Daniel du Plessis had been on the field for a few minutes when he collapsed just before a scrum during a Currie Cup under-21 match between Western Province and the Leopards on Saturday last week. Paramedics and team doctors rushed onto the field, and their expert support ensured that the 20-year-old hooker was first defibrillated (his heart basically "jump started" by the electrical pads made famous on TV shows), stabilised and then taken to hospital where he was placed into an induced coma.By Monday, he was off the ventilator, sitting and talking, his recovery thankfully under way.Du Plessis suffered from cardiac arrest, which is best understood as a failure in the electrical circuit of the heart. It causes normal heart rhythms to be disrupted, and the heart begins to flutter rather than beat, its normal pumping action failing. The outcome is usually death.Sudden cardiac death occurs in about one in 50000 people playing sport a year. That might not sound like much, but with hundreds of schools playing dozens of sports, it means that statistically, events like Du Plessis's cardiac arrest are inevitable - the US has about 150 young athletes dying every year, South Africa might expect five to 10.The sight of a professional athlete experiencing cardiac arrest during a sporting event registers disproportionately on our "shock sensors", because sport is meant to showcase athletic excellence, not human frailty. In addition, that these incidents are often played out in front of thousands of fans and on potentially hundreds of thousands of TV screens amplifies their societal impact even more.In 2012, in perhaps the most high-profile case in recent years, Fabrice Muamba collapsed while playing for Bolton Wanderers in the English Premier League.Like Du Plessis, he received excellent medical care (including support from a cardiologist who was in the stands as a fan).Though his heart stopped beating for an astonishing 78 minutes and he spent a month in hospital, he recovered.But his professional football career was over.Others have not been as fortunate. On April 14 2012, 25-year-old Italian footballer Piermario Morisini collapsed while playing for Livorno in the Italian Serie A. He could not be resuscitated. His death triggered an outpouring of grief, followed soon after by questions about the responsibility of care that sport has towards its athletes.The reality is that athletes are far less likely to suffer cardiac arrest (and a host of other diseases, hence the benefit of sport) than the non-athletic population, but it is often playing the sport that triggers an underlying condition to cause the event. That is, there are a number of conditions, mostly genetic, that increase the risk of cardiac arrest in certain individuals.The great problem is that they often go unnoticed, with the first indication of a problem being death. In other words, people cannot see death coming, and when they do, it is often too late.The prospect of identifying athletes who are at risk as a result of these conditions is obviously compelling - a life saved would be worth the investment. The reality is a little more complex.Cardiac screening is enormously expensive, and while it might sound callous to put a financial figure on this, the tests often aren't sensitive enough to identify all the risks, and sometimes, they falsely identify a person at risk.They therefore provide uncertain answers, with limited practical solutions.There's no "cure", just avoidance, and players might not want to know this.What is undoubtedly true, and the Du Plessis case illustrated this, is that the best means of avoiding the trauma of sudden cardiac death is expert medical care. The chances of surviving cardiac arrest increase from about 5% to over 50% if medical care is rapid and high quality, which includes having defibrillation equipment on hand.Any school, organisation or person hosting a sports event must ensure that they have these facilities at their disposal, because they are literally life or death investments. Daniel du Plessis could be the face of that realisation, and the source of many saved lives in future...