v036p00236 Commotio Cordis
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S udden death following a sharp but seemingly inconsequential blow to the chest is a frightening occur- rence known as “commotio cordis” or “concussion of the heart.” Although commotio cordis is considered rare by some authors, it represents one of the most common mechanisms of sudden death in sport seen in young athletes. 1 Commotio cordis is generally under- stood to mean “instantaneous cardiac arrest produced by non-penetrating chest blows in the absence of heart disease or identifiable morphologic in- jury to the chest wall or heart”. 23 Most cases report accidental death of other- wise healthy children or adolescents after chest impact during recreational or competitive sport or, less commonly, during road traffic accidents. 4–9 Such fatalities receive extensive media coverage, provoke legal debate, and may stimulate research into the public health aspects of this condition—for example, the capacity of protective gear to prevent commotio cordis or the possibility of developing safer sporting equipment. 10 HISTORY The current concept of commotio cordis is often ascribed to a review of 70 cases by Maron et al. 2 Their report portrays commotio cordis as a rare but dangerous condition in which there is usually a poor response to resuscitatory measures. Most of those affected were young (mean age 12 years), male (all but one), and, at the time of accident, engaged in sport (>90%). The event leading to sud- den death was a precordial impact, most commonly by projectiles such as base- balls, softballs, or hockey pucks, probably occurring during an electrically vulner- able phase of the cardiac cycle. 11 Interestingly, the term commotio cordis was in use as early as 1857. 12 13 A review from 1896 shows that the term was applied to various forms (both lethal and non-lethal) of cardiovascular disor- der caused by mechanical impact to the chest (both in the presence and absence of minor cardiac bruising). 14 Commotio cordis underwent a con- ceptual modification at the turn of the century whereby a distinction between non-penetrating precordial impact in the presence (contusion) or absence (com- motion) of cardiac bruising was established. 15 In many ways, the concept of commotio cordis paralleled that of commotio cerebri (brain concussion) for which the issue of structural injury has been controversial since the early 1700s and terminological inexactitude has plagued the medical literature up to the present day. 16 PATHOPHYSIOLOGY The most comprehensive early experi- mental physiological studies of this condi- tion were performed by Georg Schlomka at Bonn University in the early 1930s. 17 On the basis of more than 800 experiments on anaesthetised animals, he identified three factors that determined the induc- tion of arrhythmias by moderate precor- dial impact: type of impact, location of impact, and force of impact. Schlomka disproved the vagal reflex theory and pro- posed the “vascular crisis” concept of mechanically induced coronary vasos- pasms to explain commotio cordis. The risk factors identified by Schlomka in the 1930s are still relevant, whereas the identification of a fourth factor (timing of impact) had to wait for technological advances. Contemporary experimental investigations into com- motio cordis with anaesthetised pigs confirmed the existence of such a vul- nerable period during early ventricular repolarisation and showed the involve- ment of ATP dependent potassium chan- nels in the electrophysiological genesis of this condition. 18–20 When the precordial impacts were delivered within a narrow temporal win- dow between 30 and 15 milliseconds before the peak of the T wave, ventricular fibrillation was reproducibly induced. The vulnerable period of the cardiac cycle amounted to just over 1/100th of a second. Remarkably, ventricular fibrilla- tion was immediate, occurring on the very next heart beat. The arrhythmia was not produced by impacts at any other time during the cardiac cycle, although transient complete heart block was sometimes observed with impacts dur- ing the QRS complex. Occasionally, with impacts delivered just outside the 15 millisecond period of vulnerability, un- sustained polymorphic ventricular tachycardia was seen. 18 19 The observation