I had a panic attack which caused me to not be able to inhale and I was trying to catch my breath and calm myself down; I thought I was dying and would dive into the carpet before reaching my cell phone; I think these attacks can also be spiritual, as I've never had one before and an immediate one month trial on a heart holter monitor did not reveal any heart problems. Drs. don't know the cause, even a psychiatrist; I think I know what it was but is too controversial, even, to post. 'certainly do hope it never happens again because it was very terrifying to think you are dying and can't help it.