SINGAPORE — It has only been three years since she started training with Wong Liang Ming, one of the Republic’s most illustrious taekwondo exponents, but Chelsea Ann Sim already has a trophy cabinet full of accolades, including an ASEAN Championship title, gold medals from regional meets, and a SEA Games silver medal.

What is most impressive about it all, however, is the fact that Sim has a hole in her heart. Literally.

Born with a congenital heart disease, the 19-year-old knows she is at risk of suffering a heart attack should her activities get too strenuous. Yet, she has somehow defied the odds to become Singapore’s best hope at a gold medal in taekwondo at this year’s SEA Games on home soil.

Sim attended her first taekwondo class at Aljunied Community Centre when she was 11, and she eventually found herself at Wong’s training centre at Lorong Limau in 2009 when she felt she needed a bigger challenge. From the moment Sim entered the premises, Wong revealed she knew Sim was something special.

“I think her condition makes her more determined,” said Wong, a four-time SEA Games gold medallist. “She was born natural. Although she came in quite raw like an unpolished diamond, it was easy for her to pick up and correct her mistakes.”

Though Sim competes in the poomsae segment, a non-contact form of taekwondo, her training routines are no easier than those of her counterparts. But instead of a toll on her health, Sim credits her punishing routines — she is currently training six times a week for the Games — for having helped build her physical strength and boost her immunity.

Determined to succeed in her goal to win her first SEA Games gold medal, Sim has to perform a delicate balancing act of pushing herself to the limits while knowing when to stop for a breather.

“Usually when we do physical exercises, I won’t use (my condition) as an excuse to sit out unless I feel very breathless and cannot continue. I know my own limits. I will sit aside and join the training again when I feel better.

“I guess once you have a heart condition, there is always the risk of having a cardiac arrest. I just have to monitor myself and take extra precaution,” she said.

But it seems her condition has not been getting in her way of achieving success. Sim has been in fine form: She won two gold medals at last year’s Asian Cities Gold Cup Taekwondo Championships in Hong Kong and another gold at this year’s 2015 US Open in Orlando, Florida. Sim is considered the only gold medal prospect in the eight-strong team that will be fielded at the SEA Games, though she is tipped to bring home another medal in the mixed pair poomsae which she will be taking part in with team-mate Kang Rui Jie.

Sim, who was also named the Meridian Junior College Sportswoman of the Year in 2014, was pipped to a gold medal at the 2013 SEA Games in Myanmar in what was a controversial decision that left many baffled. Having put in a near-flawless performance in the poomsae category, Sim took home the silver even though the host nation’s Yamin K Khine was clearly less adept in her routine. But she can count on it that history will not repeat itself.

Following the incident at the Myanmar Games, the ASEAN Federation had decided to do away with neutral referees. Only referees from South-east Asia will be allowed to judge this time round, and referees will not be allowed to judge athletes from their home countries.

Though Sim admits she was disappointed with the decision, she has quickly refocused herself to the task at hand. “I was disappointed but I learnt that there is no point in being angry. I cannot be affected on what I cannot control; judges may have their personal preference so that is when I change the way I perform to impress them. My goal for this SEA Games is to go for gold,” she said.