• Clinical science

Ventricular fibrillation


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.





Clinical features



ECG findings

Evaluation of underlying conditions

  • Conducted during or directly after initial management of patients
  • ECG: specific findings may indicate underlying condition (see above)
  • Laboratory
  • Imaging



  • Resuscitation for V-fib
  • Post-resuscitation care
    • Intensive care monitoring
      • Control/management of vital signs and removal of acute metabolic imbalances (e.g., electrolyte disturbances)
      • Mild therapeutic hypothermia
    • Maintain application of antiarrhythmics that were used during successful resuscitation (usually IV amiodarone or IV lidocaine)
    • Consider administration of beta blockers
    • Treat underlying causes (e.g., treatment of CAD)
    • ICD; (implantable cardioverter-defibrillator) in patients without a readily reversible or treatable cause and/or with a high risk of recurrent, hemodynamically significant V-fib