Sudden Cardiac Arrest: Commotio Cordis

Ovid: 5-Minute Sports Medicine Consult, The

Sudden Cardiac Arrest: Commotio Cordis
Kevin E. Elder
Early resuscitation with cardiopulmonary resuscitation (CPR)/defibrillation improves survival; however, even with early resuscitation within 2–3 min survival is only 25%.
Commotio cordis (CC), Latin for “disturbance of the heart,” is blunt, nonpenetrating trauma to the precordium, which results in an irregular heart rhythm such as ventricular tachycardia or ventricular fibrillation (VF). This is a rare event, but must be considered secondary to its lethal nature.
  • This condition occurs primarily in young males, with the highest incidence in sports such as baseball and hockey; however, it can be seen in sports such as softball, lacrosse, and soccer as well. It may occur in any sport with male or female participants whereby a blow, via contact with another player, or via the ball/puck exerts a sudden impact to the precordial region.
  • Commotio cordis was 1st described in 1763, and at least 190 cases have been documented in the U.S. alone.
  • It is the 2nd most common cause of sudden cardiac death in athletes younger than 35.
  • Greater recognition of this condition has led to improved reporting of it.
  • The prevalence is higher in competitive sports, with nearly half of the cases occurring during competitive sports. The mean age is 15.6 ± 6.5 yrs, with young males 4–18 at greatest risk (1).
  • Youth baseball accounts for most of the cases.
  • 60% of reported CC events involve sports.
  • >190 cases of CC in the U.S. Only 5 reported prior to 1983; thought to be related to lack of recognition/underreporting.
  • 20% of sudden cardiac death (SCD) cases (77 of 387)
  • Occurs mostly in competitive sports, with highest incidence in youth baseball (1)
  • 25% of CC cases in youth baseball were from a pitch traveling 30–50 mph.
  • CC is the 2nd most common cause of SCD in young athletes, 2nd only to hypertrophic cardiomyopathy.
  • There has been an increase in reported cases of this condition, with only 5 cases reported prior to 1983; however, there are more than 180 cases reported in the CC registry today (2).
  • Decreased prevalence of CC prior to 1983 felt to be related to lack of recognition/underreporting.
  • 47% of cases occur during competitive sports, with total of 60% occurring with all sports participation.
Risk Factors
  • Participation in competitive sports known to have a greater risk of CC.
  • Harder projectiles used in certain sports are more likely to cause CC, with use of standard baseballs and pitches with speeds between 30 and 50 mph carrying the highest incidence of developing the insult.
  • Velocities above and below this range did not seem to carry the same risk.
  • Use of protective equipment has not been demonstrated to offer adequate protection from CC.
  • No specific genetics have been attributed to the condition. Increased chest wall pliability in the most vulnerable age group of young males may play a role.
  • It is unclear why there is a male predilection for this condition, aside from increased relative participation in competitive youth baseball relative to females.
General Prevention
  • The U.S. Consumer Product Safety Commission recommends use of softer “safety baseballs” to reduce the risk of soft tissue trauma (3). These “safety baseballs” reduced the risk of onset of VF after precordial impact in a swine model study, and there is a linear correlation between CC events and the relative hardness of a baseball (4)[B]. However, safety baseballs have not been proven to eliminate risk of CC.
  • Doerer et al. and Weinstock et al. have demonstrated that chest protectors (commonly worn by catchers) in baseball did not prove to be effective in eliminating cases of CC (5). Only 13% of victims who were wearing chest protectors survived a CC event. It is theorized that malpositioning of equipment (when the athlete moves or raises his hands) may contribute to this failure. A swine model by Link et al. revealed that commercially available chest protectors did not prevent CC (6).
  • Changes in coaching techniques to eliminate chest blocking are theorized to potentially reduce CC events.
  • Public health measures, such as parents/coaches learning CPR, and the increased availability and use of automated external defibrillator (AED) may provide the biggest impact on improving CC outcomes, but cannot necessarily prevent onset of CC due to the pathophysiology of condition.
  • Impact to the precordium during the vulnerable period of the repolarization upslope of the T-wave (10–30 ms before the T-wave peak) may lead to VF. VF is the most common initial rhythm in CC.
  • A study by Link et al. demonstrated that low energy impact, directly over the heart, specifically over the center of the left ventricle (LV), carries the highest risk. Blows at noncardiac sites in this study did not generate VF (7).
  • The role of projectile speed and projectile hardness has been discussed. The ideal projectile speed and hardness create an ideal energy transfer that potentiates this often-lethal condition.
  • Causative theories on predisposition to VF/CC include rapid rises in LV pressures to forces between 250 and 450 mm Hg that may potentiate the associated arrhythmia. Stretch channels may be activated due to associated myocardial stretch with impact, and potassium adenosine triphosphate channel activation has been implicated (8).
  • Critical mass of projectile leading to higher velocity impacts tends to lead to myocardial damage as opposed to myocardial activation.
  • Sympathetic activation occurring during sports participation may increase the likelihood of CC, but this has not been substantiated in research studies.
Commonly Associated Conditions
  • Contusio cordis
  • Myocardial contusion with tissue damage
  • Rule out other causes of SCD causing arrhythmia such as hypertrophic cardiomyopathy (HCM).
Witnessed trauma to the precordium followed by collapse should elicit suspicion of CC, especially when occurring during highest-risk sports in young athletes.
Physical Exam
Physical exam is best aided by use of an AED to determine that the athlete has developed the potentially lethal arrhythmia associated with CC. A more thorough physical exam in the acute setting is impractical. Any physical exam should be focused on institution of advanced cardiac life support (ACLS) protocols, with use of AED as soon as possible.
Diagnostic Tests & Interpretation
  • There are no specific labs/imaging tests to aid in diagnosis.
  • CC is a diagnosis made based on witnessed precordial blow and confirmed by AED recognition of subsequent arrhythmia.
Pathological Findings
Autopsy is notable for absence of any significant cardiac or thoracic injury.
Differential Diagnosis
  • HCM
  • Long QT syndrome
  • Wolff-Parkinson-White syndrome
  • Arrhythmogenic right ventricle dysplasia
  • Brugada syndrome
  • Dilated cardiomyopathy
  • Marfan syndrome
  • Aortic valve stenosis
  • Mitral valve prolapse
  • Coronary artery disease
  • Myositis
  • Asthma
  • Heat stroke
  • Drug abuse (1)[C]


Ongoing Care
Follow-Up Recommendations
Patient Monitoring
  • All patients should be admitted to the hospital for observation and monitoring after a CC event to undergo complete cardiac evaluation (11)[C].
  • Patients should be followed after discharge to assess for potential cardiac or neurologic deficit.
Patient Education
  • An individual athlete's susceptibility to CC should be considered in any return to play decisions regarding contact sports.
  • Decisions are made on a case-by-case basis, with consideration given to residual cardiac deficit, neurologic deficit, or other morbidity. Cardiology consultation should be involved in these decisions (4)[C].
  • Maron et al. demonstrated that 71% of CC survivors achieved complete physical recovery (10).
  • CC is a condition that carries a grave prognosis. Despite use of ACLS protocols, the condition is often lethal. Immediate recognition of condition and use of AED to abolish cardiac arrhythmia may allow improved survival and decreased subsequent morbidity.
  • As the availability and use of AEDs during athletic participation occurs, their effectiveness may be further measured in future studies.
861.01 Contusion of heart without mention of open wound into thorax

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