ventricular fibrillation also called v-fib is when the ventricles of the heart quiver and don't work properly. Next an automated external defibrillator (AED) is used to "shock" the patients heart bring it back to a normal rhythm.
I'm no doctor, but I hope this helps :)
Answer:
because V-fib is a shockable rhythem, the AED will say "Shock advised" "Charging, tell everyone to stand clear" then it will tell you to tell everyone to stand clear again and say "press the shock button." it will deliver the shock. then it will say "now begin 5 cycles of CPR."
