Ventricular fibrillation

Ventricular fibrillation is a heart rhythm problem that occurs when the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in your heart (the ventricles) to quiver uselessly, instead of pumping blood. Sometimes triggered by a heart attack, ventricular fibrillation causes your blood pressure to plummet, cutting off blood supply to your vital organs.

Ventricular fibrillation, an emergency that requires immediate medical attention, causes the person to collapse within seconds. It's the most frequent cause of sudden cardiac death. Emergency treatment includes cardiopulmonary resuscitation (CPR) and shocks to the heart with a device called a defibrillator.

Treatments for those at risk of ventricular fibrillation include medications and implantable devices that can restore a normal heart rhythm.

Symptoms Causes Risk factors

Loss of consciousness is the most common sign of ventricular fibrillation.

Early signs and symptoms

A condition in which the lower chambers of your heart beat too fast (ventricular tachycardia) can lead to ventricular fibrillation. Signs and symptoms of ventricular tachycardia include:

  • Chest pain
  • Rapid heartbeat (tachycardia)
  • Dizziness
  • Nausea
  • Shortness of breath
  • Loss of consciousness

When to see a doctor

If you or someone else is having the above signs and symptoms, seek emergency medical help immediately. Follow these steps:

  • Call 911 or the emergency number in your area.
  • If the person is unconscious, check for a pulse.
  • If no pulse, begin CPR to help maintain blood flow to the organs until an electrical shock (defibrillation) can be given. Push hard and fast on the person's chest — about 100 compressions a minute. It's not necessary to check the person's airway or deliver rescue breaths unless you've been trained in CPR.

Portable automated external defibrillators (AEDs), which can deliver an electric shock that may restart heartbeats, are available in an increasing number of places, such as in airplanes, police cars and shopping malls. They can even be purchased for your home. Portable defibrillators come with built-in instructions for their use. They're programmed to deliver a shock only when it's needed.

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