Thanks for your response. The damage occurred July-Sept., 2012 and previously July-Sept., 2011. I'd like to prevent it from happening again in the 2013 growing season, if possible. We have had drought conditions the past two years, which may be significant...bugs, beetles?
No, I don't have pictures but am learning to appreciate their value in cases like this.
Not sure what is causing the damage, but it sounds like caterpillars or the like to me. Heuchera don't have a lot of problems with predators. When I was doing a search, the black vine weevil kept coming up and although they make little half moon shaped cuts in the leaves, their primary source of damage is to the root systems.