Commotio Cordis: Understanding a Lethal Impact

Welcome to PICU Doc On Call, A Podcast Dedicated to Current and Aspiring Intensivists.

I'm Pradip Kamat coming to you from Children’s Healthcare of Atlanta/Emory University School of Medicine and I'm Rahul Damania, from Cleveland Clinic Children’s Hospital. We are two Pediatric ICU physicians passionate about all things MED-ED in the PICU. PICU Doc on Call focuses on interesting PICU cases & management in the acute care pediatric setting so let’s get into our episode:

Welcome to our Episode about a 14-year-old male who collapsed on the baseball field.

Here’s the case presented by Rahul:

A 14-year-old male athlete was playing in a high school baseball tournament when he was hit in the chest with a pitched ball. The impact caused him to collapse on the field. Bystander CPR was begun given his unresponsiveness and emergency medical services were immediately called. The patient was transported to the hospital. Upon arrival, he was unresponsive and had no pulse. An electrocardiogram (ECG) showed ventricular fibrillation, and advanced cardiac life support was initiated. After several shocks and cardiac compressions, the patient regained a pulse and was transferred to the pediatric intensive care unit for further evaluation and management.

To summarize key elements from this case, this patient has:

• Been struck by a high-velocity object in the chest
• Suffered a cardiac arrest, likely due to an arrhythmia from the blunt chest trauma

The presentation brings up a concern for Commotio Cordis, our topic of discussion today!

We wanted to create this educational episode in light of the recent medical event experienced by the Buffalo Bill’s safety Damar Hamlin. His blunt chest trauma, which led to cardiac arrest, has been postulated to be due to commotio cordis. At the date of this record, we are glad that Damar Hamlin is on the road to recovery.

Absolutely, let’s dive in more into this topic, Let's start with a short multiple-choice question:

The 14-year-old described in our case suffered cardiac arrest after blunt chest trauma. Based on the working diagnosis of comottio cordis, what is the most likely EKG finding which may be seen in this patient?

A. Ventricular fibrillation

B. Ventricular tachycardia

C. Complete heart block

D. Asystole

The correct answer is A. In a study published in JAMA (2002; 287(9):1142-1146) which used data from the US Commotio Cordis registry maintained by the Minneapolis Heart Institute Foundation, reported that the most common arrhythmia out of the 128 confirmed cases, 82 of which had EKGs which could be analyzed was ventricular fibrillation. Three patients had Vtach, 3 had Bradyarrhythmia and 1 had complete heart block. Although 40 patients had asystole, this was unlikely to be the initial rhythm after impact. Interestingly, the majority of these rhythms were recorded at the scene.

Rahul, What is the definition of Commotio Cordis?

Commotio cordis is Latin for "commotion of the heart." It refers to a type of sudden cardiac arrest that occurs when a blunt impact to the chest disrupts the normal electrical activity of the heart and causes ventricular fibrillation. It is a primary arrhythmic event that occurs when the mechanical energy generated by a blow is confined to a small area of the precordium and profoundly alters the electrical stability of the myocardium, resulting in ventricular fibrillation. (NEJM Marron BJ et al. N Engl J Med 2010; 362:917-927)

So Pradip, the case we have involves an athlete, do you mind talking a bit about the demographics and epidemiology of this condition?

Absolutely! As you mentioned, Commotio cordis is Latin for agitation of the heart. Interestingly, it is the 3rd most common cause of sudden death in athletes after hypertrophic cardiomyopathy and congenital coronary-artery anomalies. Commotio cordis shows a predilection for children and adolescents with 26% of victims being younger than 10 years of age, & a minority of patients 25 years of age or older. It has a predilection for males, up to 95% in some reports. Commotio cordis can result from blows to the chest from projectiles (predominantly baseballs, softballs, lacrosse balls, or hockey pucks) or blunt bodily contact with other athletes, especially in children < 15 years of age group.

In summary, here are some patients at risk:

• Male gender
• Young age (typically between 5 and 25 years old)
• Participation in high-impact sports such as baseball, ice hockey, and lacrosse.
• Chest wall size and anatomy

Heart rate and rhythm at the time of impact.

It is important to note that commotio cordis can occur in anyone who sustains a sudden blow to the chest, regardless of age or level of physical fitness.

Rahul, what is the pathophysiology of Commotio Cordis?

The ventricular fibrillation seen after the mechanical energy of the blow is delivered to the chest has been shown to have certain determinants and triggers from animal studies.

Important determinants include:

 1. Location of the blow must be directly over the heart (near the center of the cardiac silhouette);

 2. Timing of the blow, which must occur within a narrow window of 10 to 20 msec on the upstroke of the T wave, just before its peak. That is an electrically vulnerable period, when inhomogeneous dispersion of repolarization is greatest, creating a susceptible myocardial substrate for provoked ventricular fibrillation.

Contributing variables include greater hardness of the projectile, small sphere, direct orientation, and thinner more compliant chest wall (with immature intercostal musculature).

