Definition

Ventricular fibrillation (VF) is a type of heart rhythm disorder (arrhythmia) that occurs in the heart's ventricles. This condition is rare in children. Ventricular fibrillation happens when abnormal electrical activity occurs in the cells of the ventricles. This uncoordinated electrical activity disrupts the ventricles' ability to pump blood. Instead of pumping strongly, the ventricles simply quiver (fibrillate), preventing blood from being circulated to the rest of the body.

Causes

Primary ventricular fibrillation (VF that occurs within 48 hours after a heart attack and is not associated with heart failure) is uncommon in children. It is generally caused by other medical conditions, such as:

• Electrolyte imbalances
• Use of certain medications that can cause heart rhythm disorders
• Hypothermia (body temperature falling below 35°C due to prolonged exposure to cold) or hyperthermia (uncontrolled body temperature above 40°C)
• Overdose of substances such as LSD, ecstasy, marijuana, or stimulants such as cocaine and amphetamines
• This substance can impair blood flow to the heart muscle
• If this causes damage to the heart muscle, heart rhythm disturbances may occur.
• Injury to the chest, even minor, can cause VF in boys aged 5–15, especially during sports
• Congenital heart disease, particularly after heart surgery
• Drowning
• Abnormal electrical signaling in the heart
• Lack of oxygen
• Genetic abnormalities
• Brugada syndrome, a hereditary arrhythmia disorder that poses a high risk for sudden cardiac arrest due to VF
• Inherited heart muscle disorders (cardiomyopathies)

Risk Factor

Several factors can increase a child's risk for ventricular fibrillation, including:

• Congenital heart defects such as:
• Tetralogy of Fallot
• Narrowing of the aorta
• Transposition of the great arteries, where the positions of the aorta and pulmonary artery are swapped
• History of heart surgery
• Heart failure
• Family history of congenital heart disease or arrhythmias
• Inflammation of the heart muscle (myocarditis), which can make damaged heart muscle more prone to VF
• Heart valve disorders

Symptoms

Symptoms of ventricular fibrillation caused by disrupted blood flow to organs may include:

• Dizziness
• Lightheadedness
• Palpitations
• Chest pain
• Shortness of breath
• Fainting

Diagnosis

Ventricular fibrillation can be diagnosed through blood pressure and heart rate assessments, as well as an electrocardiogram (ECG). However, the underlying cause must also be identified. The doctor will ask about your child’s medical history and conduct a physical examination, particularly of the heart, using a stethoscope to listen for abnormal sounds. The doctor will look for signs of heart conditions, such as heart failure, myocarditis, abnormal heart sounds, cardiomyopathy, or valve disease.

Additional tests to confirm the diagnosis and find the cause may include:

• Laboratory tests:
• Electrolyte levels, particularly magnesium, potassium, and calcium, as imbalances can cause arrhythmias
• Blood gas analysis to check blood pH, as an overly acidic pH can increase arrhythmia risk
• Drug testing for medications and toxins
• Radiological tests:
• Chest X-ray
• Echocardiogram
• Cardiac MRI
• Holter monitor to record electrical activity in the heart over 24 hours
• Stress test to detect arrhythmias triggered by exercise
• Electrophysiology study
• This test may be needed in children at high risk for ventricular fibrillation.
• Stimulation is performed on the atria and ventricles of the heart to see if it will cause ventricular fibrillation.

Management

Ventricular fibrillation treatment is divided into two stages. The first is to stop the fibrillation as quickly as possible to restore normal blood pressure and heart rate. The second stage focuses on preventing future arrhythmias.

Treatment options include:

• Cardiopulmonary resuscitation (CPR) or chest compressions. VF can cause cardiac arrest, so CPR is needed to keep the heart pumping blood throughout the body
• Defibrillation
• Electrical shocks are delivered to the chest to restore normal heart rhythm. This is crucial to be done as soon as VF is diagnosed
• Medications: After controlling the fibrillation, medications can help prevent future episodes
• Implantable cardioverter defibrillator (ICD): This device is implanted in the body to monitor for VF. If detected, the ICD automatically delivers shocks to restore normal heart rhythm
• Radiofrequency catheter ablation: This procedure uses energy to destroy small areas of the heart causing the VF. It is primarily a treatment for ventricular

Complications

Complications of ventricular fibrillation can include repeated fainting episodes. During VF, blood flow to vital organs is disrupted. Prolonged VF or cardiac arrest can cause permanent damage to the brain, kidneys, and liver. VF can also be fatal.

Prevention

Since VF in children is usually caused by an underlying medical condition, early detection and treatment of that condition can prevent VF. Regular checkups may help catch these conditions before they worsen. VF is usually preceded by other ventricular arrhythmias. Early detection of these arrhythmias can prevent severe complications or worsening of the child’s condition.

To reduce the risk of recurrent VF, your doctor may prescribe medications or recommend an ICD. While an ICD does not prevent VF, it can quickly detect and treat it, preventing fatal outcomes. No specific diet is recommended for preventing VF, and physical activity limitations are only recommended if there is an underlying condition that exercise could trigger.

If your child is at risk of VF, they should wear a medical ID, and those around them should know what to do in an emergency, such as calling emergency services.

When to See a Doctor?

Seek immediate medical attention if your child exhibits symptoms such as:

• Fainting
• Unresponsiveness
• Loss of consciousness
• Shortness of breath

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