"An unlikely conspiracy of a number of variables can conspire to cause sudden death from a hit in the chest," says Barry J. Maron, MD, director of the Hypertrophic Cardiomyopathy Center at the Minneapolis Heart Institute.
Maron established the first national registry to track the condition, known as commotio cordis, in 1995. Since then, he has recorded 85 cases in which young athletes were killed by a chest blow during organized sporting events. In 33 cases, the child was wearing protective gear.
Those numbers underestimate the scope of the problem, he tells WebMD. "We could only collect data on what we knew about -- if the death was published in a newspaper and could be found using a search engine, for example. Or if we heard about it by word of mouth."
Speaking here at the annual meeting of the American Heart Association (AHA), Maron says that fatal blows are most common among children aged 13 to 15 who are playing baseball, softball, or hockey.
Before collapsing and dying, "these were healthy kids with no genetic predisposition to early heart problems," he says.
Conspiracy of Timing and Location
He blames the deaths on an unlucky alliance of the location and timing of the hit. "The blow has to be directly to the heart -- that is, the left chest area. And it has to be timed exquisitely to a vulnerable period of the heart cycle when there is electrical relaxation of the lower chambers, a period that lasts only 20 milliseconds," Maron says.
The result is ventricular fibrillation, when the heart's electrical activity goes out of whack. The electrical storm makes the heart quiver, and little or no blood is pumped out to the rest of the body. The child collapses and dies if a defibrillator is not immediately used to shock the heart back to normal.
Maron adds that the velocity of the ball or puck when it hits the chest doesn't appear to matter. "Some were very innocent blows," he says.
Difficulty of Protecting the Heart
In the study, 23 of the children who died were wearing gear that did not cover the chest. In the other 10 cases, the blow directly struck the chest protector, and the kids still died.
"They were wearing standard commercially available chest gear, made of polymer foam, covered by fabric or hard shell," Maron says. "None have been proven to absorb the energy from a blow to the heart."
He says a few new products are in development but they're a long way from being ready for use. "They have to be thick but practical, wearable but effective, and relatively inexpensive. So it may not be so easy," he says.
Advice for Parents
So what should parents do in the meantime?
Richard Stein, MD, an AHA spokesman and director of preventive cardiology at Beth Israel Medical Center in New York City, says parents should make sure their child's school or team has a defibrillator on hand -- along with coaches or teachers who are trained to use it.
"You really only have three minutes to act," he tells WebMD. "Make sure they are trained to respond to a downed athlete right away."
SOURCES: American Heart Association's Scientific Sessions 2006, Chicago, Nov. 12-15, 2006. Barry J. Maron, MD, director, Hypertrophic Cardiomyopathy Center, Minneapolis Heart Institute. Richard Stein, MD, spokesman, American Heart Association; director, preventive cardiology, Beth Israel Medical Center, New York City.
By Charlene Laino
Reviewed by Louise Chang