that transient rhythm disturbances may occur with chest im- pact raises the possibility that there may 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 spontaneously regained consciousness, after being struck on the left side of his chest by a puck during a playoff game. 21 It is possible that other near miss cases have gone undetected because the ar- rhythmias were too brief to cause loss of consciousness. In another part of their study, Link et al 18 examined whether the use of safety baseballs, which are softer than regula- tion balls, could reduce the risk of arrhythmia in the animal model. They found that the risk was proportional to the hardness of the ball. This finding may have implications for the prevention of commotio cordis in young baseball players, as properly designed safety baseballs are feasible for use in recrea- tional baseball and Little League. An- other approach to prevention is the use of chest protectors specifically designed to cushion the precordium. As not all cases will be preventable, it is important to emphasise that rapid cardiopulmon- ary resuscitation, including a precordial “thump” and immediate defibrillation when possible, may be lifesaving. Both early and contemporary research into commotio cordis appears to have been motivated by case reports of sud- den death. It is sobering that a seemingly minor chest impact at an instant when the heart is suspended in diastole can have such devastating consequences. Br J Sports Med 2002;36:236–237 ..................... Author’s affiliations P McCrory, Centre for Sports Medicine Research and Education and the Brain Research Institute, University of Melbourne, Melbourne, Australia Correspondence to: Dr McCrory, PO Box 93, Shoreham, Victoria 3916, Australia; [email protected] REFERENCES 1 McCrory P, Berkovic S, Cordner S. Deaths due to brain injury among footballers in Victoria, from 1968 to 1998. Med J Aust 2000;172:217–20. 2 Maron BJ, Link MS, Wang PJ, et al. Clinical profile of commotio cordis: an under appreciated cause of sudden death in the young during sports and other activities. J Cardiovasc Electrophysiol 1999;10:114–20. 3 Curfman D. Fatal impact: concussion of the heart. N Engl J Med 1998;338:1841–3. 4 Frazer M, Mirchandani H. Commotio cordis, revisited. Am J Forensic Med Pathol 1984;5:249–51. 5 Kaplan JA, Karofsky PS, Volturo GA. Commotio cordis in two amateur ice hockey players despite the use of commercial chest protectors: case reports. J Trauma 1993;34:151–3. 6 Edlich RF, Jr, Mayer NE, Fariss BL, et al. Commotio cordis in a lacrosse goalie. J Emerg Med 1987;5:181–4. 7 Dikman G, Hassan A, Luckstead E. Ventricular fibrillation following baseball injury. Physician and Sports Medicine 1978;6:85–6. Sudden death in sport ................................................................................... Commotio cordis P McCrory ................................................................................... Instantaneous cardiac arrest caused by a blow to the chest depends on the timing of the blow relative to the cardiac cycle 236 LEADERS www.bjsportmed.com
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Commotio Cordis
Transcript of v036p00236 Commotio Cordis
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Sudden death following a sharp butseemingly inconsequential blow tothe chest is a frightening occur-rence known as commotio cordis orconcussion of the heart. Althoughcommotio cordis is considered rare bysome authors, it represents one of themost common mechanisms of suddendeath in sport seen in young athletes.1
Commotio cordis is generally under-stood to mean instantaneous cardiacarrest produced by non-penetratingchest blows in the absence of heartdisease or identifiable morphologic in-jury to the chest wall or heart.2 3 Mostcases report accidental death of other-wise healthy children or adolescentsafter chest impact during recreational orcompetitive sport or, less commonly,during road traffic accidents.49
Such fatalities receive extensive mediacoverage, provoke legal debate, and maystimulate research into the public healthaspects of this conditionfor example,the capacity of protective gear to preventcommotio cordis or the possibility ofdeveloping safer sporting equipment.10
