The report blames severe coronary artery disease for Lay's death. It also said the autopsy showed Lay had suffered at least two previous heart attacks and had two stents implanted to clear blockages. The report does not specify when the heart attacks occurred.
The Lays were vacationing near Aspen, Colo., when he died. The report, prepared by the coroner in Mesa County, Colo., said Lay was last seen alive by his wife on July 5 at 1 a.m., when he woke up and went into a bathroom.
Minutes later, she heard a "thump," and found him on the floor, the report said. He had vomited and showed signs of having a seizure. Linda Lay called paramedics, but Lay was pronounced dead on arrival at Aspen Valley Hospital.
Lay, 64, and former Enron chief executive Jeffrey Skilling were convicted May 25 of fraud and conspiracy for lying to investors and the public about the financial health of Enron before the energy company he founded collapsed in 2001.
He also was convicted of one count of bank fraud and three counts of lying to banks in a separate, non-jury trial before U.S. Judge Sim Lake stemming from his personal banking. Lay died insisting he'd committed no crimes, and planned to appeal.
Lay showed no signs of either physical or mental weakness before or during his trial, reported CBS News correspondent Barry Bagnato. He was combative on the witness stand and was hurt by his main lawyer's sudden illness.
Skilling, who now faces sentencing alone on Oct. 23, also aims to appeal and faces decades in prison.
After his conviction, Lay faced the prospect of the rest of his life in prison. His death sparked myriadon the Internet, some tongue-in-cheek, others questioning whether he faked his demise.
Former President George H.W. Bush and his wife, Barbara, were among the mourners at Lay's funeral. The funeral drew some of the high-profile guests who were close to him before he was convicted.