Left-back McHattie was sent off for a professional foul on Calvin Zola in the incident which led to Aberdeen's penalty and equaliser in their eventual 2-1 defeat.
An appeal was lodged with the Scottish Football Association, but a disciplinary tribunal upheld the original decision and McHattie will now serve a one-match suspension.
That rules him out of Saturday's trip to Inverness along with captain Danny Wilson, who was sent off after the final whistle against Aberdeen for using offensive language.
Hearts boss Gary Locke told the club website: "I'm very disappointed at the outcome. We have to take it on the chin and move on.
"At least I know who is out for the weekend - Kevin and Danny Wilson are now suspended. I'll have to look at things in terms of shaping a team."