236 LEADERS Br J Sports Med: first published as 10.1136/bjsm.36.4.236 on 1 August 2002. Downloaded from Sudden death in sport be “near miss” cases of commotio cordis. ................................................................................... This may have happened in 1998 to St Louis Blues hockey captain Chris Pronger, when he collapsed briefly, then Commotio cordis spontaneously regained consciousness, after being struck on the left side of his P McCrory chest by a puck during a playoff game.21 ................................................................................... It is possible that other near miss cases have gone undetected because the ar- Instantaneous cardiac arrest caused by a blow to the chest rhythmias were too brief to cause loss of consciousness. depends on the timing of the blow relative to the cardiac cycle In another part of their study, Link et al18 examined whether the use of safety 15 udden death following a sharp but established. In many ways, the concept baseballs, which are softer than regula- seemingly inconsequential blow to of commotio cordis paralleled that of tion balls, could reduce the risk of Sthe chest is a frightening occur- commotio cerebri (brain concussion) for arrhythmia in the animal model. They rence known as “commotio cordis” or which the issue of structural injury has found that the risk was proportional to “concussion of the heart.” Although been controversial since the early 1700s the hardness of the ball. This finding commotio cordis is considered rare by and terminological inexactitude has may have implications for the prevention some authors, it represents one of the plagued the medical literature up to the 16 of commotio cordis in young baseball most common mechanisms of sudden present day. players, as properly designed safety 1 death in sport seen in young athletes. baseballs are feasible for use in recrea- PATHOPHYSIOLOGY Commotio cordis is generally under- tional baseball and Little League. An- The most comprehensive early experi- stood to mean “instantaneous cardiac other approach to prevention is the use mental physiological studies of this condi- arrest produced by non-penetrating of chest protectors specifically designed tion were performed by Georg Schlomka chest blows in the absence of heart to cushion the precordium. As not all at Bonn University in the early 1930s.17 On disease or identifiable morphologic in- cases will be preventable, it is important 23 the basis of more than 800 experiments jury to the chest wall or heart”. Most to emphasise that rapid cardiopulmon- cases report accidental death of other- on anaesthetised animals, he identified three factors that determined the induc- ary resuscitation, including a precordial wise healthy children or adolescents “thump” and immediate defibrillation after chest impact during recreational or tion of arrhythmias by moderate precor- dial impact: type of impact, location of when possible, may be lifesaving. competitive sport or, less commonly, Both early and contemporary research during road traffic accidents.4–9 impact, and force of impact. Schlomka disproved the vagal reflex theory and pro- into commotio cordis appears to have Such fatalities receive extensive media posed the “vascular crisis” concept of been motivated by case reports of sud- coverage, provoke legal debate, and may mechanically induced coronary vasos- den death. It is sobering that a seemingly stimulate research into the public health pasms to explain commotio cordis. minor chest impact at an instant when aspects of this condition—for example, The risk factors identified by the heart is suspended in diastole can the capacity of protective gear to prevent Schlomka in the 1930s are still relevant, have such devastating consequences. commotio cordis or the possibility of 10 whereas the identification of a fourth Br J Sports Med 2002;36:236–237 http://bjsm.bmj.com/ developing safer sporting equipment. factor (timing of impact) had to wait for technological advances. Contemporary ..................... HISTORY experimental investigations into com- The current concept of commotio cordis Author’s affiliations motio cordis with anaesthetised pigs P McCrory, Centre for Sports Medicine is often ascribed to a review of 70 cases Research and Education and the Brain Research 2 confirmed the existence of such a vul- by Maron et al. Their report portrays nerable period during early ventricular Institute, University of Melbourne, Melbourne, commotio cordis as a rare but dangerous repolarisation and showed the involve- Australia condition in which there is usually a ment of ATP dependent potassium chan- Correspondence to: Dr McCrory, PO Box 93, poor response to resuscitatory measures. nels in the electrophysiological genesis Shoreham, Victoria 3916, Australia; on September 28, 2021 by guest. Protected copyright. Most of those affected were young of this condition.18–20 [email protected] (mean age 12 years), male (all but one), When the precordial impacts were and, at the time of accident, engaged in delivered within a narrow temporal win- REFERENCES sport (>90%). The event leading to sud- 1 McCrory P, Berkovic S, Cordner S. Deaths dow between 30 and 15 milliseconds due to brain injury among footballers in den death was a precordial impact, most before the peak of the T wave, ventricular Victoria, from 1968 to 1998. Med J Aust commonly by projectiles such as base- fibrillation was reproducibly induced. 2000;172:217–20. balls, softballs, or hockey pucks, probably The vulnerable period of the cardiac 2 Maron BJ, Link MS, Wang PJ, et al. Clinical profile of commotio cordis: an under occurring during an electrically vulner- cycle amounted to just over 1/100th of a 11 appreciated cause of sudden death in the able phase of the cardiac cycle. second. 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Pronger relives a scary incident. von August Hirschwald, 1857. 1934;47:1–91. St Louis Post-Dispatch 1998 May 12;sect C:1. Revalidation SECTION 2: WHAT YOU DO ................................................................................... This section will describe what you do and where you do it. It must cover all aspects of your medical practice, paid or Revalidation in sport and exercise voluntary, including private practice, insurance and medicolegal work, teach- medicine ing, research, administration, and man- agement.