Burgerheart is a colloquialism used to describe either a heart attack of American proportions, or a heart and arterial system so clogged with cholesterol that a heart attack is imminent.
"Did you hear about Bob?"
"No, what happened?"
"He died of Burgerheart."
"Aww man that sucks, he shouldn't have had so much McDonalds. RIP."
To maximize one's potential gain at the expense of others. To rip someone off while at the same time leading them to believe they are getting a good deal.