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Three-time Olympian Vicki Roycroft is in ICU at Sydney's RPA after a suspected heart attack.
The 69-year-old equestrian is understood to have collapsed just before she was due to compete in the show jumping at the Sydney Royal Easter Show on Saturday afternoon.
Roycroft's sister Joanne gave family and friends an update, according to a Facebook post, saying Vicki has a large tear in her aorta and was undergoing and eight-hour surgery.
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The 69-year-old was not breathing for approximately 10-minutes during the medical episode, Joanne said, estimating doctors won't know the full extent of damage caused for another three to four days.
The family say the doctors have been amazed by the Olympian's fitness but the family are asking people to pray for her recovery.
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A spokesperson for the Sydney Royal Easter Show confirmed the incident, which resulted in Roycroft being taken to Concord Hospital before she was transferred to RPA.
"The on-site St John Ambulance team attended to her immediately, with treatment also provided by NSW Ambulance paramedics," a spokeswoman told the Sydney Morning Herald.
"The thoughts of the entire Royal Agricultural Society of NSW and horse community at the show are with Vicki and her loved ones at this time."
The Sydney-born Australian equestrian competed in three Olympic Games – Los Angeles in 1984, Seoul in 1988 and most recently Atlanta in 1996.
Roycroft was among the first to receive the Australian Sports Medal, in 2000, awarded by the Governor-General in recognition of Australian sporting achievements.
The equestrian was married to fellow three-time Olympian Wayne Roycroft for 24 years, with the pair marrying in 1976 before separating in 2000.
Their son, Mark, tragically died in January 2003 after he got caught in a rip off Birdie Beach on the NSW Central Coast, at the age of 17.
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