HISTORYThe current concept of commotio cordisis often ascribed to a review of 70 casesby Maron et al.2 Their report portrayscommotio cordis as a rare but dangerouscondition in which there is usually apoor response to resuscitatory measures.Most of those affected were young(mean age 12 years), male (all but one),and, at the time of accident, engaged insport (>90%). The event leading to sud-den death was a precordial impact, mostcommonly by projectiles such as base-balls, softballs, or hockey pucks, probablyoccurring during an electrically vulner-able phase of the cardiac cycle.11
Interestingly, the term commotiocordis was in use as early as 1857.12 13 Areview from 1896 shows that the termwas applied to various forms (both lethaland non-lethal) of cardiovascular disor-der caused by mechanical impact to thechest (both in the presence and absenceof minor cardiac bruising).14
Commotio cordis underwent a con-ceptual modification at the turn of thecentury whereby a distinction betweennon-penetrating precordial impact in thepresence (contusion) or absence (com-motion) of cardiac bruising was
established.15 In many ways, the conceptof commotio cordis paralleled that ofcommotio cerebri (brain concussion) forwhich the issue of structural injury hasbeen controversial since the early 1700sand terminological inexactitude hasplagued the medical literature up to thepresent day.16
PATHOPHYSIOLOGYThe most comprehensive early experi-mental physiological studies of this condi-tion were performed by Georg Schlomkaat Bonn University in the early 1930s.17 Onthe basis of more than 800 experimentson anaesthetised animals, he identifiedthree factors that determined the induc-tion of arrhythmias by moderate precor-dial impact: type of impact, location ofimpact, and force of impact. Schlomkadisproved the vagal reflex theory and pro-posed the vascular crisis concept ofmechanically induced coronary vasos-pasms to explain commotio cordis.
The risk factors identified bySchlomka in the 1930s are still relevant,whereas the identification of a fourthfactor (timing of impact) had to wait fortechnological advances. Contemporaryexperimental investigations into com-motio cordis with anaesthetised pigsconfirmed the existence of such a vul-nerable period during early ventricularrepolarisation and showed the involve-ment of ATP dependent potassium chan-nels in the electrophysiological genesisof this condition.1820
When the precordial impacts weredelivered within a narrow temporal win-dow between 30 and 15 millisecondsbefore the peak of the T wave, ventricularfibrillation was reproducibly induced.The vulnerable period of the cardiaccycle amounted to just over 1/100th of asecond. Remarkably, ventricular fibrilla-tion was immediate, occurring on thevery next heart beat. The arrhythmia wasnot produced by impacts at any othertime during the cardiac cycle, althoughtransient complete heart block wassometimes observed with impacts dur-ing the QRS complex. Occasionally, withimpacts delivered just outside the 15millisecond period of vulnerability, un-sustained polymorphic ventriculartachycardia was seen.18 19
The observation that transient rhythmdisturbances may occur with chest im-pact raises the possibility that there may
be near miss cases of commotio cordis.This may have happened in 1998 to StLouis Blues hockey captain ChrisPronger, when he collapsed briefly, thenspontaneously regained consciousness,after being struck on the left side of hischest by a puck during a playoff game.21It is possible that other near miss caseshave gone undetected because the ar-rhythmias were too brief to cause loss ofconsciousness.
In another part of their study, Link etal18 examined whether the use of safetybaseballs, which are softer than regula-tion balls, could reduce the risk ofarrhythmia in the animal model. Theyfound that the risk was proportional tothe hardness of the ball. This findingmay have implications for the preventionof commotio cordis in young baseballplayers, as properly designed safetybaseballs are feasible for use in recrea-tional baseball and Little League. An-other approach to prevention is the useof chest protectors specifically designedto cushion the precordium. As not allcases will be preventable, it is importantto emphasise that rapid cardiopulmon-ary resuscitation, including a precordialthump and immediate defibrillationwhen possible, may be lifesaving.
