Author: Joshua Bucher, MD (Assistant Professor of Emergency Medicine, Rutgers-RWJMS) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Brit Long, MD (@long_brit)

Case

A 43-year-old male arrives in cardiac arrest. According to EMS, he was playing basketball when he suddenly clutched his chest. On EMS arrival, he was ashen, in severe respiratory distress and cardiogenic shock. A 12-lead EKG showed an anterior wall STEMI. On the way to the hospital, he went into cardiac arrest. After 10 minutes of chest compressions, intubation, defibrillations, and epinephrine administration, he is still in ventricular fibrillation.

The young cardiac arrest patient presents a difficult situation for the emergency provider. In general, younger patients are healthier than their geriatric counterparts. There are differences in physiology which may contribute to different prognosis and care.

Andersen et al. evaluated out-of-hospital cardiac arrest patients and found that there was no age in which resuscitation was futile; however, there was a progressive decline in good neurologic outcome after the age range of 45 – 64 years. The best age of survival with good neurologic outcome was 25 – 29 (46%).1

Unfortunately, sudden cardiac death (SCD) is possible at any age. Roberts et al. investigated the incidence of SCD in a Minnesota High School athlete population, and found 4 cardiac arrests out of 1,666,509 athletes, calculated to equal 0.24 deaths/100,000 athlete-years.2 They did not discuss the individual cases, but highlighted that sport-related SCD was uncommon, but present, in the high school athletic population.

Chugh et al. reviewed pre-hospital cardiac arrests and found that the proportion of arrests < the age of 65 in their community was only 25%. 50% of their cases over the age of 35 had the cause of death identified as coronary artery disease, on autopsy, of the non-survivors. Coronary artery disease was observed in 76% of all patients greater than the age of 35. The two patients less than 35 years of age suffered from WPW and congenital aortic disease. Unusually, 74% of the sudden cardiac arrests under the age of 35 had no discernible cause of death identified.3

One area of focus is the setting of exercise induced cardiac arrest. Berdowski et al. collected prospective data on their out of hospital cardiac arrest population. They found that exercise-related cardiac arrest was more likely in a younger patient population, male gender, in public, and with higher rates of bystander CPR and AED utilization. They were also more likely to present with shockable rhythms and demonstrated higher survival. They calculated an incidence of 0.3 exercise related SCD per 100,000 patient years in the less than 35 age group and 2.8 per 100,000 in non-exercise related SCD. Interestingly, all of their survivors of exercise related SCD were neurologically intact, regardless of age. Furthermore, they found that survival was higher in the group of 36 – 50-year-old men compared to less than or equal to 35 and greater than or equal to 51, when the arrest occurred in a public location, had bystander CPR, a public AED was used, shorter response time, and a shockable rhythm on EMS arrival. Overall, survival from exercise related SCD was maintained even when controlling for other variables.4

Marijon et al. also investigated sports and exercise related SCD in the out of hospital environment in France. 95% were male with a mean age of 46. Not surprisingly, bystander CPR and use of an AED were the strongest predictors of survival to discharge. Interestingly, 86.5% of the patients with sports-related SCD were reported to regularly exercise, highlighting that routine exercise does not eliminate the possibility of ACS causing SCD in a healthy population. SCD during team-related sports activities occurred at a significantly younger age than patients performing individual activities such as cycling or running (33 v 51, p <0.0001). There was no correlation between age and survival.5

They also reported on the causes of cardiac arrest. In the young, competitive athlete population, 98% of the causes were related to a cardiac origin. 75% of the patients suffered from acute coronary syndrome. Other causes included hypertrophic cardiomyopathy, congenital cardiac diseases, dilated cardiomyopathy, myocarditis, arrhythmogenic right ventricular dysplasia, commotio cordis, prolonged QT syndrome, mitral valve prolapse, and WPW. There were 4 non cardiac causes identified – epilepsy, cerebral aneurysm rupture, stroke, and ruptured aortic aneurysm. The most common cause was idiopathic.

