What is Commotio Cordis?

At this point, almost everything is speculative. 

What we do know is that Damar Hamlin collapsed on the field last night due to cardiac arrest. 

He was struck in the chest by a shoulder, got up, and appeared to lose consciousness before awkwardly falling backward onto the ground. 

Based on video and broadcast reports, it's likely Hamlin suffered from commotio cordis. If a blow is delivered directly to the chest and just the right spot, at just the right time in the heartbeat cycle, it can cause a disruption of the electrical signals through the heart, which essentially causes your heart to stop beating in an organized, useful way.

Commotio Cordis Explained

Commotio cordis is very rare in general, 95% of the time occurring in males, and 91% of the time prior to the age of 25, with 15 years old being the average.

It is more common to see in sports with hard projectiles, such as baseball or hockey. There is no known specific force threshold that has to be reached in order to cause commotio cordis, but higher forces seem to make it more likely. 

It is thought that many instances of car accident fatalities are due to this. Since 2006, 58% of cases have survived, with the biggest factor in survival being time to CPR. 

Dr. David Chao was correct when he said that outside of a hospital, an NFL field during a game is probably the best place for this to happen in terms of a rapid, robust medical response and chances for a good outcome.

He was given CPR, reportedly including chest compressions on the field, for 8 to 10 minutes. 

He was transported to the local hospital and admitted to the ICU. He is intubated and on a ventilator, meaning there is a tube down his throat connected to a breathing machine. He is listed as in critical condition.

The wording gets a little bit confusing here, because anybody on a ventilator will be listed as in critical condition. 

However, it sounds as though his vital signs are stable, which is a great sign. For 24 hours after CPR, it is common to undergo targeted temperature management, a cooling of the body in order to protect vital organs from ling term damage, and a patient cannot be awake for that.

Commotio Cordis in Sports

In the 90s, there was a hockey player named Chris Pronger who this happened to. He collapsed on the ice, he was also resuscitated, and he went on to play that season and had a long career, and he was actually elected to the hockey Hall of Fame.

There is precedent that a player can continue playing after experiencing commotio cordis, but it is much too early to speculate about Hamlin's future.

All NFL players undergo quite intensive evaluations at the beginning of their careers, in the pre-season, and in-season. You may have heard of a player needing to “pass a physical” prior to a trade being official. The primary purpose of these exams is actually to rule out any cardiac abnormalities or risk factors (along with head injuries). Evaluating joints, muscles, and other previous injuries is secondary. Players have labs done, cardiac exams, tests, and/or imaging at least yearly in order to minimize these sort of catastrophic events. Even given this vigilance, football is a collision sport with inherent risk, and things like this can happen. It is important to remember the risk these players take each time they take the field.