Commotio cordis – a chest blow to athletes that can be fatal

When I and my family went mountain walking last weekend, I observed a young man donning on protective gear as he gear as he prepared for his downhill bicycle ride down from the 1400-meter mountain we were on. Helmet, elbow pads, knee pads – and pads around the torso. I’m not a mountain cyclist myself so I’d only imagine the dangers of such a sport. And I wondered – can his protective gear protect him if he falls?

Commotion of the heart

A paper presented at the 2006 American Heart Association’s Scientific Sessions reported that commercially available gear intended to protect athlete’s chests from a hard blow may not be enough to prevent serious injury leading to sudden death. They call it commotio cordis (“commotion of the heart” in Latin), “a blunt, non-penetrating blow to the chest that triggers an irregular heartbeat called ventricular fibrillation.”

If you like to watch contact sports like American football and rugby, you can imagine how easy it is to get such a blow on the chest through head butts, elbowing and kicks. But other sports like hockey, baseball, and football can be hazardous as well. Imagine being hit by a hockey stick, a bat, or a high-speed ball on the chest. No wonder that hockey goalkeepers and baseball catchers wear masks and chest protection gear.

What happens during commotio cordis?

The blow can lead to ventricular fibrillation,

a condition in which the heart’s electrical activity becomes disordered. The heart’s lower (pumping) chambers contract in a rapid, unsynchronized way and little or no blood is pumped from the heart. Collapse and sudden death follows unless medical help is provided immediately.

Not all chest blows result in commotion cordis. It all depends on the timing, the authors said. A blow of the same force can be benign or can be fatal depending on the heart cycle at the time of the impact – a split second time difference really.

In an experimental model of commotio cordis developed at the New England Medical Center and Tufts University School of Medicine in Boston, ventricular fibrillation could be produced by a baseball moving 30 mph, but only if impact occurs directly over the heart during a 20 millisecond window when the lower heart chambers (ventricles) relax electrically, which may explain why events are rare, although tragic.

Who gets commotio cordis?

The authors established the National Commotio Cordis Registry at the Minneapolis Heart Institute Foundation in 1995 to record and study cases of commotion cordis.

The registry tracked 182 cases since 1995, with the following statistics:

• 47% occurred during training or competition in organized sports
• 39% of fatal events occurred despite the presence of potentially protective equipment.
• 53% of cases occurred during recreational sports or in normal daily activities.

Of the athletes who suffered from commotio cordis,

• 14 were hockey players, 2 of whom were goalies
• 10 American football players
• 6 lacrosse players, 3 of whom were goalies
• 3 baseball players, all catchers

Average age of athletes affected was 15 years.

While most of the players wore protective gear, 23 deaths occurred among those whose padding did not properly cover the chest, thus the blows and projectiles missed the protective barrier and hit the chest directly. However, 10 players died despite projectiles hitting the chest padding, indicating that the protective gear were not strong enough to suppress the blow.

What next?

To be fair to the manufacturers, these protective gear were not designed for protection from commotio cordis, basically because the occurrence is rare and very little research has been done on the topic. The next step is to move on with research on product development to look for materials and design that can provide maximal protection. As mom of 2 boys who show keen interest in all kinds of sports, this is something I have to to keep an eye on.

Photo credit: morguefile