- Bronny James was hospitalized with cardiac arrest and is now reportedly in a stable condition.
- Cardiac arrest rates are not common among young athletes.
Bronny James — LeBron James's son who is a rising basketball star at USC — was hospitalized with cardiac arrest on Monday, according to a statement tweeted by NBA writer Shams Charania.
The 18-year-old, who has since been discharged from the ICU in a stable condition, had no known underlying medical concerns.
However, cardiac arrest is not unheard of in sports. A number of athletes have experienced cardiac events on the field, as Insider's Gabby Landsverk reported.
Dr. John P. Higgins, a sports cardiologist with the Houston Rockets and a professor of cardiovascular medicine at UTHealth Houston, said in a blog for his university: "There are a number of causes for sudden cardiac arrest in athletes who are 35 and younger. Sometimes it can just be a normal heart at the wrong place and the wrong time."
Here's what we know about cardiac arrest causes, symptoms, and the risk of it for young athletes:
Causes of cardiac arrest
Cardiac arrest occurs when the heart suddenly stops beating and pumping blood around the body, which prevents oxygen from reaching the brain. This causes a person to fall unconscious and stop breathing, according to the British Heart Foundation.
The causes of cardiac arrest vary and can include heart attacks, heart valve disease, inflammation of the heart (acute myocarditis), congenital heart disease, and inherited heart conditions such as cardiomyopathy.
Other causes include electrocution, drug overdoses, severe hemorrhages, and hypoxia, the BHF said.
Risk of cardiac arrest for young athletes
It's rare for cardiac arrests to occur in people under the age of 30.
A review of US studies published in the British Medical Journal suggests 1 in 40,000 to 1 in 80,000 active athletes develop sudden cardiac arrest each year. The review says the rate appears higher among basketball players, though it's unclear exactly why.
Elderly men and those with underlying heart conditions have the highest risk, according to the National Heart, Lung, and Blood Institute.
Screening rarely detects the conditions that can lead to cardiac arrest in student athletes, a researcher says
According to Higgins, most of the conditions that cause cardiac arrest in young athletes are hereditary, and screening rarely detects early signs.
"For student athletes, screening was normally just medical history questions and a physical exam," Higgins told UT Physicians. "The data shows that history and physicals will only detect 5% to 25% of cases of athletes that have underlying conditions associated with SCA."
He added: "In other words, with traditional screening you're going to miss most of them."
Symptoms of cardiac arrest versus heart attack
While heart attacks can cause cardiac arrests, the two are different: during a cardiac arrest, a person will collapse, fall unconscious, struggle to breath, and/or be unconscious, according to the BHF.
During a heart attack, a person will maintain consciousness and normal breathing. This is because the heart continues pumping despite the blood supply to the heart being cut off (often by a clot in a coronary artery).
Around 90% of cardiac arrests that occur outside of a hospital are fatal, according to the American Heart Association.
However, if paramedics are able to help, a person's chances of survival increase drastically — between 2009 and 2014, 43.8% of athletes who suffered sudden cardiac arrest and were attended to by paramedics went to hospital and lived.