Sudden cardiac arrest is the leading cause of death in the United States, taking the lives of an estimated 400,000 people each year -- more than lung cancer, breast cancer, and AIDS combined. Sudden cardiac arrest, which is not the same as a heart attack, occurs when the electrical system of the heart malfunctions, causing the heart to stop beating.
Sudden cardiac arrest is an indiscriminant killer and can strike anyone - including seemingly healthy young athletes. Between 25 and 33 percent of sudden cardiac arrest fatalities occur during sports activity.
One rare but potentially catastrophic phenomenon in athletes that results in sudden cardiac arrest is commotio cordis. Commotio cordis occurs when a blunt, but often relatively mild, blow to the area of the chest directly over the heart occurs during a precise moment of heart's cycle, leading to sudden cardiac arrest.