Sudden Cardiac Arrest (SCA) is a life-threatening emergency that occurs due to an abrupt and unexpected loss of Heart function, leading to a loss of consciousness and causing the affected person to collapse.

SCA can be fatal if not treated immediately. Emergency care or a prompt response from the bystanders determine the prognosis of Children who suffer an SCA (1).

Read this post to learn more about the causes, risks, symptoms, diagnoses, treatments, and prevention of sudden cardiac arrest in children.

Causes Of SCA In Children

Several factors can cause cardiac arrest in children. The following are a few of the common conditions that may lead to SCA in children (1)(2)(3).

1. Hypertrophic cardiomyopathy

It is an inherited congenital heart muscle disorder that often goes undetected. The disorder is the most common cardiovascular cause of SCA and occurs in about 1 in 500 to 1,000 children.

In children with hypertrophic cardiomyopathy, the ventricles (muscle cells in the heart’s lower chambers) thicken, leading to abnormal heart rhythm, especially during exercise.

The disorder can lead to obstruction of blood flow from the heart and cause unconsciousness and irregular heartbeat.

2. Coronary artery abnormalities

A defect in the connection between the coronary arteries and the heart can lead to a decreased blood supply to the cardiac muscles during exercise and cause cardiac arrest. The condition is usually congenital but may go undetected until the children get a little older.

3. Primary arrhythmias

In some children with no structural abnormalities of the heart, SCA may occur due to underlying genetic conditions, such as Long QT syndrome and Wolff-Parkinson-White syndrome, which are characterized by abnormalities of the heart’s electrical system.

4. Myocarditis

It is characterized by inflamed walls of the heart and usually occurs due to an infection. The enterovirus is the most common cause of myocarditis in children. It can also happen due to bacterial, fungal, or parasitic infections and allergic reactions to some medications.

5. Arrhythmogenic right ventricular dysplasia (ARVD)

It is an inherited condition that causes some of the heart’s muscle tissue to get replaced by scar tissue.

6. Marfan syndrome

Marfan syndrome is a connective tissue disease that may lead to tears in the aortic blood vessel of the heart. This condition can often go undetected.

7. Commotio Cordis

It is caused due to a sudden blow to the chest and at certain points in the heart cycle. It is commonly seen in sports that use projective objects, such as ice hockey, lacrosse, and baseball.

8. Structural cardiac abnormalities

Structural problems in the heart due to congenital heart diseases, postoperative repairs, or coronary artery anomalies can also cause SCA in children.

9. Arrhythmias

An arrhythmia is a change in the regular rhythm of the heartbeat. Not all arrhythmias in children are harmful. However, the following types of arrhythmia may cause SCA in children (3)(4).

• Atrial flutter: It is a rare condition in which a short circuit in the heart causes the heart’s upper chambers (atria) to pump blood rapidly (5).

• Atrial fibrillation: Instead of beating effectively to move blood into the lower chambers (ventricles), atrial fibrillation occurs when the heart’s upper chambers begin to quiver or beat irregularly (6).

• Ventricular tachycardia (VT): It occurs when the lower chambers regulate the heart rhythm instead of the upper chambers (7).

• Ventricular fibrillation (VF): It is a severe type of arrhythmia that starts in the heart’s lower chambers. It occurs when the lower chambers quiver instead of efficiently pumping blood (8).

• Sinus node dysfunction: The SA node of the heart generates electrical impulses that start each heartbeat. A problem with the SA node may cause irregular heartbeat or improper blood pumping (9).

• Complete heart block: A complete heart block occurs when the electrical signals cannot pass from the heart’s upper chambers to the lower chambers (10).

10. Coronary artery disease

Also called ischemic heart disease, it happens when the blood vessels fail to deliver enough oxygen-rich blood to the heart due to a build-up of a wax-like substance inside the large coronary arteries. The plaque may stop some or all of the blood flow to the heart (11).

Risk Factors For SCA In Children

The following factors can increase a child’s risk for SCA (2)(3).

• Aged between 10 and 19 years
• Taking part in strenuous activities, such as athletics
• Previous history of heart attacks
• Diabetes
• Elevated LDL cholesterol
• Heart ejection fraction lower than 35%
• Known structural heart defects
• Known congenital heart diseases
• Congenital heart diseases
• Abnormal and rapid heart rate or rhythm
• Undiagnosed cardiac conditions
• Obesity
• Hypertension
• Exposure to drugs, medicines, toxins, and infectious agents
• A family history of conditions that are known to cause SCA, such as long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia (CPVT), hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular cardiomyopathy (ARVC), or other familial cardiomyopathies.
• Unexplained fainting or seizures

Symptoms Of SCA In Children

About 30 to 50% of people have warning signs or symptoms before an episode of SCA, but they are most often ignored or missed.

