When it comes to matters of the heart, it's always best to take great care.
A specialist team at Waikato DHB is doing just that, developing a world-class simulation training programme to prepare for when things go wrong in the operating theatre.
In cardiac catheterisation laboratories, known as cath labs, they carry out some complex, high-risk procedures on the heart - things like putting in stents and pacemakers.
Waikato Hospital interventional cardiologist Dr Madhav Menon says most of the time it runs like clockwork, but on rare occasions things can go wrong.
"We can perforate a vessel, we can perforate an artery, we can bleed around the heart, the heart valve can rupture, your pacing wire can cause holes," Dr Menon says.
"It doesn't happen often, but when it happens it is a disaster."
Dr Menon helped develop a training programme to prevent chaos in a crisis.
"When a team panics, you get poor outcomes. There's no need to panic," he says.
"We practice a crisis, we practice the communication, and they have to go hand-in-hand for a good outcome."
The system, called REACT, was originally from the UK. It's been modified to meet with New Zealand requirements and uses real-world scenarios to put staff under pressure in a safe environment.
"It provides a calm team when things are going wrong. If you walked past my lab where we're standing now and something untoward was happening, with REACT, you wouldn't even be aware," says senior nurse Maree Smith.
Keeping calm is essential, because the patients are usually awake during the procedure and aware of what's happening.
"You know you're assigned to that and that's what you stick to and it flows, it's safe and yeah, it's very structured so it works," says registered nurse Annie Knight.
And it's already paying off. A recent patient's life depended on it, a cath lab procedure was his only hope, so the team set to work.
"He could have died on our table. We knew that. Patient knew that. Family knew that," says Dr Madhav.
"There was absolute silence in the theatre. We had a plan, we executed the plan, patient came out alive."
Dr Menon hopes to roll out the training to the rest of New Zealand and develop it around the world.