The day Victoria Macarthur-Stanham nearly died started just like any other.
She woke up, went to work, returned home, had dinner with her fiancé and put her baby daughter to bed.
The then-29-year-old, who works in finance and lives in Coledale, NSW, was checking her emails at about 9pm when she collapsed.
Her now-husband Tim Prowse was drifting off to sleep upstairs when he thankfully heard the thud and went to investigate.
Victoria had suffered a sudden cardiac arrest and describes what happened next as "miraculous".
Realising this was different to the fainting spells Victoria had previously experienced, Mr Prowse called an ambulance and started doing CPR.
His voice falters and his eyes well with tears when he recalls that night, but in the moment he remained calm.
"It wasn't an emotional experience at that time, I was very pragmatic about what was happening, it was a serious time that called for a serious and measured response," Mr Prowse said.
With the guidance of an ambulance officer on speaker phone, Mr Prowse did CPR on Victoria on their living room floor for around 15 minutes until paramedics arrived.
"We're very lucky I've been a member of Palm Beach Surf Lifesaving Club for nearly 20 years now, so very lucky that I've had a substantial amount of CPR training," Mr Prowse said.
The significance of Tim's quick and effective CPR can't be overstated.
Sudden cardiac arrests happen when the electrical activity in the heart stops and the organ can't pump blood around the body, causing death within 10 minutes.
They can and do kill otherwise healthy young people, being one of the most common causes of death in Australians aged from one to 50 years old.
The Victor Chang Cardiac Research Institute says around 20,000 Australians suffer a cardiac arrest outside of hospital each year and 90 per cent of them die.
The few who survive can have cognitive or physical impairments.
Fifteen months on from that traumatic night in March, 2021, Victoria has had a second baby girl and is a picture of health.
She said her memory of the incident and the next four or five days in Wollongong Hospital are "pretty murky."
Victoria's mother Edwina Macarthur-Stanham didn't realise how precarious her daughter's condition was until she arrived at the hospital and was quickly ushered in to see Tim.
"The ambulance people came through and said: 'Your son-in-law is a miracle worker, he has done the most amazing job, you have no idea.'
"And I could see on their faces and Tim's face that this was a crisis," Mrs Macarthur-Stanham said.
With medical care she only has praise for, Victoria recovered and was determined to carry on with her upcoming wedding.
Just five weeks later the couple was married in an event Edwina described as a "joyful celebration and an affirmation of life and love".
Victoria said she married her hero.
"Tim isn't someone that would wear the badge of being a hero, he's very pragmatic and very humble, but he 100 per cent saved my life and I am completely indebted to him," she said.
"It's not a fortunate thing, it's a miraculous thing that I've come out through the other side of this as I was before."
The breakthrough screening test to reduce sudden deaths
Professor Jamie Vandenberg is a leading cardiac genetic researcher and co-deputy director at Sydney's Victor Chang Cardiac Research Institute.
He said sudden cardiac arrests in young people "send alarm bells" for the "high chance" that a genetic condition is to blame.
"In probably about a quarter of cases the genetics is the primary cause and that's when we've got to pull out all stops to find out," he said.
"Because while it may not have saved that person, we know that if it's a genetic basis that many other members of their family could also be at risk.
"The problem with these genetic mutations is that they're often silent, so the patients themselves don't know and it's only when the first member of the family has a major event that we then find out."
Existing tests to search for genetic clues can take months, or even years, to pinpoint a cause, but the Victor Chang team has developed a new electrical test to speed up the process and save lives.
"Rather than now looking at one mutation at a time, we can look at a hundred mutations at a time," Professor Vandenberg said.
"And in the particular syndrome that we're looking at, called Long QT syndrome, we can give clinicians greater confidence that they've identified the specific cause, so they can then screen the rest of the family to see who else is at risk."
Put simply, Long QT syndrome affects the behaviour of the electrical currents in the heart.
Mrs Macarthur-Stanham was diagnosed with the condition in the wake of her cardiac arrest and screening showed her mother Edwina and youngest daughter, four-month-old Indigo, also have it.
Both women have had pacemaker/defibrillators implanted in their chests "as an ultimate insurance policy" and all three now take medication.
"We're in the fortunate position to know the risks with Indi and to have the most brilliant medical minds in the world to collaborate with to understand how we can reduce her risks so she can live a normal and full life."
Professor Vandenberg now has his sights set on other gene mutations that can cause cardiac arrest as well as medical conditions that affect different parts of the body.
"This particular assay [laboratory test] we've developed is focused on those proteins that control the electrical signals in the heart," he said.
"But electrical signals are also important for the brain, our operation of muscles, kidneys, gastrointestinal system … almost every organ system in the body.
"In the long term we've got the opportunity to have characterised every possible variant in this ion channel gene and upload that to a publicly available database.
"Then in the future anybody who has their whole genome sequenced — and that is going to become much more common — can quickly make sure any variants they've found in their ion channel genes, whether they're a risky variant or whether it's a benign variant that they don't need to worry about."
Haris Haqqani is a cardiologist and electrophysiologist who treats patients with genetic heart conditions at Brisbane's Prince Charles Hospital.
He referred to sudden cardiac arrest as sudden death.
"Sudden death is different to heart attacks in that it disproportionately affects young people, children, adolescents and young adults and the impact of that both on the family and on society really can't be quantified, it's a devastating outcome," he said.
Dr Haqqani wasn't involved in the research and said it "will be game changing" and "may turn out to be revolutionary."
"They're going to be able to, as a result of Professor Vandenberg's work, redefine the criteria that we use to say that a disease-causing gene mutation is actually significant, verses a benign background problem," he said.
Dr Haggani said in the future the "holy grail of genomics" will be the capacity for individuals to have their whole genomes read.
"But that could only work if we have a way of sorting out the signal from the noise, much in the way that Professor Vandenberg's work has helped us," he said.
"Right now, if we did that [whole genome sequencing] we would be finding a whole bunch of benign variants that are never going to cause a problem."
'You'll never regret knowing it': A plea for others to learn CPR
While not everyone who suffers a sudden cardiac arrest has an underlying genetic condition that could be treated if detected, many would have a better prognosis if they received prompt CPR and defibrillation.
Victoria Macarthur-Stanham said she feels like she has been given a second chance at life.
"Everything pre-cardiac arrest was a bit of a dress rehearsal and now I'm constantly pulled back to the power of the present."
She said she has a "fire in her belly" to raise awareness about defibrillators and CPR.
"I am incredibly fortunate to marry someone who had those skills and had I not had that fortune it would have been a completely different story and one that you don't even want to think about.
Tim Prowse said when faced with the potential death of a loved one "you'll never regret knowing what to do."
"Even just basic life support is something that's really important," he said.
"It's hard enough when you're in public and you come across an emergency with a complete stranger, you want to know what to do if it's a family member."
The sentiments are echoed by the medical experts.
"If someone has had a sudden cardiac arrest time is absolutely critical, for every minute that we take before we defibrillate somebody, about 10 per cent of people will die," Professor Vandenberg said.
"So you've got to get in there, use the defibrillator, use your CPR, get your training done for CPR and encourage all your family, all your friends to get CPR training as well."
Dr Haqqani said the countries that have reduced deaths from sudden cardiac arrests have done so through public health measures and awareness.
"There are AEDs [automated external defibrillators] on every street corner, every lay person is a potential rescuer and no one is afraid of CPR," he said.
