What is the diagnosis?

Commotio cordis, which describes sudden ventricular dysrhythmia after chest wall impact leading to cardiac arrest. Most commonly, ventricular fibrillation occurs.

Figure 1. From Adobe Stock 

What is the mechanism of injury?

While the exact etiology is unclear, it is thought that sudden chest wall impact causes stretching of myocardial cells and abnormal ventricular depolarization during the ventricular repolarization phase of the cardiac cycle, specifically during the upstroke of the T wave, similar to what happens during an R-on-T phenomenon. This ultimately leads to dysrhythmia and ventricular fibrillation can occur [5].

• Pearl: Commotio cordis is a rare condition with less than 30 cases reported annually. It generally affects young healthy individuals, with the mean age of 15, and is rare in adults over 20 years old. It has been observed in sports involving projectiles such as baseball, hockey, and lacrosse, as well as non-projectile blows such as in football, rugby and soccer. It has also been observed in recreational settings such as in the playground, backyard and neighborhood [3].

• Pearl: It is important to consider alternate diagnoses when evaluating the patient with sudden cardiac arrest as commotio cordis is a diagnosis of exclusion. The differential diagnosis for cardiac arrest in a young athlete includes [4]:

Table 1. Differential diagnosis for cardiac death in athletes, table created by author

What physical exam findings are expected?

Cardiac arrest. Commotio cordis causes sudden ventricular dysrhythmia requiring resuscitation and early defibrillation. Most commonly, ventricular fibrillation occurs and the athlete will be found unresponsive and pulseless. Other cardiac rhythms that have been observed include ventricular tachycardia, bradyarrhythmias, idioventricular rhythm, complete heart block and asystole[1]. 

The diagnosis of commotio cordis should be suspected in an otherwise healthy athlete who suffers a sudden cardiac arrest after a known trauma to the chest. Patients typically have no underlying structural heart disease and the arrest cannot be attributed to other traumatic injuries (such as tension pneumothorax or cardiac tamponade) [5].

What is the management?

ACLS. Cardiopulmonary resuscitation and early defibrillation for shockable rhythms are the only effective treatment for the management of sudden cardiac arrest. In the event of return of spontaneous circulation, patients should be managed closely in an ICU setting making sure to correct any electrolyte derangements, avoid hypoxia and hypotension, and be placed on advanced cardiac monitoring. Early cardiology consultation can be helpful to evaluate for underlying cardiac pathology that may have led to cardiac arrest.

Figure 2. From Adobe Stock

• Pearl: Most athletes who collapse on the field due to cardiac arrest do so with a shockable rhythm, regardless of commotio cordis or other etiology, therefore, it is imperative that a defibrillator is found and placed as quickly as possible. 

When do you consult a specialist?

Cardiology consultation is recommended once ROSC is achieved to evaluate for potential underlying cardiac abnormalities. This typically includes EKG, echocardiogram, prolonged ambulatory monitoring, and possibly coronary catheterization depending on risk factors. 

What prophylactic measures could have been taken to reduce his risk of injury?

Other than avoiding contact sports, there have been no identifiable prophylactic measures or risk factors associated with developing this condition.

• Pearl: It was thought that chest wall protectors could provide a benefit to high impact sports such as football, hockey and baseball, however there has been no proven benefit to support this. In identified cases of commotio cordis during competitive athletics, approximately one third of athletes were wearing chest protectors.

• Pearl: Currently, the most effective means of improving mortality in these patients is by improved access to CPR training and available AEDs (automated external defibrillators) in athletic environments. Although early resuscitation and defibrillation does not guarantee survival in cases of sudden cardiac arrest, it has the potential to improve survival significantly [3].

What counseling would you provide this patient?

It is recommended that athletes continue to wear chest protectors in sports involving potential for significant chest impact. AEDs should be available in sporting arenas during all athletic competitions. 

The decision to return to play after surviving a sudden cardiac arrest should involve a multidisciplinary team involving cardiology and the patient’s primary care physician. Individuals should undergo cardiac monitoring to determine the risk of future cardiac dysfunction. While this condition is unlikely to recur, athletes and parents should be educated about the potential risks of returning to sport after recovering from cardiac arrest [5].