Mr Low Guan Hock (right) found out he had a potentially fatal heart condition through the most tragic way - the death of his daughter.

Miss Lyn Low, 22, suddenly collapsed and died during an evening jog in a park opposite the family's Jelapang Road flat, five years ago.

The autopsy revealed she had hypertrophic cardiomyopathy, a genetic condition that makes the heart muscle abnormally thick and increases the risk of sudden death.

Doctors screened Mr Low, his wife, Lyn's elder sister and her younger brother for the condition, and found that Mr Low had it.

His daughter's death probably saved his life though signs had surfaced that he was not well about two years before she died.

The 53-year-old operations supervisor was having a shower one day when he felt suddenly breathless and dizzy.

He said in Mandarin: 'I raised my head and gasped for air, but I couldn't seem to suck in any oxygen. I felt like the whole room was spinning, even after I stumbled to my bed, lay down and closed my eyes.'

He recovered about 10 minutes later but had such attacks every few days over the next two months.

Unfortunately, an electrocardiogram (ECG) indicated his heart was normal, and the attacks stopped, so he dismissed them as signs of stress.

His daughter also began having attacks of breathlessness.

About six months before she died, Lyn could not make it home though she was already at the void deck. She called her father, who found her lying on the playground, unable to move.

She had also complained of breathlessness during jogging. But her ECG came back normal too.

Mr Low said: 'We thought it was due to exam stress, and lack of sleep. After her death, we were really regretful. Why didn't we get her to have more tests done, like the echocardiogram?'

Mr Low now takes medication daily to stabilise his heartbeat.

Whenever he feels his heart pounding harder than normal, he will take a break, wash his face, and tell himself to relax.

He said: 'I'm lucky to be alive. But if I had a choice, I'd rather have died, so my daughter could have found out about her condition, and lived.'

Change of lifestyle

For another patient, hypertrophic cardiomyopathy means that he can no longer pursue the passion of his life.

Mr William Ng, 43, a senior manager of a travel company, was a competitive marathon runner for more than 20 years, with some 40 marathons under his belt.

About 11/2 years ago, he started experiencing severe breathing difficulties while running.

He said: 'I wasn't just out of breath. I had to stop immediately because I was gasping for oxygen and my whole body felt weak.'

The attacks became more frequent, until they happened every other day.

After he was diagnosed, his doctor advised him to stop running. Even with medication, he sometimes feels breathless just sitting.

Mr Ng said: 'I felt very depressed. Running is my life. To ask me to cut it out completely is like losing an arm or a leg.'

He is trying to wean himself off running by picking up alternative sports such as badminton.

He used to train four times a week, running 5km to 8km on weekdays, and 15km to 20km on weekends.

Now, every week, he does just 5km at most, and at a deliberately slower pace.

He said: 'I'm very careful, and stop once I feel my heart fluttering or beating very fast. And I pray a lot before running.'

E-mail: huichieh@sph.com.sg