FYI...

"Heuristic technologies can be found in nearly all current anti-virus (herein referred to as AV) solutions and also in other security-related areas like intrusion detection systems and attack analysis systems with correlating components. This article will offer a brief overview of generic heuristic approaches within AV solutions with a particular emphasis on heuristics for Visual Basic for Applications-based malware...."

http://www.securityfocus.com/infocus/1542