A D.C.- area pediatric cardiologist said that medical emergencies in student athletes, such as the cardiac arrest LeBron James’ son had during basketball practice rarely happen; they are likely the result of an underlying heart condition.

“I think the one thing for parents to know is that this is rare to have a sudden cardiac arrest in a young person such as Bronny James,” said Dr. Annette Ansong, medical director of Outpatient Cardiology at Children’s National Hospital. “Usually it’s 1 out of 50,000 to 80,000 young athletes that suffer from a sudden cardiac arrest and usually it’s from something underlying such as a structural issue with the heart.”

Bronny James, an incoming freshman at USC, is in stable condition, his family said, after being moved from intensive care.  The 18-year-old son of NBA star James is recovering from a cardiac arrest.

Ansong said that cardiac arrest due to an undiagnosed heart problem can happen without warning, but there can be telltale signs.

“One of the things I ask my young athletes when I see them in the office … ‘Are you having chest pain with activity? Have you ever passed out with exercise or activity?’ So sometimes a provider can be clued in into perhaps doing further work-up based on what the patient is telling them,” Ansong said.

What should parents, particularly parents of student-athletes know?

“First and foremost — knowing your family history, knowing your own personal history … Is there a family history of a sudden cardiac death? Then, the basics … making sure you have a healthy diet, fruits and vegetables, that you’re exercising.”

Ansong recommends that people 18 years old and younger get an hour of exercise a day.

Editor’s note: Bronny James experienced a cardiac arrest. This story has been corrected.