At a molecular level: It is possible that ventricular depolarization induced by a blow to the chest in commotio cordis, has something in common with the pathophysiological mechanisms that give rise to primary arrhythmogenic conditions, such as ion channelopathies. The increased pressure in the ventricle after the impact, causes the cell membranes to stretch and activates ion channels. The candidate ion channels include the ATP-sensitive potassium channel, which contributes to the initiation of ventricular fibrillation in commotio cordis.

The incidence of Commotio Cordis in adults is low even in sports like kickboxing and boxing. A probable explanation for this may be that their mature and fully developed chest cage may be protective.

Pradip, if a child collapses during sports, what should be the approach of the bystanders prior to the arrival of the paramedics?

Early recognition of cardiac arrest is important. Sudden collapse with unresponsiveness, or no breathing or agonal breathing and no pulse, is cardiac arrest unless proven otherwise. 

Immediate high-quality chest compressions should be initiated without interruptions while 911 call is initiated. If an AED is available, then the pads need to be applied to the chest without delay.

Another common scenario is that the child starts to seize after the collapse. This should not be erroneously blamed on a seizure disorder but could be most likely due to brain hypoxia from cardiac arrest.

Rahul, after the initial resuscitation, what are some of the investigations which should be considered?

Early consultation with the cardiologist and electro-physiologist is necessary. Electrocardiography, echocardiography, stress testing, ambulatory ECG monitoring, and cardiac MRI must be considered provided the patient is stable for transport. Electrocardiographic features suggestive of long QT and Brugada syndrome should be pursued if appropriate. Other tests include- CBC, CMP, cardiac enzymes, urine analysis, and even a toxicology screen. Cardiac genetic testing should be considered on a case-by-case basis.

Rahul, what is the management of such a patient in the PICU?

Usual good supportive care with attention to airway, breathing, and circulation should be provided. CVL and arterial lines should be placed and continuous cardiac monitoring initiated. The child may initially require a pressor, like epinephrine, immediately after the arrest for cardiogenic shock. Early extubation when a child is clinically stable should be attempted. Maintenance of judicious fluid balance and correction of electrolytes must be done. Physical and occupational therapy should be initiated early as should the early mobility program to prevent de-conditioning. In the absence of any underlying cardiac disease, there is no indication for any medical or device therapy for survivors of commotio cordis. Such individuals, generally, should have no restrictions for returning to athletic activity.

Check out our episode on post-cardiac arrest care. This two-part episode provides a systems-based breakdown of how to manage the multi-system dysfunction after cardiac arrest.

Pradip, what are some of the community approaches we can use in commotio cordis?

Improved design of sports equipment (using air-filled balls over the dense hardcore balls-although may not be practical as this may change the nature of the game).

Coaching young players to avoid getting hit in the chest by an errant pitch or avoid defending the goal in hockey or lacrosse using the player's chest

Chest protection devices, commercially available protectors, which were originally designed to reduce the likelihood of trauma from blunt bodily injury, do not offer absolute protection from arrhythmia after a blow to the chest. Wearing chest protectors is ineffective in consistently preventing ventricular fibrillation and reducing the risk of sudden death.

AEDs have substantial life-saving capability, and it is appropriate to disseminate them widely at youth sporting events and recreational settings where commotio cordis may occur. Prevention of sudden cardiac death from commotio cordis should be focused on the wider availability of automated external defibrillators and prompt recognition and resuscitation of victims.

Commotio cordis is usually, although not invariably, fatal. The availability of AEDs, public awareness, and early activation of the survival chain has improved survival.

As we close our episode, Rahul, can you summarize some key take-home points?

Commotio cordis is a primary arrhythmic event that occurs when the mechanical energy generated by a blow is confined to a small area of the precordium and profoundly alters the electrical stability of the myocardium, resulting in ventricular fibrillation.

Early recognition of cardiac arrest with prompt initiation of CPR and defibrillation can improve outcomes in patients who suffer severe blunt trauma & commotio cordis.

AEDs should be made available as a public health measure in youth sports or recreational settings! We are pediatricians at heart; thus prevention is key!

This concludes our episode on Commotio Cordis. We hope you found value in our short, case-based podcast. We welcome you to share your feedback, subscribe & place a review on our podcast! Please visit our website picudoconcall.org which showcases our episodes as well as our Doc on Call management cards. PICU Doc on Call is co-hosted by myself Dr. Pradip Kamat and Dr. Rahul Damania. Stay tuned for our next episode! Thank you!

References

Fuhrman & Zimmerman - Textbook of Pediatric Critical Care. Fitzgerald T and Reed C. Pediatric Thoracic trauma. Chapter 119: page 1405

Marron BJ, Estes N. A.M. Commotio Cordis. N Engl J Med 2010; 362:917-927

Estes, N A M; Weinstock, J. My APPROACH to Commotio Cordis. Trends in cardiovascular medicine, 2019, Vol.29(4), p.248

Clinical Profile and Spectrum of Commotio Cordis. Marron BJ et al. JAMA. 2002;287(9):1142-1146. doi:10.1001/jama.287.9.1142