Summary
Sudden cardiac arrest (SCA) and sudden cardiac death (SCD) in children and young adults are rare events most commonly caused by undiagnosed congenital or inherited cardiac conditions, including cardiomyopathies (e.g., hypertrophic cardiomyopathy), cardiac channelopathies (e.g., long QT syndrome), and congenital anomalies (e.g., anomalous coronary arteries). The risk of these events is higher in young athletes, male individuals, and individuals of African descent. Routine screening is recommended in all children, regardless of participation in sports. Any child or young adult with suspected increased risk of SCA should have a diagnostic evaluation to assess for cardiac conditions that can cause SCA. Strategies for both primary prevention and prevention of recurrent SCA include management of underlying cardiac conditions, activity modifications, and implantable cardioverter defibrillator placement. Institutional preparedness and rapid access to automated external defibrillators (AEDs) are crucial to improving survival and preventing SCA from progressing to SCD.
Definitions
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Sudden cardiac arrest (SCA) [1]
- The abrupt cessation of effective cardiac mechanical activity, which results in the sudden loss of cardiac output, systemic perfusion, and consciousness
- Fatal without treatment, but immediate initiation of resuscitative measures may restore circulation
- Sudden cardiac death (SCD): unexpected death from cardiac arrest that occurs within 1 hour of symptom onset or within 24 hours in asymptomatic individuals [1]
Epidemiology
Etiology
SCA and SCD are typically caused by congenital or inherited cardiac conditions. [4]
- Cardiomyopathies
- Cardiac channelopathies
- Accessory pathway-mediated arrhythmias: Wolff-Parkinson-White syndrome (WPW) [2]
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Congenital anomalies
- Anomalous coronary arteries, e.g.:
- Congenital heart disease (repaired or unrepaired)
- Other cardiac conditions [2]
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Substance-related and metabolic causes
- Drugs (e.g., performance-enhancing drugs, cocaine)
- Toxins (e.g., ethanol)
- Electrolyte abnormalities
Screening
For patients with positive screening, see "Approach to children and young adults at increased risk of SCA." [4]
Indications [4][5]
- Before sports participation in children and young adults
- All children at well-child visits at one of the following intervals: [4][5]
- At least every 3 years
- Start of middle or junior high school and start of high school
Methods [4]
- Pre-participation physical examination
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Four-question screening for SCD risk in children
- Any prior unexpected loss of consciousness (e.g., syncope or seizure)
- Any dyspnea or chest pain associated with exercise
- Any relatives who unexpectedly died before 50 years of age
- A family history of cardiac conditions that can cause sudden SCA in children and young adults (e.g., HCM, cardiac channelopathies)
Routine ECG screening is not recommended due to the risk of false-negative and false-positive results. [2][3]
Perform the standardized pre-participation physical examination at least 6 weeks before the patient starts a new activity to allow sufficient time for additional testing if necessary. [3][6]
Management of individuals at increased risk of SCD
The following applies to any child or young adult with suspected increased risk of SCD (e.g., based on screening, history, and/or examination).
Approach [1][4][7]
- Defer clearance for competitive sports and high-intensity physical activity pending further evaluation.
- Obtain a 12-lead ECG.
- Refer to a pediatric specialist (e.g., cardiology or electrophysiology) for additional diagnostic evaluation.
- For patients with positive family history in a first-degree relative, see:
Targeted diagnostic testing [1][4][7]
Additional diagnostic evaluation depends on the suspected underlying condition.
- Echocardiography: to evaluate for structural heart disease and assess cardiac function
- Exercise stress testing: to assess for exertion-related arrhythmias or CPVT
- Ambulatory ECG monitoring: to evaluate for arrhythmias
- Advanced imaging (cardiac MRI or CT): for a detailed evaluation of heart anatomy and function
- Genetic testing: to assess for inherited cardiac conditions (e.g., cardiac channelopathy, certain cardiomyopathies)
Refer first-degree relatives of individuals with inherited cardiac conditions for genetic counseling and consideration of cascade genetic testing. [1][4]
Prevention
The following are strategies are used for both the primary prevention of SCA and to prevent recurrence. [2][4]
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Management of conditions associated with increased SCA risk [1][8]
- Pharmacological treatment (e.g., beta blockers for patients with LQTS)
- Procedural treatment, e.g.:
- Catheter ablation for treatment of WPW
- Surgery for an anomalous coronary artery [9]
- Activity modification: Restriction from sports participation should be individualized based on specific underlying diagnosis and activity intensity.
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Implantable cardioverter defibrillator placement [10]
- Indications include previous SCA due to a ventricular arrhythmia from an irreversible cause.
- May be considered for primary prevention in selected patients at increased risk of SCA
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Institutional preparedness [4]
- Schools and sports facilities must have written, practiced emergency action plans for cardiac emergencies.
- Staff should have immediate on-site access to an AED and be trained in high-quality CPR and AED use.
- Optimal response to recognized cardiac arrest includes:
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