Christian Eriksen, the Danish soccer star who collapsed on the field during a European Championship match Saturday, suffered cardiac arrest before he was was resuscitated with a defibrillator, his team’s doctor said.
It remained unclear what caused Mr. Eriksen to collapse just before halftime. Denmark’s team doctor, Morten Boesen, who is not a cardiologist, declined to speculate. Nonetheless, sudden cardiac arrest has stricken competitive athletes in the past. And these much-publicized cases have highlighted the difference between sudden cardiac arrest, or SCA, and heart attacks.
Loyola Marymount University power forward Hank Gathers, Detroit Pistons G-league guard and forward Zeke Upshaw, and Boston Celtics shooting guard Reggie Lewis shared a talent for playing basketball. They also had a more tragic commonality – they all died after collapsing on the basketball court, all were under 30 years old, and all had heart conditions that caused their sudden cardiac arrest.
The Danish soccer star, Mr. Eriksen, remains in a Copenhagen hospital in stable condition. “He was gone. And we did cardiac resuscitation. And it was cardiac arrest,” Dr. Boesen, the team doctor, said in a videoconference with reporters. “How close were we? I don’t know. We got him back after one defib.”
SCA, such as what happened to these athletes, occurs when an abnormality of the heart causes it to stop beating, especially during or immediately after physical activity. The American College of Cardiology  estimates that approximately 100 to 150 sudden cardiac arrests, resulting in sudden cardiac death (SCD), occur in competitive sports each year in the United States. Often, lay people and the media erroneously report the cause of death in these cases as a heart attack. But sudden cardiac arrest is not the same thing as a heart attack.
Difference Between Sudden Cardiac Arrest and Heart Attack
“Heart attacks can cause a cardiac arrest,” explained Eli Friedman, M.D. , medical director of sports cardiology at Miami Cardiac & Vascular Institute, “that is, a blockage in an artery from atherosclerosis or a blood clot, can starve the heart of blood and oxygen and cause it to stop beating. But not all cardiac arrests are caused by heart attacks.”
Causes of Sudden Cardiac Arrest in Athletes
Dr. Friedman says that the cause of sudden cardiac arrest, especially among athletes under the age of 35, tends to fall into two categories: structural abnormalities or electrical abnormalities. They can be congenital, or present at birth, or they can be acquired as disease progresses or the heart is exposed to infection. These irregularities often go undiagnosed.
One structural and congenital condition that can increase the risk for sudden cardiac arrest is hypertrophic cardiomyopathy, in which the left ventricle, or lower chamber, of the heart is thickened or enlarged and prevents adequate blood from leaving the chamber on its path to the rest of the body. This can elevate the risk for arrhythmias, or irregular heartbeats, such as ventricular fibrillation, in which the heart’s electrical signals are disrupted, preventing it from beating in its normal rhythm and pumping enough blood to sustain life. Hypertrophic cardiomyopathy (HCM) is considered the No. 1 cause of sudden cardiac arrest for athletes under 35 years of age, according to 2020 statistics published by the American Heart Association . HCM led to Gathers’, Upshaw’s and Lewis’ sudden cardiac arrests, according to autopsy reports.
Other irregularities present at birth that have been shown to contribute to a higher risk for sudden cardiac arrest are abnormal arteries of the heart, called coronary artery anomalies, or CAAs. These abnormal arteries can be narrower than usual, or they can originate or end in nontraditional areas within the heart or leading to or from it. Coronary artery anomalies also lead to ventricular fibrillation and are the second leading cause of sudden cardiac arrest, according to the latest statistics published in March by the journal Circulation .
In structurally normal hearts, abnormalities of the heart’s electrical signals, which keep it beating, can also lead to sudden cardiac arrest. This category of disorders, called cardiac channelopathies, is characterized by abnormal heart rhythms and includes long QT syndrome (LQTS)  and Wolff-Parkinson-White syndrome (WPW) , which are diagnosed by an ECG. Dr. Friedman says that some research  indicates that these electrical abnormalities may be more prevalent in sudden cardiac arrest than is reported using autopsy reports and may actually be the No. 1 cause of sudden cardiac arrest.
