Steven is the 19-year-old son of Mark Cox, for many years the UK's number one player and now a respected commentator. Steven was so talented that he won a tennis scholarship to a US university, where he was one of the most promising students. But after a routine health check given to everyone on the course, a cardiologist told him - brutally, and with no preparatory preamble: 'You will never play tennis again'.
There followed a testing time for the young athlete, who had believed he was at his physical peak. He endured electrocardiograms, angiograms, even the trauma of a heart biopsy when a sliver of his heart was rushed back to the UK to be examined by experts. Then came the confirmation: he had a type of cardiomyopathy - a heart muscle disease which is the leading cause of death in young athletes and of Sudden Death Syndrome in seemingly healthy adults. Some experts believe that between 10,000-12,000 people in Britain may be affected to some degree.
There are three major types of the condition, the most common being hypertrophic cardiomyopathy (HCM). With this, the heart muscle thickens abnormally and the cells appear disorganised, contributing to irregularities in the heart beat. In some cases, the heart muscle bulges and obstructs the smooth working of the valves. All three types can lead to sudden cardiac arrest.
Why should a disease target the young and fit in this way? Since thickening of the heart muscle is frequently seen in top athletes, it is tempting to see a connection between cardiomyopathy and excessive training. Yet there is no evidence for this. 'We see a lot of patients with HCM who are totally inactive,' says Dr Ulrich Sigwart of the National Heart and Lung Institute, who is about to reveal a new non-surgical technique for treating advanced cases. 'It's just that the fittest are more likely to die because of the amount of exercise they do.'
Professor Richard Goodwin, president of the Hypertrophic Cardiomyopathy Association, agrees. 'There has been no suggestion that exercise causes or hastens the progress of the disease,' he says. But the number of promising young athletes who die unexpectedly suggests a need for further investigation.
Footballer Terry Yorath's son Daniel, for example, died of HCM two years ago while kicking a football with his father; he had just signed for Leeds. Now Terry and his wife Christine are campaigning for greater awareness of the syndrome. Only last month, 14-year-old Andrew Lightwood died suddenly while playing cricket in Staffordshire, and 15-year-old Ashley Walker collapsed and died a few days later after leading his cricket team to victory in a schoolboy cup in Sunderland.
The parents of both boys were at first told that their super-fit sons might have been suffering from viral pneumonia. But Professor William McKenna, an authority on cardiomyopathy who is often consulted on such sudden deaths in Britain, disagreed. 'You don't die suddenly from viral pneumonia. What's more, if you do have viral pneumonia you have symptoms - such as a fever and a cough - and you are bed-ridden, not playing cricket.' Both boys, he says, must have had some underlying cardiac problem.
Professor Goodwin - a member of the 'sudden death committee' of the new National Sports Medicine Institute, at St Bartholomew's Hospital, London, which has made HCM its top priority - also disagrees with the viral pneumonia diagnosis. 'There would have had to be a virus attacking the heart - or an underlying heart condition. While it is not wise to speculate without full knowledge, these seem like classic cases of HCM.'
Yet HCM is difficult to diagnose, and misconceptions about it abound. 'One GP told a mother whose son had died that it was a 'one in a million' chance and unlikely to happen again in the family - which was horrendous,' says Alison Cox, mother of sufferer Steve. 'Everyone in that family was at risk. Another woman's nine-year-old son had symptoms and was examined by a consultant who thought he had asthma and didn't bother to screen him. He was very keen on running and the consultant said: 'The best thing he can do is keep running'. He died on his next school run.'
HCM can be particularly difficult to pick up in young children, as the thickening of the heart which characterises the condition may not be visible to ultrasound equipment at that age. It generally worsens with time, often dramatically during the growth spurt of puberty, Professor Goodwin explains. The youngest child of footballer Terry Yorath will have to be screened regularly from now on, even though his sisters (aged 20 and 21) have been cleared.
But how much is actually known about the causes of HCM? 'We know with certainty that at least 50 per cent of HCM has a familial basis,' Professor Goodwin says. His own belief, based on 30 years of work, is that all cases are probably hereditary - although the condition can skip generations.
'There seem to be a number of genetic abnormalities involved,' he explains. 'It's possible to screen for them using blood tests, but not on a routine basis. There are only a very few places doing them.' In the future, however, it should be possible to pick up the genetic marker for HCM using a single test - 'but we'd still need other tests to monitor the progress of the disease,' says Professor Goodwin.
