DENVER (KDVR) — The Buffalo Bills say Damar Hamlin suffered a cardiac arrest during the Monday night game against the Cincinnati Bengals.

The NFL star collapsed during the game and was taken to an area hospital where he was in critical condition Tuesday.

Now local cardiologists are explaining what can cause something like that to happen.

Dr. Brian Stauffer is the chief of cardiology at Denver Health. He says while cardiac arrest can be caused by congenital heart disease or genetic abnormalities, it can also be caused by something called commotio cordis.

“He took a pretty sharp hit to the chest,” Stauffer said.

In rare cases, a person can be hit in a specific area of the chest during a specific part of the electrical cycle of the heart, and that causes arrhythmia.

 “It has to be at a specific instant during that normal cardiac cycle where the electrical system is disrupted and then the heart goes into this abnormal electrical cycle,” Stauffer said.

Doctors say commotio cordis tends to happen in young athletes with less developed chest walls who are hit by a projectile like a baseball or a hockey puck.

“It’s a very rare phenomenon and obviously since the 1990s it’s been reported roughly 10 to 30 cases in a year,” Dr. Vijay Subbarao, a cardiologist at Denver Heart at Rose Medical Center said.

Subbarao says awareness is key. Immediate CPR and defibrillation with an automated external defibrillator are critical.

“Some of these situations happen so fast they are difficult to avoid,” he said. “This is obviously not a death sentence if you’ve got people that are there that can take care of you right away.”

As of Tuesday evening, Hamlin remained in critical condition in the ICU, the Buffalo Bills said in a tweet.