.The Washington Post
January 5, 2023
After Buffalo Bills safety Damar Hamlin collapsed on the field during an NFL game Monday night in Cincinnati, medical experts considered the possibility that his collision with Bengals wide receiver Tee Higgins triggered a condition known as “commotio cordis” that led to cardiac arrest.
Ostensibly, Hamlin’s first-quarter tackle was hardly distinguishable from countless others. But while the cause of Hamlin’s collapse has not been confirmed, an uncommon and unfortunate coalescence beneath the surface may have produced Monday’s outcome, which required Hamlin’s heartbeat to be restored on the field and has left him in critical condition. The high-profile incident put a spotlight on a rare condition that has a history of affecting young athletes in other sports.
Commotio cordis is a phenomenon that occurs after a blunt blow to the chest during a specific moment in the heart’s electrical cycle, resulting in sudden cardiac arrest and the disruption of blood flow to the brain.
“The most common cause of sudden cardiac arrest is coronary disease,” said Mark Link, a professor of internal medicine and director of cardiac electrophysiology at the University of Texas Southwestern Medical Center. “With commotio, the way it causes sudden cardiac arrest is there are a number of variables that have to be perfect. Probably the most important is timing.”
An individual is susceptible to commotio cordis for about 40 milliseconds of the cardiac cycle, contributing to the rarity of the condition. A second factor is the site of the impact, which Link said “has to be directly over the heart, it can’t even be two centimeters away.” Other major variables include the shape, size and force of the striking object, which “can’t be too much, can’t be too little.”
If the heart is struck in a precise 20 to 40-millisecond window of the heart electrical cycle, the impact causes a stretch in myocardial cell membranes, breaking the electric signal’s normal rhythm.
Most of the times, an electric shock from an automated external defibrillator (AED) is required to restore the heart’s normal rhythm.
Because of the specificity of those conditions, Link said such incidents are less common in contact sports such as football, where the size of one’s shoulder pads offers less precision than that of a baseball — the sport in which, at the youth level, commotio cordis is most common. Incidents have occurred in other sports involving hard projectiles, such as hockey, lacrosse and soccer, but also karate and rugby.
There are 15 to 20 known cases of commotio cordis per year, Link said, with the majority occurring in males, peaking in boys around age 15. There’s a drop-off at age 20, which Link partially attributes to a difference in development. He said boys have more compliant, less-developed chest walls (the skin, fat, muscles and bones that shield the heart and lungs), increasing their vulnerability compared with older adolescents and adults.
Link said 70 percent of commotio cordis cases are sports-related, although others occur during everyday life. While some of those instances involve fistfights or playful shadow boxing, others include the case of a 2-year-old girl who was incidentally struck in the chest by the head of her pet dog, or an individual who was struck with a snowball. In another case, a 23-year-old man fatally struck his friend while attempting to remedy the friend’s hiccups.
Within sports, the risk of commotio cordis can be limited, but it can’t be erased.
Link said baseball coaches can teach young athletes not to stand in front of oncoming groundballs: “You’re taught to take a knee and get right in front of a groundball. That’s probably not the best thing to do for a 12-year-old.” He encourages the use of softer, age-appropriate balls, the creation of emergency action plans, and the accessibility of automated external defibrillators (AEDs). He also said he believes it is important to teach high school students CPR.
“It’s a one-hour course and I think it’s an important part of public health that people should know how to do, because CPR is as important as the defibrillators,” he said.
Link has worked with USA Lacrosse and the National Operating Committee on Standards for Athletic Equipment (NOCSAE) to help develop higher standards for chest protectors that can mitigate the dangers of a blow to the chest.
Lacrosse’s national governing body was particularly invested in that research after a string of incidents rattled the sport in the early 2000s.
In March 2000, Louis Acompora, a 14-year old goalie, died from commotio cordis after using his chest to block a routine shot during his first high school game. Cornell captain George Boiardi died in 2004 after a ball struck him in the chest late in the fourth quarter of a game against Binghamton. Five years later, the Sudden Death in Young Athletes Registry had compiled 23 cases of sudden deaths or cardiac arrests in high school and college lacrosse between 1980 and 2008. It concluded that those “catastrophic events were caused disproportionately by commotio cordis.”
Link, who contributed to that research, helped NOCSAE develop chest protectors designed to reduce the impact of a blow to the heart. He serves on USA Lacrosse’s sport science and safety committee.
USA Lacrosse has worked to promote awareness about and standardize rules requiring chest protectors that meet the new standard at the high school and college levels. In 2021, it mandated compliant equipment for boys’ and girls’ goalies, and last year did the same for boys’ and men’s field players.
“Louis Acompora and the Cornell player as well, George Boiardi, their stories were absolutely the catalyst,” Ann Kitt Carpenetti, USA Lacrosse’s vice president of safety & high performance, said of the organization’s recent standards. “You look at those families and their losses, and it could be anyone’s child. It’s very easy for an organization to get distracted on different priorities if you’re growing as rapidly as lacrosse has, but we really have remained focused on keeping athletes safe as we grow the sport, and honoring the memory of those young men by seeing those efforts through.”