CINCINNATI • Buffalo Bills safety Damar Hamlin suffered a cardiac arrest after making a tackle during Monday night’s game, causing the NFL to suspend a pivotal game against the Cincinnati Bengals that quickly lost significance in the aftermath of a scary scene that unfolded in front of a national television audience.

“Damar Hamlin suffered a cardiac arrest following a hit in our game versus the Bengals. His heartbeat was restored on the field and he was transferred to the UC Medical Center for further testing and treatment,” the Bills said in a statement released Tuesday. “He is currently sedated and listed in critical condition.”

What could have caused Hamlin’s cardiac arrest?

Cardiac specialists say it’s too soon to know what caused Hamlin’s heart to stop, but a rare type of trauma called commotio cordis is among the possible culprits. Commotio cordis occurs when a severe blow to the chest causes the heartbeat to quiver, leading to sudden cardiac arrest.

The condition only happens during a rare set of circumstances: when a sharp hit lands directly over the heart “at the exact wrong location at the exact wrong timing” during the heart’s rhythm cycle, said Dr. Rod Passman, director of the center for arrythmia research at Northwestern University’s Feinberg School of Medicine.

Commotio cordis occurs “probably 20 times a year,’’ and about 60% of those affected survive, said heart rhythm specialist Dr. Mark Link of UT Southwestern Medical Center. The main worry for survivors is brain damage from lack of oxygen when the heart stops pumping blood, Link said. Doctors can help reduce that risk with deep sedation to give the brain a rest, he said.

Dr. Aman Chugh, a University of Michigan cardiology professor, noted that hard-hitting tackles are extremely common in football and that commotio cordis is extremely rare. It could be that Hamlin had a pre-existing heart condition that caused his heart to stop, although that is speculative, Chugh said.

In general, underlying heart disease is the most common cause of sudden cardiac arrest, said Dr. Mariell Jessup, the American Heart Association’s chief medical officer.

“It is not uncommon to find out that very vigorous athletes have undiagnosed cardiac conditions even if they’re young players,” she said.

More than 365,000 people in the U.S. have sudden cardiac arrests in non-hospital settings each year, according to the American Heart Association. Survival depends on quick CPR and shocking the heart back into a normal rhythm, as reportedly happened with Hamlin.

“The teachable moment is learn CPR,’’ Jessup said.