Choi was rushed to Gangnam Severance Hospital for CPR at 2:46 p.m. but was pronounced dead on arrival.
Membership is free, but to be an IPDFA member studio, instructors have to be First Aid and CPR-certified.
He received a medal from the National Safety Council in 1931 after using prone pressure resuscitation to revive two truck drivers who had been overcome by carbon monoxide in the Union Stock Yards.
He was attended by doctors of both teams, who revived him with cardiac massage and the use of a defibrillator; he left the stadium in a stable condition, subsequently undergoing tests at the Salamanca University Hospital.
Both were in evidence when he poleaxed New Zealander Ewen Chatfield, whose life was saved by mouth-to-mouth resuscitation and heart massage at Eden Park, Auckland.
Umpire Max O'Connell then provided mouth-to-mouth resuscitation, and Darling was taken off the field.