What is Ventricular Fibrillation (V-fib?)

What is V-fib?

Ventricular fibrillation is a life-threatening arrhythmia caused by disorganized electrical signals that make the lower chambers of the heart (ventricles) quiver or twitch rather than beat normally. This creates an electrical disruption and prevents the heart from pumping blood, leading to cardiac arrest. Ventricular fibrillation is an emergency that requires immediate medical attention.

Ventricular fibrillation (V-fib) vs. ventricular tachycardia (V-tach)

Although both are types of life-threatening arrhythmia, ventricular tachycardia (V-tach) differs from ventricular fibrillation (V-fib) in that the heart beats quickly in a more organized pattern rather than in an irregular rhythm. However, episodes of V-tach can lead to V-fib or cardiac arrest.

Signs & Symptoms of Ventricular Fibrillation


Ventricular fibrillation can occur suddenly and without warning. A person experiencing ventricular fibrillation symptoms can lose consciousness, collapse, become unresponsive, stop breathing and go into sudden cardiac death if they don’t receive immediate appropriate medical attention.

If you believe someone may be experiencing V-fib, call 911 immediately and get medical help.

Before V-fib, a person may display signs including:

  • Shortness of breath
  • Chest pain
  • Dizziness or lightheadedness
  • Other types of arrhythmias
  • Nausea

What Causes Ventricular Fibrillation?


Although the cause of ventricular fibrillation is sometimes unknown, a disruption of the heart’s electrical signaling system can cause disordered heart rhythms. Lack of blood to the heart, also known as a heart attack, is the most common direct cause of V-fib.

Risk Factors

Risk Factors

Several risk factors and other conditions can increase your risk of developing ventricular fibrillation. Risk factors for V-fib include:

  • Previous heart attacks or arrhythmia episodes
  • Heart surgery
  • Congenital heart disease
  • Electrolyte imbalance
  • Trauma to the chest
  • Drug abuse, especially cocaine or methamphetamine
  • Medication that affects heart function
Get Care

Trust NewYork-Presbyterian for Ventricular Fibrillation Care

The experts at NewYork-Presbyterian have years of experience identifying the signs and risk factors of arrhythmias, including ventricular fibrillation. Our cardiovascular care teams are highly skilled in creating unique and comprehensive treatment plans for those experiencing from cardiac conditions.