Commotio Cordis
Let’s talk about commotio cordis, a cardiac phenomenon that puts young athletes at risk for cardiac arrest and death. This can occur with a sudden blunt impact to the chest in the absence of any cardiac damage. Around 10-20 cases are added to the national Commotio Cordis registry annually, and victims are typically adolescents (mean age = 15 years) and are overwhelmingly male. Baseball is the most common sport in which commotio cordis occurs, with pitchers, catchers, and hitters at highest risk. Other common sports include hockey and softball, with a rising incidence in lacrosse due to its increasing popularity.
Currently, the outcomes of cardiopulmonary resuscitation after a commotio cordis event is very similar to that for CPR in other forms of cardiac arrest. An animal model developed at Tufts Medical Center in the 1990s has shed light on the variables critical to induction of commotio cordis. They anesthetized 20-kg male pigs and used a lacrosse or baseball to strike the left chest wall directly over the cardiac silhouette. These animal studies have found that ventricular fibrillation is the most common arrhythmia causing commotio cordis. They have also found that factors like timing, velocity, and shape of the object are critical to it’s initiation.
On an EKG, only impacts within a narrow region of the upslope of the T-wave (40 ms before the peak to the peak) will cause ventricular fibrillation. Also, impact velocities at 40 mph were most likely to to cause v-fib; impacts at 20 mph never induced v-fib; and impacts 50-70 mph showed a reduced occurrence of v-fib and an increased incidence of cardiac rupture or other major trauma. When it comes to shape, spheres with smaller radii were more likely to induce v-fib.
Commotio cordis is another reason why cardiac arrest is the number one medical killer of young athletes, and it is all the more reason to equip youth fields with AEDs and to provide coaches with CPR education.
Source: Mark S. Link, Commotio Cordis: Ventricular Fibrillation Triggered by Chest Impact-Induced Abnormalities in Repolarization, URL: https://www.ahajournals.org/doi/10.1161/circep.111.962712