A teen gets hit hard to the chest, something that can happen almost any day on a sports field. But a hard hit that a 16-year-old received during a football practice caused his heart to go into an abnormal rhythm called atrial fibrillation for three days and got him written up in a medical journal. It was the first reported case of atrial fibrillation after a hit to the chest.
What happened is a rare circumstance called commotio cordis, a potentially deadly disruption of the rhythm of the heart that is caused by a hard blow to the chest directly over the heart. The hit to the chest has to occur at a very specific time in the cycle of the heartbeat. The heartbeat becomes disrupted and the heart starts to vibrate ("fibrillate") instead of pumping blood in a regular heartbeat.
Usually when commotio cordis occurs, it causes ventricular fibrillation, where the ventricles, the two lower chambers of the heart, vibrate instead of pumping. In this case, the teen was diagnosed with atrial fibrillation, where the atria, the two upper chambers, start to quiver. Atrial fibrillation is not as potentially deadly as ventricular fibrillation, since the heart is able to pump some blood. Symptoms of atrial fibrillation include a rapid or irregular heart rate, and sometimes shortness of breath, especially while laying down.
The teen was taken to an emergency room because of chest pain and palpitations, where he was diagnosed with atrial fibrillation with an abnormal ventricular response. He had no history of heart problems. Three days later, his heartbeat returned to normal on its own, and his heart was healthy and normal a year later.
Ventricular fibrillation due to commotio cordis has caused sudden death to young athletes, but this is extremely rare. Nonfatal cases of ventricular fibrillation or cases that cause atrial fibrillation may be under-reported.