until a half hour later she began to breathe heavily, then trying to get some air. She suddenly stopped breathing and started to breathe again. After a few minutes I knew it will be all over for her. She stopped breathing, and that was it. I was devestated.
I don't know what went wrong. She was a very young guinea pig.  Is there anyway you would know how she died?  

Answer
Amanda,

I am sorry about Winnie's death. I am sure she had a good life with you and that you cared about her very much. Always remember the good times you had with her.
It sounds like Winnie may have had a heart attack. A lot of Guinea Pigs have a weak heart and over time it just stops functioning or the heart has a heart attack. Just by the description giving and the fact that she was fine earlier in the day I would say a heart attack or her heart just failed are either the likely cause of her death.

I hope this helps,
  Take care,
    Jules