Ventricular Fibrillation – Causes, Symptoms and Treatment

What is Ventricular Fibrillation?

Ventricular fibrillation (VFib or VF) is one of the most dangerous cardiac arrhythmias. Instead of contracting in a coordinated manner, the muscle fibers of the heart ventricles contract chaotically and without coordination. As a result, the heart is unable to pump blood to the body, leading to circulatory arrest within seconds. Without immediate treatment, ventricular fibrillation is fatal within minutes.

Causes

Ventricular fibrillation can be triggered by a variety of factors:

• Heart attack (myocardial infarction): The most common cause. Blockage of a coronary artery damages heart muscle tissue, creating electrical instability.
• Coronary artery disease (CAD): Chronic narrowing of the coronary arteries significantly increases the risk.
• Cardiomyopathies: Structural changes in the heart muscle predispose to dangerous arrhythmias.
• Electrolyte imbalances: Significant abnormalities in potassium, magnesium, or calcium levels can destabilize the heart electrical system.
• Electrical accidents or lightning strikes: External electrical impulses can trigger ventricular fibrillation.
• Medications and drugs: Certain substances can dangerously affect heart rhythm.
• Congenital heart conditions: Structural or electrical anomalies such as Brugada syndrome or Long QT syndrome.

Symptoms

Ventricular fibrillation typically occurs without warning. Common signs include:

• Sudden loss of consciousness
• No detectable pulse
• Absence of breathing or gasping respirations
• Bluish discoloration of lips and skin (cyanosis)
• Possible convulsive movements

In some cases, warning signs such as rapid heartbeat, dizziness, or chest pain may precede the event, but these are not always present.

Diagnosis

Ventricular fibrillation is diagnosed using an electrocardiogram (ECG). The ECG shows a chaotic, irregular pattern with no recognizable organized cardiac activity. In emergency settings, automated external defibrillators (AED) can independently analyze the heart rhythm and detect ventricular fibrillation.

Treatment

Immediate Response

Ventricular fibrillation is a medical emergency. The key immediate actions are:

• Call emergency services (911 or local emergency number): Alert emergency services immediately.
• Cardiopulmonary resuscitation (CPR): Begin chest compressions and rescue breaths without delay to maintain circulation.
• Defibrillation: The only effective treatment to terminate ventricular fibrillation is an electric shock (defibrillation), which interrupts the chaotic rhythm and can restore a normal sinus rhythm. Publicly accessible AED devices enable bystanders to perform this life-saving intervention.

Follow-up Treatment

After successful resuscitation, the patient is treated in an intensive care unit. Depending on the underlying cause, treatment options may include:

• Cardiac catheterization or bypass surgery for coronary causes
• Antiarrhythmic drug therapy (e.g., amiodarone)
• Implantation of an implantable cardioverter-defibrillator (ICD) to prevent further episodes
• Treatment of the underlying condition

Prevention

The following measures are recommended to reduce the risk of ventricular fibrillation:

• Regular cardiological check-ups for patients with known heart disease
• Management of risk factors such as high blood pressure, diabetes, and elevated cholesterol
• Smoking cessation and a heart-healthy lifestyle
• Adherence to prescribed cardiac medications
• ICD implantation in high-risk patients

References

1. Zipes DP, Jalife J. Cardiac Electrophysiology: From Cell to Bedside. 7th edition. Elsevier; 2018.
2. Priori SG et al. ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. European Heart Journal. 2015;36(41):2793–2867.
3. American Heart Association. Ventricular Fibrillation. AHA Scientific Statements; 2023. Available at: https://www.heart.org