On a hot summer afternoon, EMS was dispatched to a community park for a 13-year-old soccer player. Another player had called and reported that the child was unresponsive and not breathing.
On arrival at the scene, an unresponsive child was found in the field. CPR was being attempted by a bystander, but it was very ineffective. EMTs quickly determined that the child was unresponsive, pulseless, and apneic, and had been down for possibly 5-10 minutes. ALS was not available in this small town. The EMTs took over CPR and an AED was quickly applied. After a total of 3 rounds of shocks with no ROSC, the child was transported with ongoing CPR.
On arrival at the ED, the standard ACLS protocol for cardiac arrest was initiated. Initially, the monitor showed ventricular fibrillation, but despite the best treatment, it soon degraded to a pulseless agonal rhythm. Resuscitation attempts were continued for over an hour; no one wanted to give up on this child.
This was a devastating case for all the providers involved. After breaking the bad news to the family, it would have been good to spend some time debriefing with my staff, but no, I was the sole provider in a busy ED. I had to go see the next patient who complained bitterly to me about the wait. Later that evening, I had time to reflect on this case. What could have prevented his death?
It turns out that this boy had a prior episode of near syncope while playing soccer. His parents assumed it was because he got overheated playing soccer and told him he needed to drink more water if he was going to play on a hot day. They even said that another family member, years ago, had died suddenly, working on the farm on a hot summer day.
These are warning flags for a condition called Hypertrophic Cardiomyopathy or HCM, which is fairly rare in females but common in males, especially African American males. It is a genetically inherited condition that leads to abnormal thickening of the heart muscle, especially the interventricular septum, which can obstruct blood flow and cause arrhythmias.
In HCM, the thickened septum and mitral valve leaflet can narrow the outflow tract between the left ventricle and the aorta. During exercise, the heart contracts more forcefully and rapidly – this worsens the narrowing and therefore less blood is ejected, leading to a decreased cardiac output and syncope.
With intense exercise, dehydration, vasodilation, or heat exposure, venous return to the heart is reduced. Lower preload makes the LV cavity even smaller, increasing the degree of obstruction. That’s why many collapses happen during or after exercise in hot weather. The thickened heart muscle has impaired perfusion, especially during high demand.
Exercise increases myocardial oxygen needs but coronary blood flow can’t keep up, resulting in ischemia, chest pain, and arrhythmias. Also, HCM can cause myocardial scarring, resulting in an increased risk of Ventricular Tachycardia or Ventricular Fibrillation.
This condition is one of the reasons children have to have a pre-sport physical to look for risk factors for this condition before joining organized sports, because HCM can result in sudden death with no prior symptoms. If it is suspected, a cardiac ultrasound can be used to confirm the diagnosis or rule it out. Unfortunately, as this was just unorganized recreational play, the child did not have the benefit of a pre-sport physical.
In addition to educating the public about this condition, this case also highlights the importance of teaching the public CPR. This child’s chances of survival may have been better if high quality CPR and an AED had been administered by bystanders before EMS arrival.
References:
Basit H, Alahmadi MH, Rout P, et al. Hypertrophic Cardiomyopathy. [Updated 2024 Jun 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430788/
Marian AJ, Braunwald E. Hypertrophic Cardiomyopathy: Genetics, Pathogenesis, Clinical Manifestations, Diagnosis, and Therapy. Circ Res. 2017 Sep 15;121(7):749-770. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC5654557/
Maron, B.J., Haas, T.S., Ahluwalia, A., Murphy, C.J. and Garberich, R.F., 2016. Demographics and epidemiology of sudden deaths in young competitive athletes: from the United States National Registry. American Journal of Medicine, 129(11), pp.1170–1177. https://doi.org/10.1016/j.amjmed.2016.02.031
