Lesson

Commotio cordis

Commotio cordis refers to SCA or SCD precipitated by a direct blunt trauma to the precordium during the “vulnerable phase” of cardiac conduction. This is not related to an underlying cardiac condition and occurs in “normal” individuals.

 

History

Commotio cordis occurs as a result of a blunt, non-penetrating blow to the chest (sports projectiles, such as baseballs and hockey pucks or punches). This blow causes spontaneous ventricular fibrillation. It is most common in children and adolescents (mean age 15 years), since these age groups characteristically have compliant chest walls that appear to facilitate the transmission of the energy from the chest blow to the myocardium. These athletes do not have an underlying cardiac disease. Animal experiments attempting to replicate commotio cordis have shown that a blow must hit the chest wall directly over the heart and occur within 15 to 30 milliseconds before the T-wave peak (about 1% of the duration of the cardiac cycle) which represents the vulnerable phase during repolarisation. 19

A blow to the anterior chest wall 15 to 30 milliseconds before the T-wave peak can initiate commotio cordis.

Examination and investigation

As this condition occurs in individuals with structurally normal hearts there are no significant findings.

 

Treatment

Survival rates following commotio cordis are unfortunately very low. As with other causes of SCA the best treatment is immediate defibrillation. The best “treatment” strategy, however, is prevention. The use of softer balls and chest protectors (generally more appropriate in sports other than football) may help prevent this condition from occurring.

 

Whether an athlete should return to sport after experiencing SCA due to commotio cordis is not clear. The athlete would require a comprehensive cardiac work-up (including electrophysiological tests) to exclude underlying cardiac disease. Assuming these were normal, returning to football would be very much an individualised decision. Careful education, including the player, their family and their coaches would be essential. No firm recommendations are given in the literature.