I couldn't believe what the cardiologist was telling me and, at first, I thought he was being overly dramatic.

After all, I was the fittest person I knew, an international athlete, who'd represented England in the 400m hurdles, not only at the Commonwealth Games in Manchester two years earlier in 2002, but also Great Britain at the European Championships in Munich the same year. 

Surely if I had a heart problem, I'd have collapsed by now?  But, as top cardiologist Dr Nigel Stephens warned me, I had to stop running straight away and would need further tests, the seriousness of my condition slowly sank in. 

Everything I'd ever worked for had suddenly fallen apart. 

I was suffering from what's commonly referred to as Sudden Death Syndrome, a term used for various causes of cardiac arrest in young people. 

Weeks of tests followed, and it was discovered I had a less-fatal problem than initially suspected, but the abnormality of my heart rhythm still meant I could no longer take part in any track and field events. 

I was devastated. 

My heart was beating very quickly at times, followed by a very slow beat, and it was this which was the worry, because it was possible the slow beat could have stopped my heart, resulting in cardiac arrest. 

It was so obvious to the cardiologist watching the ECG as I ran on the treadmill, and yet each time, he asked, "Can you feel that?", I couldn't. 

He and his team run the CRY - Cardiac Risk in the Young - Centre for Sports Cardiology at the British Olympic Medical Centre at Northwick, Park Hospital, in North London. 

Heart conditions like this aren't immediately obvious to the sufferer and, unless you're and athlete pushing your body to extremes beyond limits normally requested, abnormalities aren't always discovered. 

The average person could go about their daily lives oblivious to the fact they have a condition that's potentially so life-threatening. 

For me, it was only when my performance had begun to falter in 2004 and I was finding it harder to push myself and run times I'd easily run in previous years, that I decided to have myself checked. 

"The first course of action was to take medication for the heart rhythm, so two drugs were prescribed for around eight months, which slowed me down and, as well as making me feel tired, they also made me feel as if I might black out if I stood up too quickly. 

The weren't helping, but they had to  be ruled out before an operation. 

I was finally booked in for radiofrequency ablation, which kills the dead tissue in the heart. 

I have no idea how long my heart had been in this state as, until my first consultation, it had never been checked. 

The keyhole surgery in 2005 took place under a local anaesthetic, but it wasn't painless and, as the dead tissue was burned away, it felt as if my chest was on fire. 

Six weeks later, a check-up revealed it had been completely successful and, although this might sound strange, when I was told I had healed, it was almost as fear-provoking as the moment when I was told I was ill. 

Suddenly, I had to make a decision about whether or not to start running again, as there was no excuse not to. 

The fear of becoming ill again and maybe collapsing did haunt me for a long time, and I found my desire to compete had gone - maybe because I didn't feel athletics were worth dying for. 

"But I still had a huge void in my life, and in a way, I'm still trying to fill that. 

Initially, I quit the track and concentrated on my marketing carer. 

However, I couldn't get athletics out of my system so, at the start of the following year, I began training again with my athletic club, Woodford Green. 

The first time I ran around the track, I really felt I was home, and it was great. 

I've continued every since, and last July, ran in the 4 x 400m relay for my club. 

It may have been my slowest time every, but I still enjoyed myself and was very proud. 

Although I'm no longer an international athlete, I'm now competing at club level in national championships. 

And, for now, I'm content to keep enjoying it and not take it too seriously. 

I'm still only 28, which is at the older end for international level, but I haven't ruled this out completely. 

The charity CRY is one I've been involved with ever since I was first diagnosed, and I'm happy to support their work whenever I can. 

Raising awareness of these conditions has never been more important. 

With the current trend for so many people taking up running and entering local 5K and 10K races, we really need to make sure there's an efficient screening programme in place. 

People need to be made aware that, for £35 they could have a simple check to detect for any potential heart problem. 

The reality of the problem simply isn't hitting home because people always assume something like this only happens to other people. 

But as I know to my cost,  that simply isn't true. 

As told to Suzanne Roberts