When a 43-year-old man dies of an apparent heart attack, you look for something extraordinary that might explain it. In Andrew Breitbart's case, you don't have to look far.

One of the personality traits correlated with heart trouble is hostility. Redford B. Williams, who did the pioneering work on this several decades ago, found that men with a hostile disposition are more likely to develop irregular heartbeats and die before they reach 50.

I didn't know Andrew Breitbart, but, judging by his work, hostility was no stranger to him. David Frum wrote in an acute post-mortem appraisal, "He delighted in the enraged outburst, the shouted insult, the videotaped jab of a finger into an opponent's chest." Frum explains Breitbart's "intense focus" on President Obama this way: "only by hating a particular political man could Breitbart bring any order to his fundamentally apolitical emotions."

We can put a finer point on this. Williams used as his gauge for hostility the Minnesota Multiphasic Personality Interview--specifically, a subset of 50 questions known as the "hostility subscale". And as Williams has pointed out, some of these questions capture a part of a person's makeup that goes beyond hostility in the broad sense; they measure a kind of cynicism--"a contemptuous distrust of human nature and motives," as Williams put it.

In other words, these questions measure the kind of inclination that could lead you to see pervasive and calculated media bias. Dave Weigel recently recalled a phone conversation with Breitbart during the Journolist controversy. He remembered Breitbart saying, "The collusion. All of these reporters agreeing on how to cover a story so it didn't hurt Obama. It's disgusting. It's the corruption of the media. It's corrupt. This is corrupt. This is corruption." Too much of that could be bad for a person's heart.