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Damar Hamlin suffered commotio cordis, causing his cardiac arrest. What is it?

Buffalo Bills safety Damar Hamlin confirmed his cardiac arrest during an NFL game in January was due to a rare heart condition called commotio cordis.
/ Source: TODAY

Buffalo Bills safety Damar Hamlin confirmed that a condition called commotio cordis caused his cardiac arrest when he collapsed while making a tackle during an NFL game on Jan. 2. He was given CPR, and his heartbeat was restored on the field with a defibrillator, and he was rushed to University of Cincinnati Medical Center.

During a press conference on April 18, less than four months after the incident, Hamlin announced that he had been cleared to return to playing football after meeting with three medical specialists last week, who all said he could return without any increased risk for injury, the Associated Press reported.

“This event was life-changing, but it’s not the end of my story,” Hamlin said. “So I’m here to announce that I plan on making a comeback to the NFL.”

Indianapolis Colts v Buffalo Bills
Damar Hamlin of the Buffalo Bills on the sideline during a preseason game against the Indianapolis Colts on Aug. 13, 2022, in Orchard Park, New York. Timothy T Ludwig / Getty Images

Bills general manager Brandon Beane added: “They’re all in lockstep of what this was, and that he is cleared to resume full activities, just like anyone else who was coming back from an injury. He’s in a great headspace to come back and make his return.”

The doctors have called the 25-year-old's recovery nothing short of remarkable. Three days after his cardiac arrest, his medical team said he was showing "remarkable improvement" and appeared neurologically intact. At that time, he had his breathing tube removed and was able to talk with family at teammates. A week after the incident, he was transferred from the hospital in Ohio to another hospital in Buffalo, New York. Two days later, he was cleared to leave the hospital and go home.

In February, he attended the Super Bowl alongside the medical team that care for him.

It’s unclear exactly how much time passed before Hamlin’s heartbeat was restored. After collapsing, he received CPR on the field for several minutes, according to the ESPN commentators calling the game, as players and fans watched in shock.

In footage of the tackle, Hamlin can be seen taking a hard hit to his chest. After getting up and taking a few steps, his body goes limp, and he collapses onto his back, due to commotio cordis.

What is commotio cordis?

Commotio cordis is Latin for "agitation of the heart," and it occurs when a person gets hit in the chest with a certain amount of force at a very specific time in the heart cycle, when the electricity is flowing from one side of the heart to the other. "Then that can trigger cardiac arrest. ... It can be a lethal condition," NBC New senior medical correspondent Dr. John Torres said in a TODAY segment in January.

Hamlin had no existing health issues or heart problems, according to his uncle.

The condition is "incredibly rare" a "diagnosis of exclusion," explained Dr. William Knight IV, director of the Emergency Medicine MLP Program at University of Cincinnati Health, at a Jan. 5 press conference — meaning that Hamlin's doctors had "to rule out many other more common or more deadly or more fixable type conditions" before settling on commotio cordis.

According to Dr. Khalid Aljabri, a Boston-based cardiologist, commotio cordis is not associated with pre-existing heart damage or the COVID vaccine.

Since 1995, there have only been 200 documented cases of commotio cordis in the United States. It's mostly seen in athletes between the ages of 8 and 18 partaking in sports with projectiles, according to the University of Connecticut’s Korey Stringer Institute, dedicated to preventing sudden death in sports.

"In the last couple of decades, we have recognized that you can have this non-penetrating blunt trauma to the chest. It happens in baseball (and) in hockey with hockey pucks," NBC News medical contributor Dr. Natalie Azar told TODAY in a segment aired Jan. 3.

Commotio cordis is a leading cause of death among young athletes, and Hamlin wants to raise awareness of the condition and increase CPR training and access to defibrillators.

Can commotio cordis happen from a tackle?

"So how could this have happened (during) what looked like ... a very typical tackle?" Azar wondered. If the hit to the chest happens at the exact right time in the cardiac cycle, she continued, the impact can trigger a life-threatening arrhythmia (or abnormal heart beat) called ventricular fibrillation. Life-threatening arrhythmias cause most sudden cardiac arrests, according to Cleveland Clinic.

Even a low impact projectile or a strike to the middle of the chest with a hand (during martial arts, for example) can be enough to cause the heart to enter an arrhythmia, per the Korey Stringer Institute.

In addition to the right timing, the impact has to happen in the right location, according to experts.

“Hits like this happen 200, 300 times every weekend in the NFL. ... There was nothing extraordinary or particularly different about the hit. It’s probably just where he got hit in the chest," Peter King, NBC Sports columnist, told TODAY in a segment aired Jan. 3.

Can you survive commotio cordis?

When this condition does occur, “you want to start CPR within two minutes," Torres said. "They had defibrillators on hand, which I’m sure they used during CPR to try and get (Hamlin) resuscitated.”

Knight and Pritts confirmed that had CPR and defibrillation been delayed by minutes or even seconds, Hamlin's prognosis likely would've been much bleaker.

According to a 2009 literature review of commotio cordis published in Sports Health, resuscitation within 3 minutes resulted in a survival rate of 25%, and that rate dropped to 3% when resuscitation is delayed beyond 3 minutes.

“Cardiac arrest is one of the most time-sensitive diseases in all of medicine. If CPR is not started right away, the chance of survival falls 10% to 15% per minute without CPR,” Dr. Benjamin Abella, director of the Center for Resuscitation Science at the University of Pennsylvania, tells

“It is a very horrifying, rare thing to witness a cardiac arrest live. ... That is a real trauma,” he adds.

What is recovery like from commotio cordis?

Even if CPR is successful after cardiac arrest, patients still have a challenging road ahead, Abella says.

“When you look across the United States, survival from the moment cardiac arrest strikes to leaving the hospital is less than 20%,” says Abella. This also depends on when the CPR was started, how well CPR was performed and the availability of automated external defibrillators (AEDs), he adds.

“Brain injury is a common problem after cardiac arrest to varying extents in different people,” Abella says.

"There are some well-known cases of athletes who made full recoveries after cardiac arrest — most notably, Fabrice Muamba in 2012 and Christian Eriksen (in 2021),” Abella continued, adding that both players also had prolonged CPR after their cardiac arrests.

And another professional athlete has even returned to playing just days after suffering commotio cordis mid-game. Hockey player Chris Pronger collapsed on the ice during the 1998 NHL finals after he took a slapshot to the chest. He resumed playing again two days later and stayed in the NHL for 13 more seasons.

At the April 18 press conference, Hamlin addressed critics of his to return to football after his cardiac arrest.

“Some people might say that coming back to play might not be the best option, but that’s their opinion,” he said. “And like I said, I’ve been beating statistics my whole life. So I like my chances here.”