Ventricular Fibrillation and Pulseless Ventricular Tachycardia

VF/Pulseless VT

Treatment of Ventricular Fibrillation (VF) and Pulseless Ventricular Tachycardia (VT) is included in the Cardiac Arrest Algorithm. VF and pulseless VT are shockable rhythms and treated in similar fashion. Asystole and PEA are also included in the cardiac arrest algorithm but are nonshockable rhythms.

Ventricular fibrillation and ventricular tachycardia are treated using the left branch of the cardiac arrest arrest algorithm. Click below to view the cardiac arrest algorithm diagram. When done click again to close the diagram. Cardiac Arrest Algorithm Diagram» or Members Download the Hi-Resolution PDF Here.

Many of the patients that experience sudden cardiac arrest demonstrate VF at some point in their arrest, therefore, training emphasis is placed on the cardiac arrest algorithm.

Rapid treatment of VF using the cardiac arrest algorithm has been established as the best scientific approach to restoring spontaneous circulation.

There are several important points that should be considered when initiating the cardiac arrest algorithm:

  • High-quality CPR should be performed until the defibrillator is attached the patient.
  • Interruptions in chest compressions should be kept to a minimum.
  • Rapid use of the defibrillator should be emphasized.
  • If possible, use a manual defibrillator over an AED since the use of the AED can result in prolonged interruptions in chest compressions for rhythm analysis and shock administration.

No longer are stacked shocks used. CPR is resumed for 5 cycles between each shock.

Defibrillation and the Shock

Most defibrillators used today are biphasic. Biphasic means that the electrical current travels from one paddle to the other paddle and then back in the other direction. The biphasic shock also requires less energy to restore normal heart rhythm and is believed reduce skin burns and cellular damage to the heart. When using a biphasic defibrillator in VF and/or pulseless VT, you will use a dose of 120-200 Joules to shock. Start with 120J and increase the dosing in a stepwise fashion as needed. (Example: 120 J » 200 J » 300 J » 360 J.)

To ensure safety during the shock, providers should always announce the following statement, “I am going to shock on three. One, I’m clear…Two, you’re clear…Three, everybody is clear.”

Do you know the difference between defibrillation, synchronized cardioversion, and unsynchronized cardioversion? Find out here.


A vasopressor is a medication that produces vasoconstriction and a rise in blood pressure. The vasopressors that can be used in the treatment of VF/Pulseless VT are epinephrine and/or vasopressin. Epinephrine is primarily used for is vasoconstrictive effects. Vasoconstriction is important during CPR because it will help increase blood flow to the brain and heart. Vasopressin is also used for its vasoconstrictive effects and has been shown to have effects similar to those of epinephrine.

Rhythm checks should be performed after 5 cycles of CPR. Limit rhythm checks to less than 10 seconds to minimize interruptions in CPR

Antiarrhythmic Drugs

Amiodarone, lidocaine, and magnesium are antiarrhythmic medications that are used in the pulseless arrest algorithm.


  1. Linda says

    Thanks for the site. I take me ACLS tomorrow and I have been out of it for some time now. It’s nice to have a site that I can refresh/learn the basics so I don’t feel totally lost in class!