The Los Angeles County coroner's office has ruled that conservative blogger and commentator Andrew Breitbart died of heart failure stemming from coronary disease. A coroner spokesman said that a negligible amount of alcohol was found in Breitbart's system but no prescription or illicit drugs. Foul play is not suspected, and the case has been closed. Breitbart, 43, died March 2 at Ronald Reagan UCLA Medical Center after collapsing as he was walking his dog near his Brentwood home. (More Andrew Breitbart stories.)