How Does a Defibrillator Work?

An automated external defibrillator (also known as an AED) is used to give a shock to a heart that has gone into cardiac arrest. This machine can often effectively treat ventricular fibrillation (VF), which is an abnormal heart rhythm. When a person is suffering from this abnormal rhythm, the heart isn’t able to circulate blood through the body effectively. Both CPR and a defibrillator can help save a person’s life, and the sooner one is used, the better the chances of survival are.
Anyone that has had AED training can use this machine. After being guided with instructions, prompts and pictures, any person could learn to set the AED to automatically know whether a shock should be administered. When properly used, the defibrillator can help get the heart pumping again.
How a Defibrillator Works
The AED takes an ECG/EKG monitoring of the heart and the information provided will determine whether the person is suffering from ventricular fibrillation or is affected by a different type of heart rhythm. If a VF is indicated, the rescuer will be able to deliver a shock. If not, the AED won’t be operational. It will deliver a ‘No Shock’ instruction.
The AED will provide instructions for its use and it’s crucial that anyone using the machine follow these instructions to the letter. The defibrillator will tell you not to touch the person during its initial analysis and when the shock is administered. If the victim is moved or touched while the analysis is taking place a false positive may be recorded. If a person touches the victim during the delivery of the shock, the effects could be dangerous for the person operating the AED.
The AED sends electricity to the heart to stun it, which often halts and corrects the ventricular fibrillation. CPR must be resumed following the shock to help get the heart beating again. It can take as long as 10 minutes for the heart to recover from a cardiac arrest situation – during this time, CPR must be continued.
Find out more about AEDs at, or contact us today to find out more about AED training. The sooner you receive professional training on the use of a defibrillator, the sooner you’ll be able to step in and take action if a person suddenly goes into cardiac arrest.