Screening potential to cut cardiac deaths in young athletes 'likely to be low'
The moment that professional footballer Fabrice Muamba collapsed on the pitch during a match is an image that is seared into the memories of many fans.
The midfielder collapsed following a cardiac arrest while playing for Bolton Wanderers against Tottenham Hotspur in an FA Cup match in 2012.
While the former player made a miraculous recovery after his heart stopped beating for more than an hour, others who suffer sudden cardiac arrest are not so lucky.
But now experts have said that young athletes should not undergo screening to prevent sudden cardiac arrest.
They argue that even though the sudden cardiac death of a seemingly fit person on a sports field is a "devastating event", there is no evidence to support pre-participation screening.
The potential that screening has to reduce deaths is "likely to be low", according to an analysis of the available evidence published in The BMJ.
The Belgian authors argue that there is a poor detection rate and it can lead to some athletes being misdiagnosed.
Receiving a false positive result could mean a young athlete is prevented from participating in competitive sport for life and it may lead to young people avoiding exercise altogether, they said.
Sudden cardiac death can be caused by a number of rare genetic problems and other heart disorders that are present in around 0.3% of the population.
Most affected people are not aware of disease but some develop symptoms such as dizziness, fainting or breathlessness - which can lead to a diagnosis.
The authors point out that in around 1% of young athletes with unrecognised heart disease, sudden death will be the first and only manifestation of the disease. It is these people that screening aims to detect.
In the UK, the charity Cardiac Risk in the Young runs screening events, but the National Screening Committee decided last year not to recommend a population screening programme, the authors said.
"Sudden cardiac death of a young person on a sports field is a devastating event. Often these deaths are due to an unrecognised underlying heart condition, and screening has been proposed as a method to prevent them," the authors wrote.
But they conclude: "The effectiveness of pre-participation screening in reducing the number of sudden cardiac deaths among young athletes has not been substantiated by solid evidence.
"Its potential to reduce deaths is likely to be low because of the poor detection rate and the uncertain effectiveness of the management of the diseases thus identified in asymptomatic people.
"Pre-participation screening induces harm because of the high number of false positive test results leading to temporary or lifelong disqualification from competitive sports, psychological and financial harm, and medical follow-up and treatment with unknown benefit.
"In addition, it leads to young people avoiding exercise known to be beneficial to their overall health. As long as those at high risk of sudden death cannot reliably be identified and appropriately managed, young athletes should not be submitted to pre-participation screening."
They said that the exact number of sudden cardiac death in young athletes is not known, but a recent review by the National Screening Committee suggested an annual incidence of one per 100 000 people aged 12 to 35.
Earlier this month England and Nottinghamshire cricketer James Taylor was forced to retire due to a rare heart condition.
The 26-year-old batsman has been diagnosed with ARVC (arrhythmogenic right ventricular cardiomyopathy), an inherited condition caused by a change or mutation in one or more genes.
It means the right side of his heart fails to pump blood around his body properly and it can cause abnormal heart rhythms. The condition is progressive, which means it will get worse over time, and there is a risk of sudden death.
Cardiac Risk in the Young (CRY) chief executive Dr Steven Cox said: "Cardiac screening saves lives - fact, both amongst the elite sporting community and the general population.
"CRY's pioneering screening programme now tests around 23,000 young people aged 14 to 35 from both of these groups and one in every 300 people tested by CRY will be diagnosed with a potentially fatal - and more than likely, treatable - heart defect.
"Every week in the UK, at least 12 young people under the age of 35 die suddenly from a previously undiagnosed heart condition. 80% of these deaths will occur with no prior symptoms or warning signs which is why expert screening is so vitally important. Sport itself does not cause these deaths but in some cases, it can exacerbate an existing problem.
"We have numerous examples of young people who have been identified with potentially fatal heart conditions through screening - and who wouldn't be alive today if they had not been successfully identified and treated."
Professor Peter Weissberg, medical director at the British Heart Foundation, said: "Ideally, there should be an accurate and reliable test to identify those very few young sportspeople who are at risk of sudden death from an underlying heart condition. However, as this study shows, the current diagnostic tests are not yet sufficiently reliable. This means that some individuals who are at risk may be missed, and many more may be falsely identified and have their lives blighted by undue concern and long-term medical follow up.
"Until research can find better ways of identifying people with these conditions, it is essential that appropriate genetic cascade testing is performed on those with family members known to have inherited heart conditions. The British Heart Foundation is funding research to improve diagnosis and treatment of inherited heart conditions and is raising money through the Miles Frost Fund to roll out cascade genetic testing services across the UK."