There were no warning signs when teenager Austin Blight went into cardiac arrest.
The 17-year-old collapsed unconscious at the gym, where staff rushed to his aid and quickly realised he didn't have a pulse.
He survived because staff performed CPR and used an automated external defibrillator to shock his heart before paramedics arrived.
Since his medical condition in 2024, Austin has returned to school to finish year 12 and is back working out in the gym.
He lives in Victoria, where residents are more likely to survive a heart episode than any other Australian state and almost any other place in the world.
Groundbreaking advances in response and survival rates across the state have been revealed in the Victorian Ambulance Cardiac Arrest Registry annual report for 2023/24.
It found Victoria has the best cardiac survival rate in the nation, and the third-best in the world behind King County in the US and Denmark.
This is all thanks to early intervention, with bystander CPR administered in 79 per cent of witnessed cases and 141 cases receiving a shock from a public automated external defibrillator (AED) - the highest number on record.
As a result of these interventions, and the work of paramedics and first responders, 422 cardiac arrest patients were discharged from hospital, with 84 per cent returning home to their families.
Victoria has more than 7500 publicly accessible defibrillators, significantly improving the survival rates for cardiac arrest patients, who without CPR or defibrillator intervention have only a 5-10 per cent chance of survival.
Ambulance Victoria's free GoodSAM app, which alerts people to someone in cardiac arrest nearby, is also making a difference with 17,327 registered responders and 793 cases attended by volunteers in the last year.
Integrated with the triple-zero emergency service, the app connects patients with registered volunteers who can provide CPR and defibrillation until an ambulance arrives.
Ambulance Victoria's director of research and evaluation Ziad Nehme praised the collective effort that led Victoria to its highest internationally comparable rate of 41 per cent of patients surviving to hospital discharge.
The rise from 36 per cent in 2022/23 marks the largest annual increase in the past decade.
"These improvements in survival are not by chance," Dr Nehme said. "When CPR and defibrillation are provided quickly, survival chances increase significantly."
Ambulance Services Minister Mary-Anne Thomas said it was impressive to see Victorians going out of their way to help others in need.
"Minutes matter in cardiac arrests and when a patient receives CPR and defibrillation before paramedics arrive, their chance of survival increases significantly," she said on Monday.
