How can athletes play with ICDs, and what happens when one goes off?Image source, Getty ImagesImage caption, Christian Eriksen is Denmark’s record appearance-makerByDaniel AustinBBC Sport senior journalistPublished1 hour agoWhen Christian Eriksen collapsed during Denmark’s 2-1 friendly victory over Ukraine on Sunday, he was assisted by a device which was fitted to support his heart after he suffered a cardiac arrest during a Euro 2020 match.
The implantable cardioverter defibrillator (ICD) sits in Eriksen’s chest, with wires connecting it to his heart. It provides a shock to either restart the heart if it stops beating, or to jolt it back into a regular rhythm if abnormalities are detected.
“The pacemaker responded as it should,” mentioned Denmark’s national team doctor Morten Boesen on Sunday.
The sight of Eriksen dropping to the turf, before being surrounded by visibly upset team-mates while being treated by medical staff behind a makeshift curtain, was frighteningly reminiscent of his previous collapse, which shocked football fans around the world.
So, how can athletes return to elite-level sport after having an ICD fitted, what are the risks, and what happens when the device goes off?