Some conditions that can lead to sudden cardiac arrest may also be acquired. These include infections such as myocarditis and Kawasaki’s disease, which are characterized by inflammation of the heart muscle and blood vessels, respectively. New research related to COVID-19 indicates a link  between the novel coronavirus and myocarditis, although studies have yet to prove that the virus directly causes the inflammation.
Preventing Sudden Cardiac Arrest
Dr. Friedman says that preventing sudden cardiac arrest can be difficult, since most people with the above conditions may not be aware of them.
“Diagnostic tests, such as electrocardiograms (ECGs) and echocardiograms, can detect these conditions,” he said. “But the results aren’t conclusive that someone will suffer a sudden cardiac arrest. And the results in athletes, compared with the results of the average person, look different.” That can lead to unnecessary and expensive follow-up testing and can sideline an athlete when the results may be normal for someone who trains regularly. So, widespread screening among athletes is not recommended, he says.
Troubling Symptoms for Athletes
As a sports cardiologist who works with athletes and their tests regularly, Dr. Friedman doesn’t just look at the results of these tests to develop a plan of action for his patients. He also considers an athlete’s symptoms during or immediately after strenuous activity to determine how best to prevent any problems. Symptoms that show a potential problem, he says, include:
- Shortness of breath or fatigue that is not typical with the type of activity
- Pressure, tightness or pain in the chest
- Lightheadedness or fainting
- Heart palpitations or the sensation of your heart skipping beats
Even with a normal ECG (also referred to as an EKG) and echocardiogram, these symptoms may signal an underlying or undiagnosed condition that can lead to sudden cardiac arrest, so it’s important for athletes, coaches, trainers and parents to pay attention and report these to a doctor or healthcare provider.
First Aid for Sudden Cardiac Arrest
While sudden cardiac arrest in athletes remains rare, affecting a small percentage of the population, the dramatic scenes of seemingly healthy, revered athletes collapsing and dying in front of onlookers, drives Dr. Friedman’s passion to educate people how to respond to these tragic events.
Following the American Heart Association-recommended Hands-Only CPR , which has replaced traditional CPR that required giving mouth-to-mouth resuscitation, Dr. Friedman has taught many people affiliated with sports teams, athletes and parents how to perform lifesaving first aid.
“If you witness an unexplained collapse of an athlete, or anyone for that matter, assume it’s a cardiac arrest and take action,” he said.
Here are the steps he teaches to help save a life:
- Try to get a response by shaking the person.
- Check for a pulse.
- Instruct someone nearby to call 911 or do so yourself.
- Send someone else to grab an AED (automatic external defibrillator) if one is available or nearby.
- Begin chest compressions, pushing the chest down 2 to 2 ½ inches, 100 to 120 times a minute to the beat of the Bee Gees song “Stayin’ Alive” until the AED or paramedics arrive.
- Follow the instructions given by the AED, continuing chest compressions when advised to do so until emergency help arrives.
Research published in the April 24, 2019 edition of the Journal of Clinical Medicine  concluded that a key way to improve the survivability of athletes who collapse after physical exertion is to train individuals to identify a possible sudden cardiac arrest, activate first responders, perform chest compressions and use an AED.
Coming Soon: Community-focused CPR and AED Training
Dr. Friedman and the sports cardiology team from Miami Cardiac & Vascular Institute are developing a sports-focused CPR and AED training program for coaches, parents, athletic trainers and community members, as well as youth and student athletes. This program, set to launch in the summer, will teach participants from teams, leagues, parks, gyms and schools, as well as running, cycling and triathlon training groups, how to recognize a possible sudden cardiac arrest and respond with lifesaving aid. Participants will learn hands-only CPR and how to use an AED until medical help arrives.
“Surprisingly, only 50 percent of youth coaches are trained in CPR and AED use,” Dr. Friedman said. “We’re looking forward to changing that statistic in South Florida.”