Can you mount a flat screen HD TV above a gas fireplace?

I of course realize that you can but should that be done or would there be too much heat rising off the fireplace?
The house is under construction.
The plan is to use the (LP) gas fireplace only for emergency heat when there is a power failure. This would be a ventless type fireplace and would not be overly large. The TV would be in the neighborhood of a 40 to 52 inch widescreen. The wall is 2x6 exterior wall 16 inches on center.