One minute Melissa Dorans was happily chatting to her three girls in the back seat of the car; the next she felt like "an elephant" had sat on her chest.
But while the heart attack was swift, the diagnosis was not immediate and the cause remains unclear.
That's partly because the healthy, fit young Shellharbour mum wasn't a 'typical' candidate for a heart attack, and partly because the type of heart attack she experienced is fairly uncommon.
The 30-year-old had a spontaneous coronary artery dissection, or SCAD, exactly one week after delivering her third child last October.
Unlike a typical heart attack caused by a clot that blocks an artery, a SCAD heart attack starts with a tear in the wall of an artery. The tear blocks the blood flow to the heart, causing a heart attack, abnormalities in heart rhythm or sudden death.
The average age of SCAD sufferers is just 42, 80 per cent of sufferers are women and it typically occurs in healthy, often fit adults with no standard risk factors for heart disease.
"We were driving back from my mother-in-laws and I turned around to talk to the girls, and when I turned back I felt this crippling chest pain - like an elephant had sat on my chest - and shortness of breath," Mrs Dorans said.
"My husband was driving and I told him to drive straight to Shellharbour Hospital, where a few tests were done. But while troponin - the enzyme that's elevated in the blood after a heart attack - was present it was only at low levels.
"Within hours though the levels had gone from 25 to 400 and I was sent to Wollongong Hospital's coronary department for more tests. An angiogram eventually found two dissections."
A stent was inserted in one, the other was left to repair itself - and six months on, after some rehabilitation and with ongoing medication, Mrs Dorans is getting back to normal.
However she "hates" that she has the condition, and she's desperate to ensure that more research is conducted into it, and that other women are aware of it.
For although SCAD causes a small percentage of heart attacks overall, It's the number one cause of a heart attack in women under the age of 50. It's also the number one cause of heart attack in pregnant women and new mothers.
That's why Mrs Dorans hopes other young heart attack survivors and community members will join her at the first Wollongong SCADaddle for SCAD Research in Stuart Park on May 5.
SCADaddle events have been held around the country by other young survivors, and head of the SCAD Research program at Mayo Clinic Professor Sharonne Hayes said: "Patient advocacy has been and continues to be a critical component of our success. We need everyone involved to educate, advocate, raise awareness and research funds."
For details of the Wollongong, and other events, visit www.scadresearch.com.au