Louise Banks, 23, had an open-heart surgery to repair the 4cm hole in her heart that was not diagnosed for the last twenty-three years.
While at school, Louise Banks was branded a "fainty child" and her PE teacher called her lazy because she often collapsed during physical exercise.
Doctors wrongly diagnosed her condition in her earlier years as epilepsy. The hole that cardiologists said was the biggest they had seen could have killed her.
When she was 14 she complained of having palpitations up to 70 times a day. At 16, she was "fed up with taunts" and decided to join a gym to prove herself fit.
It was there she found that while running on the treadmill her heart rate went down instead of going up.
This January her condition was finally diagnosed after a new GP recorded an irregular heartbeat during a 24-hour monitoring test.
According to her doctor, "the scan revealed a tear 4cm (1½in) long in the partition between the right and left side of her heart that enlarged when more blood was being pumped through." This resulted in lack of oxygen in the blood reaching her brain, causing her to collapse.
Ms Banks said: "I always knew there was something wrong because I could feel my heart start and stop like a baby wriggling in my chest. I'm looking forward to my new life. It will be great to be able to dance with my friends without collapsing."
Louise Banks is now back after the surgery at her home in Exeter, Devon, with her partner Matthew Folland, 30, and their four-year-old son Ben.