Marijon et al. investigated a second group of prospective SCD patients in the out of hospital environment in Portland over a 10-year period. They found similar results to the prior study; SCD due to exercise is rare, but an important cause in the younger population. They also found similar causes to the prior study.6

The CASPER study attempted to determine the cause of unexplained cardiac arrest survivors with preserved ejection fraction (with the assumption being that they did not suffer ACS as a cause of the arrest). After adequate testing and follow up, the most common causes were primary electrical disease (65% – Brugada, catecholaminergic ventricular tachycardia, early repolarization, long QT syndrome) and underlying structural issues (35% – ARVD, coronary spasm, dilated cardiomyopathy, myocarditis). The average age of the patients was 48.6; their average age at cardiac arrest was 41.5.7

Farioli et al. investigated SCD rates and causes in firefighters from several available databases. They found that, outside of coronary artery disease, common causes of arrest were hypertrophic cardiomyopathy, dilated cardiomyopathy, left ventricular hypertrophy, myocarditis, and valvular disorders.8

While this is mainly focused on medical causes of death, take care to consider other causes. According to the CDC, unintentional injury is the #1 cause of death in patients aged birth to 44. Suicide is the 2nd most common cause from ages 10 – 34. Homicide is the 3rd most common in ages 15 – 34. Other common causes are malignant neoplasms, and in younger children, congenital anomalies (although this article is focusing on adults). Overall, heart disease is the most common cause of death.9

Case resolution

The patient is defibrillated into sinus tachycardia. He is transferred to the catheterization lab, stented, undergoes therapeutic hypothermia, and walks out of the hospital 5 days later neurologically intact.

Table 1 – Etiologies of young cardiac arrest Coronary artery disease Hypertrophic cardiomyopathy Dilated cardiomyopathy Electrical conduction disorders (Brugada, catecholaminergic ventricular tachycardia, long QT syndrome, ARVD, WPW) Congenital aortic disease Coronary spasm Myocarditis Other

Take Home Points

Younger cardiac arrest patients often have different causes than older patients. Pay strong consideration to congenital abnormalities, conduction disorders, or other cardiac causes outside of coronary artery disease. Younger patients generally have better prognosis than their older counterparts.

References / Further Reading

Andersen LW, Bivens MJ, Giberson T, et al. The relationship between age and outcome in out-of-hospital cardiac arrest patients. Resuscitation. 2015;94:49-54. Roberts WO, Stovitz SD. Incidence of sudden cardiac death in Minnesota high school athletes 1993-2012 screened with a standardized pre-participation evaluation. J Am Coll Cardiol. 2013;62(14):1298-1301. Chugh SS, Jui J, Gunson K, et al. Current burden of sudden cardiac death: multiple source surveillance versus retrospective death certificate-based review in a large U.S. community. J Am Coll Cardiol. 2004;44(6):1268-1275. Berdowski J, de Beus MF, Blom M, et al. Exercise-related out-of-hospital cardiac arrest in the general population: incidence and prognosis. European heart journal. 2013;34(47):3616-3623. Marijon E, Tafflet M, Celermajer DS, et al. Sports-related sudden death in the general population. Circulation. 2011;124(6):672-681. Marijon E, Uy-Evanado A, Reinier K, et al. Sudden cardiac arrest during sports activity in middle age. Circulation. 2015;131(16):1384-1391. Herman AR, Cheung C, Gerull B, et al. Outcome of Apparently Unexplained Cardiac Arrest: Results From Investigation and Follow-Up of the Prospective Cardiac Arrest Survivors With Preserved Ejection Fraction Registry. Circ Arrhythm Electrophysiol. 2016;9(1):e003619. Farioli A, Christophi CA, Quarta CC, Kales SN. Incidence of sudden cardiac death in a young active population. Journal of the American Heart Association. 2015;4(6):e001818. CDC. Ten Leading Causes of Death and Injury. 2016; http://www.cdc.gov/injury/wisqars/leadingcauses.html. Accessed 5/31, 2016.