I've Had A Mitrol Valve Replaced In 2008 About 3

I've had a mitrol valve replaced in 2008 about 3 yrs ago I started have these episodes they would occur once about every five weeks lasting about 24 hrs. Usually about 12-14 times in that day I would suddenly get real hot feel nauseous and turn real pail and about pass out. They last about 4-5 minutes then I'd be fine for another hour Or so the. It would happen again. The day after i feel fine except I'm tired from the stress from the day before.