Ventricular Fibrillation


Each beat of your heart is like a perfectly choreographed dance in which one misstep can throw off the whole routine. That’s the case with ventricular fibrillation, which occurs when the ventricles, the heart’s lower chambers, flutter instead of contracting. When that happens, the heart can’t pump blood, which can cause sudden cardiac death. The most serious type of arrhythmia, ventricular fibrillation is a medical emergency.


  • Chest pain
  • Difficulty breathing
  • Dizziness
  • Fast or irregular heartbeat
  • Nausea
  • Sudden loss of consciousness


  • Other types of ventricular arrhythmia, such as [“ventricular tachycardia”: link to new ventricular tachycardia content], often lead to ventricular fibrillation. Diagnosing and treating those conditions early may help prevent ventricular fibrillation.
  • If you are at higher risk for ventricular fibrillation, your physician may prescribe an antiarrhythmic medication or recommend an implantable cardioverter defibrillator (ICD), a device that rests in your chest and can deliver an electric shock to return your heart to a normal rhythm if it detects an arrhythmia.

Risk Factors

  • Aortic problems
  • Cardiac surgery
  • Certain medications
  • Congenital heart disease
  • Heart attack
  • Injury to the heart
  • Poor blood flow to the heart
  • Sepsis
  • Too much or not enough potassium in the blood
  • Weakening or thickening of the heart muscle


  • Presence of symptoms. Suspected ventricular fibrillation warrants immediate medical attention based on symptoms. The most serious is sudden collapse due to cardiac arrest. Up to one hour before collapse, you may experience chest pain, nausea or difficulty breathing.
  • Electrocardiogram. If time allows, your physician may order an electrocardiogram, a test of the heart’s electrical activity. Also known as an ECG or EKG, this test can show ventricular fibrillation as it happens.
  • Medical history and physical exam. Once you’re stable following an episode of ventricular fibrillation, your physician will ask you about your medical history, the medications you take and whether you have a family history of sudden cardiac death.


  • If you see someone suddenly collapse, it’s essential to act fast. Call 911 and perform CPR until the individual regains consciousness or emergency medical services (EMS) arrive.
  • EMS personnel will use a machine called an external defibrillator to deliver an electric shock to help the heart beat normally.
  • For long-term treatment, a physician may prescribe medication to help regulate heart rhythm or recommend an ICD.

Follow-up Care

  • If you’ve experienced ventricular fibrillation, it’s important to comply with your cardiologist’s treatment plan and follow up with him or her regularly.
  • If you receive an ICD, be sure to adhere to any activity restrictions recommended by your provider. Full recovery following implantation may take up to six weeks.
  • Tell your cardiologist about any new symptoms you experience.