The Sudden Cardiac Arrest Foundation describes SCA as "a healthcare crisis", adding that the number of people in the United States who die of it each year is "roughly equivalent" to the total who die for the combined reasons of Alzheimer's disease, assault with firearms, cancer, diabetes, HIV, house fires, car accidents and suicides.

But the difficult news to take in as far as competitive sportsmen and women are concerned is this: according to the Physicians' Health Study, the risk of sudden cardiac death increases 11-fold among those who exercise regularly and vigorously.

New Zealand schoolgirls rowing this month ©Getty Images

The condition is not caused by the physical activity, but if an athlete has a hidden pathology of a heart condition, then working strenuously can exacerbate it, often with fatal results.

SCA is not the same as a heart attack. The latter is more of a "plumbing problem" in the heart, which may be blocked. Those suffering heart attacks are usually awake and aware of what is happening.

By contrast, SCA is like having an electrical failure. It is a sudden pulseless condition which is usually caused by ventricular fibrillation, an abnormality in the heart's electrical system. When SCA occurs, blood stops flowing to the brain, the heart and the rest of the body, and the person collapses. The victim is clinically dead, and requires immediate assistance in the form of cardiopulmonary resuscitation (CPR) or the use of an automated external defibrillator (AED).

The three most common conditions which can lead to SCA are a thickened heart muscle (eg hypertrophic cardiomyopathy), heart rhythm disorders (eg long QT syndrome) or heart valve disorders (eg mitral valve prolapse). Some of these conditions can be genetically inherited.

The latest plans have been made in the wake of several high-profile instances where top class rowers have been affected by heart problems.

Greg Searle, who won gold in the coxed pair for Britain at the Barcelona 1992 Olympics and returned at the age of 40 to take bronze in the eight at the London 2012 Games, discovered last year that he had a heart condition when he went to complete a triathlon in Italy, where screening is compulsory.

The results showed that he had atrial fibrillation - a condition that also affected British Olympic champion Tom James while he was training for London 2012. James, who announced his international retirement last year, managed the condition sufficiently well to win a second Olympic gold in the four, defending his Beijing title.

British rower Tom James successfully managed a heart rhythm disorder before winning a second Olympic gold at London 2012 ©Getty Images

A step test during screening saw Searle's heart beat jump to 240 beats per minute. Consequently Searle was not allowed to compete in the triathlon. "I've had electric shock which has put my heart back into rhythm," says Searle. "So it's normal now but I have to be careful." Searle has had no incident since but has been advised to be careful with alcohol intake and also in doing endurance sport.

Both Searle's father and uncle have the same heart problem and Searle has been prescribed Warfarin, a blood thinner. If Searle had not been screened the consequence could have been a stroke.

In 2009, Searle's 25-year-old Molesey clubmate Scott Rennie, who was on the fringe of selection for Britain ahead of the London 2012 Games, collapsed and died while training on a rowing machine at the club. It was found he died of a previously undiagnosed heart condition.

At the time, another Molesey club member, Andy Triggs Hodge - who earned a second Olympic gold alongside James in the four at London 2012 - called for routine screening for all young people, lobbying MPs after becoming patron of the charity Cardiac Risk in the Young (CRY).

"Scott was a great athlete, at the peak of his fitness," Triggs Hodge said. "No one knew there was a problem with his heart and his death had a devastating effect on his family. All who knew him found it impossible to believe that such a young man could die in this way. But as a patron of the charity CRY I have the opportunity to raise awareness of their great bereavement work and their programme to screen young people for heart defects."

Four years earlier, 29-year-old Canadian international rower Kiran van Rijn died after losing consciousness while training in a single scull. The autopsy revealed that Van Rijn had an underlying and unknown pathology of hypertrophic cardiomyopathy.

New Zealand rower Rob Waddell moved into single sculling after he was diagnosed with arterial fibrillation, as he did not want to be in a team boat where he might let team mates down. He went on to win gold at the Sydney 2000 Olympics.

However, when Waddell attempted a comeback in the single in 2008 his heart let him down. In a head-to-head race with Mahé Drysdale to help decide who would be chosen as New Zealand's Olympic single sculler, Waddell was barely able to finish the 2,000 metres race.

The suffering is clear on Rob Waddell's face after his testing final race against Mahé Drysdale on Lake Karapiro in March 2008 ©Getty Images

Auckland City Hospital cardiologist Dr Chris Ellis told the New Zealand Herald at the time that atrial fibrillation was the commonest heart arrhythmia.

"It's actually very common, and a lot of GPs and cardiologists would be seeing these patients all of the time.

"You can lose up to 25 per cent of your cardiac efficiency. There's a whole lot of reasons why you might jump into atrial fibrillation. Common reasons are to have high blood pressure, hardened arteries, leaking valves, holes in the heart, and a variety of other conditions.

"So for Rob Waddell, and people like him, and some endurance athletes, they just leap into this rhythm as they push the heart really hard."

He added that physical exertion could bring on an episode, but not always.

"Obviously it doesn't a lot of the time, otherwise he wouldn't have won the Olympic gold [in 2000].

"He's obviously got one of the strongest hearts in New Zealand, but electrically it's rather excitable and jumps out of rhythm once in a while. For older patients, if they aren't well-treated, some of them can have strokes as a result of it."

He also said he admired Waddell for talking publicly about his condition.

"It's very helpful and should be congratulated because it means that other people who have got this issue can understand that they've got a wonderful heart, very often, which is just electrically a little unstable," Ellis said.

Waddell went on to compete at the Beijing Olympics in the men's double. Then in 2009 he had an operation to correct his heart problems.

