Comedian George Carlin died yesterday of heart failure at a Santa Monica hospital. He complained of chest pains and was admitted in the afternoon and he died at 5:55 p.m. He was 71. According to the "Review Journal", Carlin who had a history of heart trouble, performed as recently as last weekend at The Orleans. Carlin owned a condominium in Las Vegas and was part of the headliner rotation at The Orleans. He also performed there in April and was scheduled to return in August.