Predicting who may be susceptible to cardiomyopathy is at present laborious, time-consuming and stressful. The first step is to look at family history - any relative who may have died suddenly and unexpectedly. If a clinical examination fails to find any other cause, the patient undergoes various tests to monitor heart rhythm and pick up abnormalities such as thickening of the heart muscle. Finally, and only in very rare cases, a heart biopsy - an invasive and risky procedure - might be undertaken. British doctors seldom advocate this.
Where vulnerable youngsters are involved, consideration must be given to the psychological effects of screening. 'One of the rules,' Professor Goodwin says, 'is that you mustn't screen for something that will only cause anguish, and about which you can do nothing. We're very concerned not to produce anxiety, which can be so common anyway among people in their early twenties.' Because some of them are so keenly committed and almost obsessed by their sport, they may reject the HCM diagnosis completely or become hostile. Professor Goodwin recalls one man 'who was diagnosed, given the right treatment, said 'the hell with you', and went on playing high-level professional football until he dropped down dead'.
Lizzie Webb, the former TV-am fitness expert who now runs her own health club, knows only too well how a sport- loving youngster can be devastated by news of a heart condition. Her 17-year- old son Ben is a promising rower in the Great Britain junior squad, and won a cup at Henley this year. Watching him train so intensively reminded Lizzie that her father had died suddenly of a heart problem which, according to his doctor, might have been inherited. 'When I saw what a strain his heart was under, in one of the most intensive cardiovascular
sports,' she says, 'I suddenly felt guilty about not having had Ben tested.'
Remembering the sudden death of Terry Yorath's son, she arranged a full medical without telling Ben why. He was pronounced perfectly healthy. Two weeks later, however, Lizzie was told to have her son checked by a cardiologist because there was a complication. His heart beat was irregular and slow at rest, although his ECG was normal during exercise. 'He was either supremely fit,' Lizzie says, 'or there was something seriously wrong.'
During the next punishing round of tests, she had to prepare Ben for the fact that his life might change. Treatment nearly always means giving up all rigorous, competitive sport and a regime of beta blockers, stabilising drugs or an electronic pacing system. If a bulging muscle is causing an obstruction, tissue may have to be surgically removed. After weeks of tension, Ben was given a complete all-clear. 'Professor William McKenna (Ben's cardiologist) said his heart beat was so slow because he was such a highly-trained athlete. I'd never have let him continue if there had been the slightest doubt.'
The new National Sports Medicine Institute is campaigning for a national screening programme for young people. Already Professor McKenna has screened all top British tennis players. Professor Greg McLatchie, a former boxer who is a professor of sports medicine and the institute's director, says: 'If youngsters like Daniel Yorath are worth millions to a football club, why aren't they automatically screened? We have a pilot scheme screening fit young people between the ages of 15 and 35 in Glasgow, the heart disease capital of Europe. We've established 22 centres around the country where people can get clinical support, advice and education, and use the institute as a central database.'
Alison Cox continues to raise money for a mobile testing unit to visit schools and sports clubs. 'The funding I'm getting is for screening to cover any electrical defect of the heart for young people, which these tests would pick up,' she says. 'One of our top junior tennis players dropped dead a couple of years ago from a faulty valve, which would have been picked up in this screening process.'
But what is the prognosis for those youngsters already diagnosed as suffering from HCM? Gentle, non-competitive exercises such as swimming, golf, archery, bowls, riding and skating are permitted - but as Alison Cox observes: 'A competitive sportsman like Steven would be competitive playing marbles.' Professor Goodwin acknowledges that psychologically stressful situations are also likely to bring on a sudden death; the frustration of talented young athletes watching life pass them by can be intense: 'Lots of reassurance and counselling is needed.'
Certainly, nobody should ever have the news broken to them the way Steven Cox did - by a doctor his mother will never forgive. But Steven is one of the lucky ones. As Terry Yorath says: 'I'd rather have had a son who was alive and couldn't play football - and I'm sure that if we'd known, we could have made Daniel see that. Initially it would have crucified him, but with the intelligence he had he would have understood.'
The Hypertrophic Cardiomyopathy Association, is based at Waverley, Lodge Drive, Rickmansworth, Herts WD3 4PT (0923 896776).