How Eriksen's heart device worked: living and competing with an ICD

The cardiac incident Christian Eriksen suffered during a Denmark friendly briefly returned an unusual piece of medical kit to centre stage: the implantable cardioverter-defibrillator, or ICD. The BBC reports that the device fitted to the midfielder after the 2021 Euro tournament kicked into action this time, and that he was stable after treatment.

An ICD is a unit roughly the size of a small mobile phone, implanted beneath the skin near the upper chest with leads that run into the right side of the heart. It monitors the cardiac rhythm continuously and, when it detects a life-threatening arrhythmia such as ventricular tachycardia or fibrillation, delivers an electrical shock within milliseconds to restore normal rhythm. Eriksen's ICD reportedly intervened on this occasion.

Professor Vassilios Vassiliou of the University of Manchester told BBC Sport that ICDs have been a standard protective tool in cardiology for years. He explained that placing one in an elite-level athlete requires careful, case-by-case review of every return-to-play decision, since training loads can affect both battery life and signal quality from the leads.

Returning to professional sport with an ICD has become an accepted approach over the past decade. European Society of Cardiology and American College of Cardiology guidelines indicate that athletes with an ICD may continue lower- to moderate-risk sports, provided they have long-term specialist monitoring and close coordination with the team's medical staff. Contact sports may require additional protection over the device's housing.

After Eriksen's original 2021 incident, Italian football association rules ruled out an immediate Serie A return, but he was able to play under Premier League rules in a career that reached Manchester United. Updates carried by the BBC indicate that the player's condition is stable and that the club and national-team medics have confirmed the device performed its expected protective role.

The evidence base for ICDs in athletes has grown steadily. The 2017 ICD Sports Safety Registry, which followed 440 athletes who returned to competitive sport, suggested that the risk of serious device malfunction or inappropriate shocks remained limited across five years of follow-up. Specialists still recommend that every case be evaluated under an electrophysiologist's supervision.

Some professional football clubs run specific protocols for players with ICDs. These include device programming calibrated for training intensity, automated telemetric checks, and even tighter standards for match-day defibrillator and cardiologist availability. UEFA reviewed its in-stadium emergency-response protocols after the 2021 incident.

Other examples of footballers continuing to play with an ICD exist. The Netherlands international Daley Blind had a device fitted in 2019 after a cardiac rhythm issue and went on to play for Ajax and Manchester United. As the BBC notes, the Blind case is among the practical examples that have helped build the cumulative evidence base used by cardiologists and athletes today.

From the patient's perspective, the physical sensation of a shock can vary. Some users describe it as a sharp kick in the chest. After any intervention, a follow-up with a cardiologist is mandatory. In Eriksen's case, the medical teams reportedly began structured assessment immediately after the on-field event.

The BBC's piece underlines that the ICD is not just an emergency rescue tool but the product of decades of cardiology research now operating at the edge of elite sport. Eriksen's case illustrates both the device's protective role and the importance of the rigorous monitoring protocols that athletes are expected to follow. This is not medical advice.