Dr. Rob Kurtzman, the Colorado forensic pathologist who performed the autopsy, said the three arteries were 90 percent clogged, and noted Lay had suffered two previous heart attacks, and had coronary artery stents in place to increase blood flow when he died July 5 in his rented Aspen, Colo., home.
Kurtzman said while Lay had been taking medication for upper gastrointestinal symptoms, there was "no significant toxicology that contributed to his death," the Houston Chronicle reported.
Prior to his collapse, Lay did not complain of any chest pains to his wife, the pathologist's report said.
Lay and former Enron Chief Executive Officer Jeff Skilling were convicted May 25 of federal conspiracy and fraud charges for lying to investors about the company's finances before its 2001 bankruptcy. Lay was also found guilty of four counts of bank fraud and was to be sentenced in October.