Mild Blow to Chest in Sports May Cause Heart Failure

A baseball thrown at a modest, Little League speed of 30 mph can cause sudden death from heart failure if it strikes the chest at precisely the wrong moment in the heartbeat cycle, according to a study in today’s New England Journal of Medicine. The study, conducted by throwing balls at anesthetized young pigs, was intended to explain those rare instances in which youngsters with no heart problems dropped dead on the playing field.

The phenomenon is known as commotio cordis, or concussion of the heart. But until now, doctors could only speculate on exactly why a relatively mild blow to the chest can kill. The answer, based on the study: The blow scrambles the heart’s electrical signals at a particularly vulnerable moment. Commotio cordis usually results from being struck by a baseball, but reported cases have also involved softball, karate, football, hockey, even slam dancing. Children are most vulnerable, perhaps because their chest walls are thinner.

Compiled by Times medical writer Thomas H. Maugh II