Patricia Baas

It was February 1996 when Patricia Baas of Melbourne started to feel what she calls discomfort in her upper back. "It felt like if you could stretch or move around, it would go away, like a muscle was out of whack," she says.

As the day went on, she started having difficulty breathing, like her throat was closing up.

She tried to call her sister, a nurse, but couldn't reach her. Finally, Baas, a lawyer, asked a co-worker to call 911.

She got to the hospital and was waiting with another, older woman when she heard a nurse telling someone that a patient suffering a heart attack had just come in.

"I thought, 'Oh, they're going to take care of the heart attack and then they'll come take care of me,' " Baas says.

When the staff came to take her up to the cardiac catheter lab, Baas realized she might be the heart attack.

She underwent an angioplasty, and when she woke up, doctors told her she'd suffered a heart attack, and one of the arteries in her heart had been 98 percent blocked.

Even though both her parents died of heart disease - her mother at 41 and her father at 54 - it had never occurred to Baas that she should be worried.

And, like many women, she didn't suffer the tell-tale symptoms so many people are told to look for.

"The pain was in my back. I always thought that I'd have this huge pain in my chest or pain in the left arm," says Baas, now 46.

"Nobody would have suspected a heart attack, given my age and whatever," Baas says. "From that day forward, every day's been a gift."