Whatever you go in for, just make sure you complain about chest pain. That should buy you at least a 24 hour observation reprieve. After you finish your second night you can claim a miraculous recovery.
You can be in the hospital for 5 days, and still be considered observation under Obama criteria. The best way to do this is to have someone who has access to the guidelines publish them on the internet. You can then determine what your “symptoms” should be.