There are two primary nonshockable cardiac arrest rhythms: asystole and PEA. Asystole indicates a lack of ventricular electrical activity and portends a poor prognosis or end-stage diagnosis. PEA consists of a multitude of organized cardiac rhythms in which the patient is pulseless, but the monitor shows an organized rhythm. However, by definition, PEA excludes VF, pVT, and asystole. 

The treatment of these two cardiac arrhythmias includes:

• Immediate and excellent BLS, 
• Early defibrillation if necessary, and 
• Initiation of ACLS and, eventually, 
• Post-arrest care.

ACLS Adult Cardiac Arrest Algorithm