The nurse is preparing to defibrillate a patient with ventricular fibrillation. The nurse should double-check the synchronizer switch because:

A shock will not be delivered if the synchronizer switch is turned on.


• Defibrillators do not synchronize with an ECG rhythm with a P wave or with closure of the semilunar valves.  Ventricular fibrillation requires a high-energy, unsynchronized impulse.

• The defibrillator cannot deliver an immediate, untimed shock when the synchronizer is turned on. The nurse needs to turn the synchronizer off first. 

• The synchronizer switch is turned on when cardioverting a patient's arrhythmia in synch with the ECG strip containing QRS complexes such as uncontrolled atrial fibrillation. Ventricular fibrillation does not contain a normal QRS complex.

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