Rebecca Su | Feb. 24, 2015
During a scoreless minor league game in the summer of 1927, Raymond “Pete” Mann of the Macon Peaches was struck in the chest by a pitched baseball. As Mann stepped up to bat at the bottom of the third inning, the ball “took a funny, twisting curve” and caught him right below the heart “with a dull thud.” A doctor was rushed to the scene, but it was too late: the 20-year-old third baseman passed away on the field.
Oddly enough, that unlucky pitch was too slow to fracture a rib, bruise a muscle, or cause any sort of structural damage. But it was fast enough to stop his heart. Our hearts are designed to pump blood in rhythmic, coordinated pulses, and when the baseball struck, Mann’s heart start contracting uncontrollably. His body shut down within minutes.
Among sprained ankles, pulled muscles, and the usual assortment of cuts and bruises, this anomaly, called commotio cordis, is a lesser-known danger in sports. It occurs when a blunt blow to the chest makes the electrical signals in the heart go haywire. The good news is that it’s rare: to trigger cardiac arrest, the impact needs to occur with enough speed, at the right location, and at just the right time between beats. The bad news? It’s usually fatal.
Researchers have documented over 200 cases of commotio cordis in the past 20 years. Most cases have been in children and adolescents, not only because the bones and muscles shielding their hearts are weaker, but also because they’re exposed to more situations — the playground, snowball fights, lacrosse practice — that might involve an accidental blow to the chest. And although it’s been mentioned in papers dating as far back as the mid-1700s, commotio cordis is still a bit of a mystery. Somehow, without ripping through skin or tissue, the mechanical force of an ill-timed ball can throw off the electrical activity our body’s most vital organ.
Starting in a bundle of cells called the sinoatrial node, electrical signals spread through the heart’s four chambers — two atria and two ventricles — to dictate when each should contract. Normally, the pattern is smooth and uninterrupted: in the course of a heartbeat, atria contract and relax, ventricles contract and relax, and the cycle repeats:
(Image courtesy of Wikidoc)
Researchers have proposed that the energy of a blunt strike, landing just as the ventricles are recharging for their next contraction, triggers a premature heartbeat before the previous one fully recovers. This sends the electrical symphony into disarray:
(Image courtesy of N.A. Mark Estes III, MD)
Commotio cordis has drawn more attention in the past decade, along with calls for protective gear and life-saving AEDs at sporting events. But a number of questions remain. For example, researchers are exploring how commotio cordis occurs at the cellular level, as well as whether certain people are more susceptible.
Almost a hundred years after the Macon Peaches played the Asheville Tourists that summer, there are still few definitive answers: science has yet to fully explain the day that Pete Mann struck out.
Rebecca Su is a junior in Silliman College. Contact her at firstname.lastname@example.org.