During my final year project for my BSc, I tried to address the problem of losing the temporal data from eye tracking in heatmaps with an accelerated replay, heatmap animation. Here's an example:
Definitely a step up from heatmaps, though I think there's a lot to be said for providing data as a static image rather than a heatmap, especially when they are being added to a powerpoint or PDF.
http://www.youtube.com/watch?v=L319pLmzHVc&feature=chann...
This video shows a selection of sittings from radiologists reporting on chest xrays.
If I recall correctly it is sped up approximately 5 x realtime.