Damn that's really fu*ked up to hear that. And he seemed like he was in good shape atleast it other things going on internal that we don't see on the outside. But I guess it can happen to anybody no matter how in shape you are. Damn R.I.P. MCD
He was huge. He probably was using growth hormone and steroids and supplements and working hard in the gym. Those things can lead to heart attacks. Look at wrestling. It's incredibly, incredibly hard to get as big as he was without roids unless you're working out for like 6 hours a day.