Commotio Cordis Clinical Presentation

In most reported cases of commotio cordis, sudden death follows a seemingly inconsequential, nonpenetrating blow to the chest. Individuals who have witnessed the events universally believed that the chest trauma was of insufficient force to cause major injury and was out of proportion to the outcome. The person who is struck collapses immediately in most instances. In the remaining cases, the individual has a transient period of consciousness, during which a brief purposeful activity, movement, or behavior (eg, picking up and throwing a ball, crying) is performed before final collapse.

According to data collected by the National Commotio Cordis Registry, at the time of the incident, 50% of persons struck were engaged in organized competitive athletics.^[5] The remainder were involved in normal daily activities (25%) or recreational sports (25%).

Baseball, softball, hockey, and football are the sports most commonly involved. Other associated organized activities included soccer, lacrosse, boxing, and karate. Cases involved with daily activities have included playful boxing, a "remedy" for hiccups, parental discipline, being struck by a snowball, and an accidental kick during cheerleading, among others.

In most instances (58%), the person was struck by a projectile, which was most commonly a pitched, thrown, or batted baseball or softball estimated to be traveling 30-50 mph at most. Other projectiles have included hockey pucks and lacrosse balls. In 42%, chest trauma resulted from bodily contact with another person or a stationary object. Examples of this have included a player's helmet during a football tackle, the heel of a hockey stick, a karate kick, and a body collision.

Survival after a commotio cordis event is still the exception. Although efforts at resuscitation occur frequently, often involving trained bystanders or emergency medical technicians, the onset of cardiopulmonary resuscitation (CPR) is often delayed because observers underestimate the severity of the trauma or believe that the wind has been knocked out of the person. Survival has usually been associated with effective CPR efforts and defibrillation that occur within 1-3 minutes of the collapse. The survival rate was only 3% in cases in which resuscitative efforts were delayed longer than 3 minutes. Although numerous individuals have been resuscitated with the restoration of a perfusing heart rhythm, many of these individuals have experienced irreversible ischemic encephalopathy and ultimately died as a result of the injury.

• Persons with commotio cordis are typically found to be unresponsive, apneic, pulseless, and without an audible heartbeat; many are cyanotic.
• Grand mal seizures have been evident in some persons with commotio cordis.
• Chest wall contusions and localized bruising that correspond to the site of chest impact are noted over the precordium in approximately one third of patients. The ribs and sternum are not structurally injured.

• Clinical and experimental commotio cordis both result from sudden ventricular fibrillation. Precordial impacts result in left ventricular pressure elevation that causes activation of the normally inactive mechanosensitive K⁺_ATP channel which, in turn, leads to inhomogeneity of repolarization and ST segment elevation. Critically timed impacts also produce premature ventricular depolarizations, which sets the stage for ventricular fibrillation in the presence of ischemic-like conditions.^[6]
• Impacts that predominantly occur during a narrow, vulnerable period of repolarization result in ventricular fibrillation. Impacts during other portions of the cardiac cycle are less likely to produce ventricular fibrillation but may result in isolated ST-segment elevation.
• Some observers believe that commotio cordis may include a component of coronary artery vasospasm, myocardial contusion, or both. They believe that this may help explain both the difficulty and the relatively rare success of resuscitative efforts. At present, whether these conditions have a pathophysiologic role in commotio cordis has not been confirmed.