Commotio cordis

Commotio cordis
Human adult thorax, showing the outline of the heart in red. The sensitive zone for mechanical induction of heart rhythm disturbances lies between the second and the fourth ribs, to the left of the sternum.
Specialty	Cardiology
Complications	Ventricular fibrillation, quickly followed by cardiac arrest and (if not treated) death
Usual onset	Within seconds after impact
Causes	Sufficient blow to the precordium between 10 and 40 milliseconds before the peak of the T wave portion of normal cardiac rhythm
Risk factors	Coronary ischemia can reduce amount of impact energy required to trigger
Treatment	CPR, defibrillation
Prognosis	Survival rate drops to <5% if not resuscitated within 3 minutes
Frequency	Extremely rare

Commotio cordis (Latin, "agitation or disruption of the heart") is a rare disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart (the precordial region) at a critical instant during the cycle of a heartbeat.^[1] The condition is 97% fatal if not treated within three minutes.^[2] This sudden rise in intracavitary pressure leads to disruption of normal heart electrical activity, followed instantly by ventricular fibrillation, complete disorganization of the heart's pumping function, and cardiac arrest. It is not caused by mechanical damage to the heart muscle or surrounding organs and is not the result of heart disease.

Its incidence in the United States is fewer than 20 cases per year, often occurring in boys participating in sports, most commonly in baseball when a ball strikes a player in the chest.

Commotio cordis can occur only upon impact within a narrow window of about 40 milliseconds in the cardiac electrical cycle, explaining why it is so rare.^[1]

If cardiopulmonary resuscitation (CPR) combined with use of an on-site automated external defibrillator is employed within three minutes of the impact, survival from commotio cordis can be as high as 58 percent.^[3]