Version control: This document is current with respect to 2015 American Heart Association® Guidelines for CPR and ECC. These guidelines are current until they are replaced on October 2020. If you are reading this page after October 2020, please contact ACLS Training Center at for an updated document.

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Using the BLS Healthcare Provider Algorithm for Managing VF and Pulseless VT

The BLS (basic life support) Primary Survey is used in all cases of cardiac arrest. For any emergency, you first see if the patient is responsive, call EMS, and find an AED. For this case, you assess a person without a pulse; you do not have an emergency care team to work with you.

Initial Assessment:

Perform the ABCDs in the primary survey:



Watch for the patient's chest to rise and fall. Assess the patient for NORMAL breathing.


Check the patient's carotid pulse (take at least 5 seconds but not more than 10 seconds). No definite pulse? Start cycles of 30 chest compressions and 2 breaths until the AED arrives.

Defibrillation using and AED

After the AED arrives, attach AED pads to the patient's chest (see AED section for details). Turn on the AED. Follow prompts.

Is the rhythm shockable?

Resume CPR immediately for 5 cycles (approximately 2 minutes). The AED will advise you when to stop so it can analyze the rhythm. Deliver a shock if instructed to do so. Repeat cycle of CPR. If rhythm is not shockable, resume CPR immediately for 5 cycles. Check rhythm every 5 cycles. Continue until ALS providers take over or the patient starts to move.

Unclear if the patient has a pulse?

Begin CPR immediately. Do not waste time trying to be certain about a pulse. It is better to begin CPR that is unnecessary than to neglect compressions when they are needed. Do compressions on a patient with a pulse is not harmful. However, delaying CPR for a pulseless patient reduces the patient's chances of being successfully resuscitated.