A coroner has confirmed a Cape Breton teen who died while running in the Toronto Marathon had an undetected heart abnormality.

“She did have an anatomical abnormality in her heart that was there probably from, or definitely from birth, that caused her heart to stop suddenly and caused her to collapse,” says her father, Steven Van Nostrand.

Emma van Nostrand collapsed on Lake Shore Boulevard near the end of the 42-kilometre race on Sunday.

Police say the 18-year-old Coxheath, N.S. woman was found without vital signs. Attempts were made to revive her, but she was pronounced dead after bring rushed to hospital.

“I don’t even know what the statistics are of how often these happen but unfortunately for us, our daughter had this and, in doing what she chose to do, given her personality, wanting to be challenged,” says Steven.

The van Nostrands don’t believe the marathon took their daughter’s life, saying she likely would have died from overexertion at some point.

“It gives us some sort of satisfaction knowing that there’s nothing we could have done ahead of time to have prevented it and that Emma, you know, had something that she couldn’t have stopped,” says Steve. “Had she known, would she have stopped, given her personality? I doubt it.”

The news of van Nostrand’s death has devastated students at Riverview High School, where the teen was a Grade 12 honours student.

Principal Joe Chisholm says van Nostrand was a model student, was known for her academic and athletic involvement in the school, and was well liked by both students and staff.

“She played soccer for us. She played basketball for us. She was an honours student,” says Chisholm. “This school term, to improve her French, she actually took it upon herself to go to France and take a couple of months in France.”

The race was the teen’s first full marathon after running three half marathons in the past 18 months.

Emergency room physician Dr. Chris Milburn, who is also a runner and a friend of the van Nostrands, says this kind of tragedy is rare and shouldn’t discourage people from running.

“This kind of event, that we call sudden cardiac death in athletes, can occur during any kind of athletic competition,” says Milburn. “So, it’s nothing to do specifically with the stress of the marathon.”

A Mother’s Day run is planned for the weekend to honour van Nostrand’s memory.

Her body will be brought home on Wednesday. Funeral arrangements are pending.

With files from CTV Atlantic's Ryan MacDonald