Modern defibrillators are very safe, easy to use, and guide you through every step of a Sudden Cardiac Arrest with clear audio instructions. You do not need medical training to use one — the device does the clinical thinking for you.
What a Defibrillator Actually Does
A defibrillator is an electrical device that delivers a controlled shock to the heart when a life-threatening arrhythmia — an abnormal heart rhythm — is detected. The device analyses the heart’s electrical activity automatically and will only deliver a shock when one is clinically appropriate.
The shock does not “restart” the heart in the way most people imagine. What it does is bring the chaotic electrical activity to a sudden stop — giving the heart the opportunity to reset and resume a normal, coordinated rhythm that can circulate blood to the brain and vital organs.
The Two Rhythms a Defibrillator Treats
Ventricular Fibrillation (VF) — the most common
VF is a rapid, erratic and completely uncoordinated electrical activity in the heart’s main chambers — the ventricles. Rather than beating rhythmically, the heart muscle goes into a chaotic “fitting” action, producing no effective pumping and no blood flow. Without defibrillation, VF is fatal. The shock delivered by an AED is designed to interrupt this chaos and allow the heart to resume a normal rhythm.
Ventricular Tachycardia (VT) — less common in cardiac arrest
VT is a fast but more organised heart rhythm. Patients experiencing VT often describe a vague feeling of being unwell — they know something is wrong but can’t specify what. VT is less commonly the presenting rhythm in Sudden Cardiac Arrest, but frequently appears after a cardiac arrest event, when the heart remains “irritable” from the episode it has just experienced.
Types of Defibrillator
You may have seen the large paddles paramedics and hospital teams place on a patient’s chest — that is an external defibrillator used by trained clinicians. There are three main types:
| Type | Who Uses It | Where You See It |
|---|---|---|
| AED / PAD (Automated External Defibrillator / Public Access Defibrillator) |
Anyone — no training required | Workplaces, schools, sporting clubs, public buildings, community locations |
| Manual External Defibrillator | Paramedics, doctors, nurses | Ambulances, hospitals, emergency services |
| Implantable Cardioverter-Defibrillator (ICD) | Surgically implanted — automatic | Patients with diagnosed cardiac conditions — implanted under the chest wall by a cardiologist |
AEDs are becoming increasingly common in communities across Australia — and are directly responsible for saving many lives each year. The more accessible they are, the more lives they save.
What If the AED Doesn’t Deliver a Shock?
A common concern — Carpet answers this directly below.
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