My friend just had a spell at work and we are wondering what could have caused it. He got burning hot from his upper chest to the top of his head. He got pale and sweat was dripping off of him. In a few minutes he was OK. He checked his blood sugar. It was up just a little. What could have caused this? He had a stent put in several months ago but doesn't think it is anything to do with his heart. He takes about 8 medications for diabetes and his heart. He just had a checkup with heart doctor last week and all was OK.

What could it be?