Recently, London 2012 Olympic champion Nathan Cohen of New Zealand discovered that he had supraventricular tachycardia (SVT). This is when the rhythm of the heart suddenly changes.

Nathan Cohen was forced to miss last year's World Championships when a heart irregularity showed up ©Getty Images

For Cohen, who was 27 when the condition occurred, it meant not competing at the 2013 World Rowing Championships.

"It feels like your oxygen is running out, you lose power and become weaker, like you're dragging something behind the boat," Cohen told the New Zealand Herald at the time.

"When an athlete gets older they can get an absolute arrhythmia (irregular heartbeat of the atria by dysfunction of sinus node) which is different from Nathan's condition," said FISA Sports Medicine Commission member Dr Jürgen Steinacker, who specialises in cardiology. "The risk is somehow higher in athletes than the general population. But despite this rowers have a high life expectancy.

"Normally arrhythmia problems don't have a genetic trait. So you can't say whether your son or daughter will have it as it's to do with the development of the heart. It can occur from hypertrophic heart walls, a condition when arterial hypertension is not treated or from previous viral infections.

Steinacker added that studies have shown that the mandatory screening done in Italy has meant the rate of Sudden Cardiac Deaths (SCD) has diminished by 50 per cent. "In most cases of athletes dying of SCD it has been unnecessary. You can't prevent everything but you can prevent SCD."

Now FISA has taken its own proactive stance to reduce risk among rowers of "Sudden Cardiovascular Death in Sport (SCD)."

FISA is introducing a pre-competition health screening process that will be introduced in stages. This screening process has been designed by experts to identify as accurately as possible athletes that may be at risk of heart problems and advise them accordingly.

Screening will apply for all rowers competing in the 2014 World Rowing Junior Championships. In 2015 screening will apply to all rowers competing in the Junior, Under-23 and Senior World Championships. For all other events including masters, coastal, indoor and touring screening of rowers is strongly recommended.

IOC medical and scientific director Richard Budgett, a 1984 Olympic gold medal winning rower alongside Steve Redgrave in the four, praised FISA's stand saying, "The IOC published a consensus statement on Periodic Health Examination in 2009 as part of its strong commitment to protect the health of athletes. The introduction by FISA of mandatory pre-competition health screening is an excellent initiative that puts into practice the principles of the consensus statement.

Richard Budgett,an Olympic gold medallist in 1984, has spoken in favour of the health screening ©Getty Images

"The new bylaw promotes good medical practice throughout the sport of rowing and thus is a significant step forward in the protection of athletes' health."

FISA Sports Medicine Commission member Dr Mike Wilkinson adds that most heart conditions are pre-existing. The most common is hypertrophic cardiomyopathy. "Very often an athlete can continue for their whole career and never know that they have a predisposition, or the first time they know is when they collapse. If screening is done then it's the most cost effective way of picking up abnormalities."

Writing in the February issue of Rowing Magazine, Heather Cartwright - a former Canadian rower who has since coached in the United States at Princeton, Boston University and Harvard - recalls her own experience of a cardiac dysfunction in 1990, when she was a 20-year-old with ambitions of selection for the 1996 Olympic team.

She was forced to give up rowing - and any sports which raised her heartbeat over 85 beats per minute - after being diagnosed with a rare genetic condition known as arrhythmogenic right ventricular cardiomyopathy.

Cartwright, however, goes on to highlight potential problems raised by screening. The first has been a reluctance, in some parts of the sport, to countenance it. She cites the comments of a cardiologist, Santosh Menon, who offered free heart screenings last June for US high school rowers, who experienced resistance from both coaches and parents.

One of the other major factors militating against the introduction of mandatory testing is the huge cost such a move would incur.

The Italian lead on screening has produced unarguable results. Since mandatory ECG screenings for all competitive athletes between 12-35 were introduced in 1982, the mortality rate of young Italian athletes has dropped by 79 per cent.

But Cartwright makes it clear that screening in itself is not always the answer - correct interpretation of data being as crucial as the gathering of data in the first place.

She raises research done in the 1890s on Harvard rowers which concluded that the sport was injurious as it caused the heart to increase in size. Nowadays this is regarded as a perfectly healthy result of sustained exercise.

Cartwright also cites the example of US rower Kate Bertko, who suffered irregular heartbeats and dizziness that eventually caused her to collapse after a race. At one point, ten doctors were said to be involved in offering diagnoses, and Bertko was said eventually to be suffering from long QT syndrome, a potentially fatal heart rhythm disorder.

Kate Bertko, right, went through agonies after misdiagnosis of a heart condition which proved unhazardous - as she showed in winning silver at last year's World Championships ©Getty Images

Bertko was unwilling to accept this diagnosis, however, and sought another medical opinion which correctly diagnosed her condition as atrial fibrillation - the same condition James successfully managed.

Bertko, who went on to win silver in the lightweight women's double with Kristin Hedstrom at last year's World Championships in South Korea, commented: "If the doctors weren't so alarmist, it could have been different."

In conclusion, Cartwright calls for more AEDs to be on hand close to rowing venues, and for more people to become aware of how to administer CPR.

"More discussion is warranted regarding mandatory testing as a preventative option," she writes.

Mike Rowbottom, one of Britain's most talented sportswriters, covered the London 2012 Olympics and Paralympics as chief feature writer for insidethegames, having covered the previous five Summer Games, and four Winter Games, for The Independent. He has worked for the Daily Mail, The Times, The Observer, The Sunday Correspondent and The Guardian. His latest book Foul Play - the Dark Arts of Cheating in Sport (Bloomsbury £12.99) is available at the insidethegames.biz shop. To follow him on Twitter click here.