WHAT DOES IT MEAN WHEN MY AED SAYS, “NO SHOCK ADVISED?”

Automated external defibrillators (AEDs) automatically analyze the heart rhythm of a victim. If ventricular fibrillation (VF or V-fib) or ventricular tachycardia (VT or V-tach) are detected, the device will automatically deliver a shock. Semi-automatic AEDs will prompt the rescuer to administer a shock. The shock can help reset or restore a normal heart rhythm.

In some cases, an AED may indicate that a shock is not advised. Although VF is the most common rhythm detected in cardiac arrest, it is not the only one. An AED is designed to deliver a shock only when VF or VT rhythms are detected. However, there are other heart rhythms associated with sudden cardiac arrest that cannot be treated with a shock from an AED.

Therefore, a “No Shock Advised” message doesn’t necessarily mean that the heart rhythm is back to normal; instead, it may mean that the victim is experiencing asystole or pulseless electrical activity; neither of which are treatable by shock.

While it’s difficult to imagine an AED not delivering a shock to someone, it also means that potential rescuers should rest assured that an AED will not shock a person unless they require defibrillation.

SHOULD I LEAVE THE PADS ON IF NO SHOCK IS ADVISED?

Yes, whether a shock has been delivered successfully or the AED initially indicates “no shock advised,” you should always leave the electrode pads on. The victim may go into VF a second time or the device may recognize a shockable rhythm. Always leave an AED on until emergency medical personnel have taken over.