CONCERN: Byun Sung-hwanTHEY are three names that will mean little to most Australian sports fans – Marc Vivien Foé, Phil O’Donnell and Anthony Van Loo.

But as Jets defender Byun Sung-hwan awaits the result of medical tests that have cast a cloud over his professional career, the stories of three fellow footballers warrant close consideration.

Byun was stood down from training on Tuesday after an electrocardiograph (ECG) test, which all players underwent in the pre-season, revealed he had left ventricular hypertrophy, or an enlarged left ventricle.

The condition can occur naturally as a reaction to aerobic exercise and strength training. But it can also be a symptom of a rare genetic disease known as hypertrophic cardiomyopathy (HCM), which in extreme cases can cause heart failure, especially during intense exercise, and prove fatal.

Jets officials did not want to speculate on Byun’s condition or jump to false conclusions until they had considered all the information available.

CEO Robbie Middleby said Byun’s welfare was their primary concern, but if he received appropriate clearances, there was a chance the Korean could play against Central Coast tomorrow in the F3 derby in Gosford.

The 32-year-old has experienced no episodes that would suggest he has a potentially life-threatening condition.

But neither did Foé nor O’Donnell, both of whom are remembered more for the tragic circumstances in which they died than their impressive careers.

Foé was a Cameroon international who played for West Ham and Manchester City in the English Premier League.

In June 2003, while representing his country in a semi-final of the Confederations Cup, he collapsed on the pitch and died, despite attempts to revive him.

An autopsy revealed the 28-year-old had unwittingly suffered from HCM.

O’Donnell was a former Scotland international who played for Motherwell, Celtic and Sheffield Wednesday.

In December 2007 he was playing for Motherwell against Dundee United and collapsed just as he was about to be substituted.

The 35-year-old father of four was rushed to hospital but died. A post-mortem indicated his death was caused by left ventricular failure, believed to be as a result of HCM.

After the deaths of Foé and O’Donnell and other such tragedies, football clubs around the world started to test their players for heart defects.

It was such a screening process that may have saved the life of young Belgian defender Van Loo.

In 2008, when he was playing for Belgian second-division club Roeselare, the 20-year-old collapsed to the turf unconscious. But as teammates rushed to help him, Van Loo visibly jolted on the ground and slowly regained his feet.

He was taken to hospital but returned after the match to join in his team’s victory celebrations.

Van Loo’s life had been saved by a defribillator, implanted in his chest six months earlier when he was diagnosed with HCM.

Defribillators contain a small computer that detects when a heart loses its rhythm, often causing a blackout, at which point a life-saving electric shock is delivered.

After the remarkable incident, which can be seen on YouTube, the club doctor said: ‘‘There was a moment of panic, but the device saved his life.’’

Van Loo, a Belgian under-23 representative, now plays in Belgium’s top football league.

There has been no confirmation that Byun has HCM.

Middleby said the Jets would wait until they had received all medical advice.

‘‘Then we will sit down with all the doctors and specialists and consider all the options,’’ he said. ‘‘If there is any risk, we want him to know what it is and do the right thing by him.’’

He said communal heart screening had been ‘‘recommended’’ by Football Federation Australia, but the Jets ‘‘haven’t done it in the past’’.

This year, the club decided it was a better policy to be safe rather than sorry.

And at least one of their players may have cause to be grateful for the rest of his life.