Investigators said they made the determination after learning that Charles Keith Teer, 49, had heart problems long before the confrontation with William Russell Redfern, an artist who has won recognition for drawings he does with his feet.
"The autopsy revealed he had serious heart disease and blockages and they'd been there for quite awhile," Snellville Police Chief Roy Whitehead said.
He added, however, that misdemeanor charges such as criminal trespass or simple battery against the 44-year-old Redfern were still a possibility.
Teer and Redfern scuffled Monday in the driveway of a suburban Atlanta home.
Redfern, who was born with no right arm and a stump below his left shoulder, kicked Teer, and Teer hit Redfern during the fight, authorities said. Teer complained of feeling dizzy after the fight, collapsed, and died.
The fight stemmed from bad blood over a woman who once dated Teer and now dates Redfern, authorities said.
A woman who answered the phone Tuesday at Redfern's home in suburban Tucker said he had no comment. She declined to identify herself.
Known by the nickname "Rusty," Redfern made a name for himself in the late 1980s for pen and ink drawings he does using his foot.
According to the Web site for VSA Arts - an affiliate of the John F. Kennedy Center for the Performing Arts that promotes and showcases artists with disabilities - Redfern's drawings take one to six months to complete.
He was one of six Georgians who represented the state at the 1989 International Arts Festival in Washington, and was commissioned by Georgia's then-Secretary of State Max Cleland for a series of illustrations depicting the state capitol.
According to the site, he started Redfern Originals Inc. in 1987, producing Christmas cards, stationery and limited-edition prints.