Ventricular fibrillation

Last updated: December 19, 2022

Summarytoggle arrow icon

Ventricular fibrillation ("VF" or "V-fib") is a life-threatening cardiac arrhythmia characterized by disorganized, high-frequency ventricular contractions that result in diminished cardiac output and hemodynamic collapse. V-fib usually begins with ventricular tachycardia and appears as a very irregular rhythm with indiscernible P waves or QRS complexes on ECG. The most common underlying condition is coronary artery disease, but V-fib may also be caused by other cardiovascular diseases or external factors (e.g., drugs, electricity). V-fib is frequently preceded by ventricular flutter (“V-flut”), which features very rapid sinusoidal QRS complexes that can not be distinguished from T waves. Some patients with V-fib may present with early signs, including chest pain, palpitations, and dizziness. However, V-fib usually causes sudden hemodynamic instability that results in loss of consciousness and, ultimately, sudden cardiac death. Therefore, immediate defibrillation and resuscitation are vital for survival.

ECG findings

  • Ventricular fibrillation
  • Ventricular flutter: ventricular rates of ∼ 240–300 bpm
    • Frequently transitions to V-fib

Evaluation of underlying conditions

Interested in the newest medical research, distilled down to just one minute? Sign up for the One-Minute Telegram in “Tips and links” below.

  1. Hillier K. Magnesium Sulfate. Elsevier ; 2007 : p. 1-5
  2. Ventricular fibrillation. Updated: May 5, 2015. Accessed: February 26, 2017.

3 free articles remaining

You have 3 free member-only articles left this month. Sign up and get unlimited access.
 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer