Key Points about Ventricular Fibrillation

  • Ventricular fibrillation is an emergency heart condition characterized by very rapid electrical heart impulses that cut off the blood supply to the vital organs.
  • Ventricular fibrillation is often caused by heart muscle damage from a previous heart attack or issues with the electrical impulses through the heart.
  • Emergency treatment for ventricular fibrillation occurs at the time of the episode, bystanders should begin performing CPR and use a defibrillator to shock the heart back into rhythm.
  • Once the heart rhythm is restored, the doctor will treat the underlying condition.


Ventricular fibrillation is a serious type of heart rhythm disorder characterized by rapid, erratic electrical impulses. When this happens, your heart cannot pump blood effectively, and blood supply is cut off to your brain and other vital organs. A heart attack can trigger this reaction.

If you experience ventricular fibrillation, you need immediate emergency care. Emergency CPR needs to be started immediately, and an electric shock from a defibrillator needs to occur as soon as possible.

Ventricular fibrillation causes

While the cause of ventricular fibrillation is not always known, the most common cause is problems with the electrical impulses through the heart or issues in your heart’s muscle tissue from a previous heart attack.

Other causes of ventricular fibrillation include:

  • Limited blood flow to the heart
  • Cardiomyopathy
  • Sepsis
  • Issues with the aorta
  • Untreated ventricular tachycardia

Ventricular fibrillation risk factors

Factors that may increase your risk of experiencing ventricular fibrillation include:

  • A previous ventricular fibrillation episode
  • A previous heart attack
  • Congenital heart defect
  • Cardiomyopathy (heart muscle disease)
  • Use of recreational drugs such as cocaine or crystal meth
  • Electrolyte abnormalities such as potassium and magnesium

Ventricular fibrillation symptoms

Fainting or losing consciousness is the most common symptom of ventricular fibrillation. If you see someone with a known heart issue suddenly lose consciousness, seek immediate care.

Other early symptoms of ventricular fibrillation include:

  • Chest pain
  • Rapid heartbeat
  • Dizziness
  • Nausea
  • Shortness of breath

Ventricular fibrillation complications

Ventricular fibrillation should be treated immediately with defibrillation to restore normal heart rhythm. If you do not receive treatment quickly enough, you could experience long-term compilations or death. If you are deprived of blood too long, severe damage to the brain and other organs can occur. Death can occur in as little as a few minutes.

Ventricular fibrillation diagnosis

Ventricular fibrillation is an emergency and is diagnosed by first responders. Your care team can diagnose ventricular fibrillation by monitoring your heart's electrical impulses and checking your pulse.  A heart monitor will show if your heart is beating abnormally or if you do not have a pulse.

Your doctor may order tests to determine the cause of your ventricular fibrillation, including:

  • Electrocardiogram (ECG) — test to record the electrical activity of the heart
  • Blood tests — can identify certain heart enzymes that leak into the blood after a heart attack where the heart muscle is damaged
  • Chest X-ray — to check the size of the blood vessels and the heart
  • Echocardiogram — to generate an image of the heart using sound waves
  • Angiogram — to determine if your coronary arteries are narrowed or blocked
  • Cardiac computerized tomography (CT) scan — to collect images of the heart and lungs
  • Magnetic resonance imaging (MRI) — to produce images of the heart

Ventricular fibrillation treatment

Treatment for ventricular fibrillation starts with bystanders that may have witnessed an event. It is important to restore the blood flow to the body as quickly as possible to prevent damage to the organs and brain.

Your care team will perform the following to restore blood flow:

Cardiopulmonary resuscitation (CPR)

CPR can mimic the pumping motion of the heart. Anyone can perform CPR by pushing hard and fast on the person's chest, approximately 100 compressions a minute. If you are not CPR trained, do not stop to check the person's pulse, or breathe into the person's mouth.


During defibrillation, an electrical show is sent through the chest wall to stop the heart’s abnormal rhythm. In many cases, it will kickstart your heart into a normal rhythm.

Once the blood flow is resumed, your care team will perform other treatments to prevent future V-fib episodes.

Once your doctor has determined what caused your ventricular fibrillation, he or she may recommend any of the following treatments:

  • Medication — your doctor may use antiarrhythmic medicines for the long-term treatment of V-fib. Beta-blockers may also be prescribed to prevent future episodes.
  • Implantable cardioverter-defibrillator (ICD) — an ICD can monitor your heart rhythm, and if it detects a rhythm too slow, it can send an electrical signal to the heart. If it detects VT or V-Fib, it will shock your heart into a normal rhythm.
  • Coronary angioplasty and stent placement — if you have a blocked artery, an angioplasty will open the blocked coronary artery to let the blood flow freely to the heart.
  • Coronary bypass surgery — bypass surgery will help open the blocked or narrowed arteries and restore blood flow to the heart.

When to seek care

Seek emergency care immediately if you are someone you know is having symptoms associated with ventricular fibrillation.

If the person does not have a pulse, begin CPR to help the blood flow until an electrical shock can be performed. Push hard and fast, approximately 100 beats per minute, until help arrives. It is not necessary to check for a pulse or deliver breaths unless you have CPR training.

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