A shocking scene during the Monday night football game between the Buffalo Bills and Cincinnati Bengals. According to the New York Times:

During a Monday Night Football game, Buffalo Bills safety Damar Hamlin tackled Cincinnati Bengals receiver Tee Higgins. After the tackle, Hamlin quickly stood up and took a few steps before collapsing and becoming unconscious. Medical personnel administered CPR and attended to Hamlin for 10 minutes before he was placed on a stretcher and transported to the hospital.

Critical care physician Heidi Abdehaby gave her thoughts on the possible causes:

There are several possible causes for this incident, such as a neurological issue, primary pulmonary issue, or cardiac event. However, the fact that Damar was able to stand up briefly after being tackled makes it less likely that it was a neurological issue. A pulmonary embolism is always a possibility in these circumstances, but given Damar’s age, it is less likely that it was an aortic catastrophe. It is possible that the incident was caused by a “cardiac concussion,” also known as “commotio cordis,” which can occur when a non-penetrating blow to the chest causes an abnormal heartbeat, leading to sudden cardiac death. Quick action, such as high quality CPR and early defibrillation, can be vital in these situations. It is fortunate that trained personnel were able to provide immediate CPR, which gives hope for Damar’s recovery.

Commotio cordis is a frightening and serious condition that can lead to sudden cardiac arrest in young athletes. The term “commotio cordis” comes from Latin and means “agitation of the heart.” It occurs when a blunt impact to the chest disrupts the heart’s normal rhythm. This type of cardiac arrest is most common among young males participating in sports that involve blunt projectiles or physical contact.

The National Commotio Cordis Registry in the United States was established in the mid-1990s to track cases of commotio cordis. To date, the registry has recorded over 200 confirmed cases. These cases are typically characterized by ventricular fibrillation (VF), an abnormal heart rhythm.

There are several risk factors that can increase the likelihood of commotio cordis. These include the timing, location, velocity, and characteristics of the impact, as well as the age of the victim. Impacts that occur during a specific window in the cardiac cycle, over the cardiac silhouette, at higher velocities, and with harder or flatter objects are more likely to cause commotio cordis. Younger people may be more susceptible to this condition because they are more likely to participate in sports involving projectiles, and possibly because the chest walls of younger people are more stiff.

In the past, survival rates for commotio cordis were low, with no survivors among the first 25 patients in the National Commotio Cordis Registry. However, survival rates have improved in recent years, with 58 percent of reported cases surviving between 2006 and 2012. This increase is likely due to improved recognition and activation of emergency services, increased bystander CPR, and earlier use of defibrillation, often by lay bystanders using automated external defibrillators (AEDs).

If commotio cordis is suspected, it is important to follow standard basic and advanced life support protocols, including chest compressions and defibrillation as needed. The use of basic life support and AEDs has contributed to improved survival rates for commotio cordis in both athletes and the general population.

A GoFundMe page was set up to support Hamlin’s community toy drive foundation. Donations currently exceed $3.4 million with over 134,000 contributions.

We wish Damar Hamlin all the best in his recovery.

Kevin Pho is an internal medicine physician and founder, KevinMD.