Not just hold the belief but eat that way even more consistently (more butter and less sour cream just because tastes change, but same basic principles). I'm young and didn't have any obvious signs of heart disease personally so can't say it "worked out" for me personally in that literal, narrow sense but I feel better, more mentally clear, etc. (I know that's kinda whatever of evidence, just saying since you asked).

Someone else recently posted their success with butter lowering their measurement of arterial plaque: "the second score was better (lower) than the first score. The woman in charge of the testing center said this was very rare — about 1 time in 100. The usual annual increase is about 20 percent." (http://blog.sethroberts.net/2011/08/04/how-rare-my-heart-scan-improvement/) (Note: I disagree with the poster's reasoning methods in general, just noting his score change.)

There was a recent health symposium that discussed this idea and related ones: http://vimeo.com/ancestralhealthsymposium/videos/page:1/sort:newest.

For those specifically related to heart health, these are most of them: http://vimeo.com/ancestralhealthsymposium/videos/search:heart/sort:newest