Both early and contemporary researchinto commotio cordis appears to havebeen motivated by case reports of sud-den death. It is sobering that a seeminglyminor chest impact at an instant whenthe heart is suspended in diastole canhave such devastating consequences.Br J Sports Med 2002;36:236237
. . . . . . . . . . . . . . . . . . . . .Authors affiliationsP McCrory, Centre for Sports MedicineResearch and Education and the Brain ResearchInstitute, University of Melbourne, Melbourne,Australia
Correspondence to: Dr McCrory, PO Box 93,Shoreham, Victoria 3916, Australia;[email protected]
REFERENCES1 McCrory P, Berkovic S, Cordner S. Deaths
due to brain injury among footballers inVictoria, from 1968 to 1998. Med J Aust2000;172:21720.
2 Maron BJ, Link MS, Wang PJ, et al. Clinicalprofile of commotio cordis: an underappreciated cause of sudden death in theyoung during sports and other activities. JCardiovasc Electrophysiol 1999;10:11420.
3 Curfman D. Fatal impact: concussion of theheart. N Engl J Med 1998;338:18413.
4 Frazer M, Mirchandani H. Commotio cordis,revisited. Am J Forensic Med Pathol1984;5:24951.
5 Kaplan JA, Karofsky PS, Volturo GA.Commotio cordis in two amateur ice hockeyplayers despite the use of commercial chestprotectors: case reports. J Trauma1993;34:1513.
6 Edlich RF, Jr, Mayer NE, Fariss BL, et al.Commotio cordis in a lacrosse goalie. J EmergMed 1987;5:1814.
7 Dikman G, Hassan A, Luckstead E.Ventricular fibrillation following baseballinjury. Physician and Sports Medicine1978;6:856.
Sudden death in sport. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commotio cordisP McCrory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Instantaneous cardiac arrest caused by a blow to the chestdepends on the timing of the blow relative to the cardiac cycle
236 LEADERS
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8 Green E, Simpson L, Kellerman H, et al.Cardiac concussion following softball blow tothe chest. Ann Emerg Med 1980;9:1557.
9 Michalodimitrakis EN, Tsatsakis AM.Vehicular accidents and cardiac concussion.A traumatic connection. Am J Forensic MedPathol 1997;18:2824.
10 Froede RC, Lindsey D, Steinbronn K. Suddenunexpected death from cardiac concussion(commotio cordis) with unusual legalcomplications. J Forensic Sci 1979;24:7526.
11 Maron BJ, Poliac LC, Kaplan JA, et al. Bluntimpact to the chest leading to sudden deathfrom cardiac arrest during sports activities. NEngl J Med 1995;333:33742.
12 Casper J. Practisches handbuch dergerichtlichen Medicine. 1st ed. Berlin: Verlagvon August Hirschwald, 1857.
13 Nesbitt AD, Cooper PJ, Kohl P. Rediscoveringcommotio cordis. Lancet 2001;357:11957.
14 Bernstein R. Uber die durch Contusion undErschutterung entstehenden Krankenheiten desHerzens. Z Klin Med 1896;29:51955.
15 Riedinger F, Kummell H. Die verletzungenund Erkrankungen des Thorax und seinesInhaltes. In: von Bergman E, P vB, eds.Handbuch der praktischen cirurgie. 2nd ed.Stuttgart: Enke, 1903:373456.
16 McCrory P, Berkovic S. Concussion: historicaldevelopment of clinical andpathophysiological concepts andmisconceptions. Neurology 2001;57:22839
17 Schlomka G. Commotio cordis und ihreFolgen. Ergebn Inn Med Kinderheilkd1934;47:191.
18 Link MS, Wang PJ, Pandian NG, et al. Anexperimental model of sudden death due tolow-energy chest-wall impact (commotiocordis). N Engl J Med 1998;338:180511.
19 Link MS, Wang PJ, VanderBrink BA, et al.Selective activation of the K(+)(ATP) channel isa mechanism by which sudden death isproduced by low-energy chest-wall impact(Commotio cordis). Circulation1999;100:41318.
20 Cooper G, Pearce B, Stainer M, et al. Thebiomechanical response of the thoraxtonon-penetrating impact with particularreference to cardiac injuries. J Trauma1982;22:9941008.
