What Causes Chest Pain , Headache , Dizziness And Numbness In The Legs?

symptoms are chest pain, headache, dizziness, and numbness in legs. It s not me...but a friend. She is in early 70 s, had a CABG about 20 years ago. They just released her from hospital and couldn t find anything wrong except 2 small hernia s in abd region. I was hoping to find more information . I am an RN. I believe it is cardiac, but they did CT, echo, ekg and stress test...all came back fine. Thank you. rnntt2@g