It was an image that the world of football had hoped and prayed to never see again. As an unconscious Christian Eriksen received CPR on the turf of Parken Stadium, with his teammates attempting to form a protective ring to keep his motionless body out of sight, it was hard not to think back to Fabrice Muamba’s own collapse nine years ago.
The Bolton Wanderers player had suffered a cardiac arrest moments before half-time in an FA Cup tie against Tottenham. Just 23 years of age at the time, Muamba was technically dead for 78 minutes on that day in March, his heart no longer beating.
After 15 defibrillation shocks and extensive CPR — otherwise known as cardiopulmonary resuscitation, the application of downward thrusts to the chest to maintain the artificial flow of blood and oxygen from the heart — Muamba was brought back from the brink.
Like Eriksen, he had fallen to the pitch without any real indication of the internal trauma that had been inflicted. It was a moment that sent shockwaves across the sport, a harrowing reminder of the fragility of life — even at this elite level of the game, where footballers are rarely thought to be susceptible to such medical events.
But cardiac arrest can affect the healthiest of hearts, and is often triggered by a genetic abnormality — as was the case with Muamba.
Throughout the long history of top-level football, more than 80 players — all young men and apparently fit and healthy — are known to have died suddenly during a match. Hypertrophic cardiomyopathy was the cause in many of these cases. It is a genetic condition that one in 500 people carry and is linked to sudden cardiac arrest in young athletes.
Often hereditary, the condition is the result of a genetic mutation which causes the muscle wall of the heart to grow far thicker than it should. Intensive training and exercise can actually exacerbate the issue, causing the muscle wall to thicken to the point that the flow of blood into and out of the heart is impeded. If, in sudden moments of strain, cardiac arrest is triggered, the outcome can be fatal.
Marc-Vivien Foé, the Cameroon international and Manchester City midfielder, was found to have been suffering from hypertrophic cardiomyopathy after he collapsed on the pitch in a Conferations Cup match against Colombia in 2003. His death sent shockwaves around the footballing world.
At this stage, what specifically caused Eriksen’s sudden collapse remains unclear. In a statement released on Saturday evening, Uefa said the player had been “stabilised”, while the Danish Football Association (DFA) later said the player was “awake and undergoing further examinations” at Rigshospitalet — one of Denmark’s Denmark’s top cardiac units.
Peter Moeller, director of the DFA, said Eriksen — aged just 29 — received a "heart massage" while being treated on the pitch.
He was photographed with his eyes open and one hand on as his head as he was eventually carried off on a stretcher. The immediate treatment he received by medics at the Parken Stadium, in Copenhagen, likely saved his life.
It is the same story with the rapid response that followed Muamba’s collapse at White Hart Lane. Five fully medically trained assistants were pitchside that day, along with a St John Ambulance unit.
The availability of such services have not always been present in the game, though. After fracturing his skull playing against Reading in 2006, Chelsea goalkeeper Petr Cech was forced to crawl off the pitch by himself and wait for an ambulance.
An official Chelsea complaint led to an FA and Premier League review, which introduced new measures from 2007, including the requirement for every game to have an ambulance on standby for players and officials.
Other regulations made it compulsory for clubs to provide two paramedic stretcher-bearers, with a club doctor and physiotherapists on the team benches, as well as a qualified "crowd doctor" on standby.
Nonetheless, the nature of Eriksen’s horrifying collapse — and it’s apparent parallels with Muamba’s own experience in 2012 — will almost certainly refocus attention on what footballing authorities are doing to detect those dangerous genetic abnormalities and rare heart conditions which unknowingly threaten the lives of a small minority of athletes.
As Uefa and Fifa already require every player to be scanned ahead of a major tournament, it’s likely Eriksen will have been checked in the weeks before Saturday’s match.
In Italy, footballers already undergo a screening programme and simple heart tests to help detect hypertrophic cardiomyopathy.
The English FA meanwhile examines its junior professional footballers using an echocardiogram, which provides a detailed overview of the structure and function of the heart using ultrasound. It allows the precise measurement of heart chamber size, assessment of heart valves and adjacent blood vessels.
Greater scrutiny is also likely to be placed on the intensive playing schedule that footballers have faced in recent months. Just hours before Eriksen’s collapse, the footballers’ union Fifpro warned that player welfare was not being considered when competition calendars are drawn up.
"For the last four years ... players around the world have told us how the competition calendar does not adequately cater to, or even consider, their needs. Conditions in and around the game leave you mentally and physically exhausted," Fifpro general secretary Jonas Baerr-Hoffman said in an open letter. He said it was time for change and urged players to collectively make their voices heard through their unions.
For now, football and the wider sporting world must wait and watch for further news of Eriksen’s condition, and pray for a full recovery.