21 Luecking D. Pronger relives a scary incident.St Louis Post-Dispatch 1998 May 12;sect C:1.
In 1999 the General Medical Council(GMC) of the United Kingdom agreedthat all doctors must be able to dem-onstrate regularly that they continue tobe fit to practice in their chosen field.1This process is termed revalidation. Doc-tors who complete revalidation will begranted a licence to practice, affordingthem the rights and privileges currentlyassociated with being included on thegeneral register of the GMC.
Each individual doctors revalidationwill be reviewed every five years by twodoctors and a single lay person. This teamwill be drawn from a local revalidationpool of trained people. Revalidation willbe based on the contents of the individualdoctors revalidation portfolio. Each doc-tors portfolio, irrespective of their spe-cialty, will follow a standardised format.The relevant guidelines describing appro-priate standards of practice will be drawnup by the Medical Royal Colleges. Thisimmediately creates a challenge for sportand exercise medicine which does nothave a single parent Medical Royal Col-lege and is not widely recognised as a spe-cialty, although a small number of doctorshave already been placed on the GMCspecialist register.
The Intercollegiate Academic Board ofSport and Exercise Medicine (IABSEM)is responsible to its parent Medical RoyalColleges and Faculties for setting stand-ards in sport and exercise medicine andwould seem to be the appropriate body todraw up relevant guidelines to meetrevalidation standards.
Doctors who are already Members orFellows of a Faculty or Medical RoyalCollege recognised by the Academy ofMedical Royal Colleges will be able toobtain revalidation with the support oftheir parent college. All doctors whopractice sport and exercise medicine oneither a part time or full time basis willhave to meet all the GMC requirements.There are many doctors in the UnitedKingdom who are independent practi-tioners and currently practice sport andexercise medicine without being Mem-bers or Fellows of a Medical RoyalCollege or Faculty. It will be particularlyimportant for this group of sport andexercise medicine practitioners to ensurethat they undergo annual appraisal andare in a secure position to meet therequirements of revalidation.
We here outline the contents of therevalidation portfolio recommended bythe GMC. Establishing a portfolio andpreparing for annual appraisal will be-come an increasingly important aspectof the professional lifestyle of all doctors.
The revalidation folder recommendedby the GMC is divided into foursections.2
SECTION 1: YOUR PERSONALAND REGISTRATION DETAILSThis section will record personal bio-graphical and educational details, in-cluding your current GMC number.
SECTION 2: WHAT YOU DOThis section will describe what you doand where you do it. It must cover allaspects of your medical practice, paid orvoluntary, including private practice,insurance and medicolegal work, teach-ing, research, administration, and man-agement. This section should give a clearoutline of your caseload and case-mix inall aspects of your clinical practice. Itshould include a job description and roleprofile where available.
SECTION 3: INFORMATION ONYOUR PRACTICEThis section will be based on the GMCpublication Good medical practice and willrequire careful preparation and annualreview to ensure its accuracy.3
The portfolio should show good profes-sional standards of clinical care, recordkeepingfor example, contemporaneous,legible, and signed notesand availabil-ity to patients including out of hours andwhen dealing with emergencies.
You will be expected to demonstratethat you are maintaining and developinggood standards of clinical practice byundertaking audits and showing howthe audits have influenced your practice.You will be expected to record adverseclinical events and how they wereresolved. All complaints should also bedocumented and their outcome re-corded.
Communication skills will be assessedby administration of patient surveys, theresults of which will be incorporated inthe portfolio. Sport and exercise medi-cine practitioners involved with a team
Revalidation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Revalidation in sport and exercisemedicineD A D Macleod, M E Batt, S Sheard. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The proposed annual appraisal of practitioners of sport andexercise medicine is outlined
Section 3: Information on yourpractice
Good professional practice Maintaining good clinical practice Relations with patients Working with colleagues Teaching and training Honesty Health
LEADERS 237
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