Hugh Hefner died of cardiac arrest, E. coli infection

Hugh Hefner
In this Nov. 15, 2007 photo, Hugh Hefner smiles while signing copies of the Playboy calendar and Playboy Cover To Cover: The 50's DVD box set in Los Angeles. Playboy will no longer publish photos of nude women as part of a redesign of the decades-old magazine, according to a news report Monday, Oct. 12, 2015. Executives for the magazine company told The New York Times that the change will take place in March 2016. Playboy editor Cory Jones contacted founder and current editor in chief Hugh Hefner recently about dropping nude photos from the print edition and he agreed, the Times reported. (Ian West/PA via AP) UNITED KINGDOM OUT NO SALES NO ARCHIVE

(ENTERTAINMENT TONIGHT)  After the private funeral of Hugh Hefner on Saturday, new details have emerged about the death of 91-year-old Playboy founder.

ET has obtained a copy of Hefner’s death certificate from the Los Angeles Department of Public Health, which lists the immediate cause of death as cardiac arrest.

Secondary causes include respiratory failure, septicemia and drug resistant E. Coli. The E. Coli is listed as being from an “undetermined etiology,” meaning the origin of the highly dangerous bacteria could not be confirmed.

Hefner died on Sept. 27 at 5:06 p.m., according to the certificate, and his occupation was listed simply as “Playboy Founder.”

A source close to Hefner’s family told ET after his death, “Hef hadn’t been doing well for the last year. [His death] wasn’t shocking to the family.”

“Everyone is obviously sad, but they feel he lived a very fulfilling and long life,” the source added.