Commotio cordis is the term given to sudden arrhythmic death due to blunt chest wall trauma. Death is almost instantaneous and the victims are in ventricular fibrillation. Usually there is no structural damage to the heart or thoracic structures. Impacts which occur in the vulnerable phase of ventricular repolarisation just before the peak of the electrocardiographic T wave result in ventricular fibrillation. Rapid rise in ventricular pressure due to the impact possibly causes activation of ion channels by mechano-electric coupling. This causes a ventricular ectopic beat which triggers ventricular fibrillation. Commotio cordis has to be differentiated from contusio cordis in which there is direct myocardial tissue damage and damage to overlying structues of the chest due to a high velocity projectile impact. United States Commotio Cordis Registry instituted in 1996 has collected over 180 cases. Generally commotio cordis is caused by impact by a ball with a dense solid core like base ball. Balls with non-solid core tend to collapse on contact and absorb most of the impact energy so that commotio cordis is quite rare with impact by an air filled soccer ball.

Commotio cordis is more likely to occur in younger individuals, possibly because of greater transmission of the impact energy by a compliant chest wall. Only 28% of cases in the United States Commotio Cordis Registry were over 18 years and the oldest victim was 44 years old. Resuscitation is often difficult in commotio cordis with overall survival of only 15%. An excellent review on the pathophysiology of commotio cordis by Christopher Madias and associates is available, free full text online [Indian Pacing Electrophysiol. J. 2007;7(4):235-245].