It was while learning to save the lives of others that Robyn Shore almost lost her own.

The Hamilton teacher dropped dead for seven minutes while completing a St John course with a class full of her workmates in Hamilton.

Had it not been for the know-how and quick actions of her tutor Christina Saunderson, the grandmother firmly believes she would not be alive today.

MARK TAYLOR FAIRFAX NZ Survivor Robyn Shore thanks First Aid tutors Christina Saunderson and Craig Williams for saving her life.

"She is my hero, she never gave up on me," said Shore in a teary reunion at St John Seddon St offices.

"I am so lucky, I live alone so it could have happened at any time. The doctors told me I was the luckiest woman alive at the time."

Shore had signed up for the course through her work at Koromatua School in rural Temple View.

Always a character and a bit of an actor, she was animated through the first hours of the morning course on January 26 this year.

"I actually thought she was acting, she was injecting her personality into it," Saunderson said.

"Except you weren't acting and when you collapsed I realised the way you looked and how you presented it was serious.

"It was the first time we've had anyone collapse and it was all very surreal."

The next thing Shore remembers is Saunderson's face, glowing from above.

"I remember coming and acting a bit of a fool. The next thing I was waking up to these people in green on top of me."

Shore had gone into a mild seizure. Her face turned, her eyes wept and she stopped breathing.

"Initially I wasn't sure what it was, so we cleared the room and started CPR," said Saunderson."

Saunderson screamed for an ambulance and defibrillator which rapidly arrived in the hands of neighbouring tutor Craig Williams.

"We shocked her one time, continued CPR for another minute and shocked her again."

After seven minutes Shore opened her eyes and apologised.

"The first thing she said was 'I'm sorry, I will get up now'," Saunderson said.

But she couldn't.

"I felt all right in myself, my brain felt fine, but then I couldn't get up, I couldn't use my arms or legs."

Shore was rushed to Waikato Hospital where she spent 10 days recovering from a sudden cardiac arrest.

Doctors told her the electrics in her heart had gone "haywire", causing an "atrial fibrillation" - a rapid, irregular heart beat sending the heart into arrest.

​Cardiac arrest was a shock for Shore, who has no family history or pre-existing heart problems. She admits to bouts of flu over the last three winters and the odd anxiety episode, but has never experienced any heart palpitations.

"I had noticed I wasn't the same person I was a few years ago, whether that was part of it I don't know?

"I was very tired at the time. I had been doing a lot of gardening, was getting the classroom ready and I had been feeling a bit hot."

Tests revealed nothing sinister, so doctors put her on medication. She has also been fitted with an internal defibrillator that keeps her heart on track.

Now it's a matter of "getting well", she says.

"When I told the doctor my skin peeled off due to the medication, he said 'well you were dead'. You just do what you can."

Giving immediate CPR and knowing where to find a defibrillator could easily save a life, said Williams.

"Remarkably what happened to Robyn that day is exactly what we train for on courses, and it could happen anywhere to anyone."

"It's not complex, just stick to the basics."

When someone is dead, doing something was better than nothing, Williams said.

"You are not making the person any worse, pump hard and pump fast on their chest."

Since the incident, Shore has returned to complete the first aid course she now recommends to everyone.

"It could happen to anybody we know."

The school is also raising $3000 to purchase a defibrillator.