The following are some warning signs and symptoms of SCA (3).

• Chest pain or discomfort after exercising or playing sports
• Unexplained fainting (syncope) or near fainting, especially during or just after physical exertion
• Repeated episodes of syncope
• Recurrent seizure-like symptoms, especially while doing a physical activity or just after it.
• Dizziness or lightheadedness
• Palpitations or racing heart rate
• Unusual fatigue
• Unexplained shortness of breath
• A recent episode of viral infection with chest pain or change in stamina while exercising
• A history of a heart murmur with an undetermined cause
• History of high blood pressure
• History of a cardiac condition

Diagnosing SCA In Children

Your pediatrician might refer you to a pediatric cardiologist to confirm the diagnosis of SCA in children. The pediatric cardiologist will begin by asking in detail about the child’s symptoms, medical history, and the family’s medical history.

They would then listen to the child’s heart and suggest an electrocardiogram (ECG or EKG) to determine whether or not the child’s heart is causing a problem.

They might also suggest other tests, such as an exercise stress test, echocardiogram, or chest X-ray. In some cases, they might also send the child home with an ambulatory cardiac event monitor or Holter monitor to record their heart rhythm for a prolonged period while they go on about their routine daily activities.

After the primary evaluation, the doctor will determine if further tests are required (3).

Treatment Of SCA In Children

SCA may cause the heart to shut completely or just quiver. In either case, it cannot pump the blood effectively to the brain and the rest of the body.

SCA is a medical emergency and needs immediate attention. A failure to establish a normal heart rhythm just minutes after a cardiac arrest may lead to the child’s death.

If your child collapses, call your local emergency number and start CPR. If an AED (automated external defibrillator) is available, it must be used.

The following five steps, also called the chain of survival, must occur quickly to improve the child’s survival rate (3).

1. Quickly recognizing cardiac arrest and activating the emergency response system

The sooner the child gets treatment, the better the outcome.

2. Starting early cardiopulmonary resuscitation (CPR) with an emphasis on chest compressions

CPR manually pumps blood around the body and helps maintain the blood circulation until the normal heartbeat is restored. You can read more about how to perform CPR on children here. CPR must be continued until emergency medical service arrives or the child’s breathing is restored, and they are awake, alert, and talking. If your child suddenly collapses, you may ask people around you if someone is trained to perform CPR.

3. Using an AED for rapid defibrillation of the heart can help establish a normal heart rhythm

An AED gives an electrical shock to the heart to halt the abnormal heart rhythm and allows the heart to restore its normal rhythm.

Note: It is essential to use AED as soon as possible because a person’s chance of surviving reduces by 7-10% for each minute the normal heartbeat is not restored after a cardiac arrest (12).

4. Providing advanced life support

Advanced life support can help in preventing death in some cases.

5. Ensuring optimal post-cardiac-arrest care

Optimal care after recovery from cardiac arrest is crucial as it may help prevent recurrent episodes.

Preventing SCA In Children

The American Academy of Pediatrics (AAP) suggests the following tips that may help in preventing SCA in children (3) (11).

• Early warning signs

Identifying early warning signs and knowing how to act on them helps prevent severe complications or fatalities associated with SCA.

• Regular well-child visits

Regular wellness visits can help the doctor do a thorough physical examination and take a detailed health history.

• Family history

Keep yourself acquainted with the family history of all your blood relatives—parents, siblings, children, grandparents, aunts, uncles, cousins, nieces, and nephews. If there is anything that your pediatrician must know about, make sure to inform them.

• Community life support training

AAP recommends that everyone should receive age-appropriate life support training, including CPR. In addition, AAP recommends CPR training for school staff too.

• Broad use of automated external defibrillators

AEDs should be made available at sports complexes and athletic facilities. AEDs can safely be used by people trained to use them and other people who can read and understand instructions written on the AED.

• Implantable cardioverter defibrillator (ICD)

A pediatric cardiologist, also known as, electrophysiologist (EP) or surgeon, may implant a defibrillator in a child who has a history of SCA or is at risk of developing SCA.

An ICD is a small computerized device for defibrillation or pacing of the heart. It has wires with electrodes on the ends, and these electrodes are connected to the heart’s chambers. The device can recognize a life-threatening situation and provide a mild shock in such scenarios to enable the resumption of the heart’s normal rhythm.

It is essential to be aware of the symptoms and management of SCA in children as early intervention is the key to better survival rates. Teachers and caretakers must be given life support training. If you have a family history of SCA, inform your child’s pediatrician.

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