The collective wisdom here is that, to lower the risk for a heart attack, one would eat less of everything: fat, carbohydrate, and protein. Perhaps it doesn't matter what the macronutrient make-up of your diet is as long as you're eating less of it.
There was a slight advantage for reducing carbs. It's hard to say if this was significant in this informal poll. But if it's true, that would mean, by default, eating more fat and protein. (The converse is also true ... If you were cutting back on fat and animal protein, the bulk of your diet would be carbs.)