Whilst most people at least have an idea of what a defibrillator is, they may still not be sure exactly what it does to the heart.

Most of us know what defibrillators are, or at least what they look like, because we see them in movies and TV shows all the time. Normally we see them used in the ER but sometimes it is an EMT.

We recognize the twin paddles, the high-pitched whine of the device charging and the frantic calls of “clear!” before the pads are applied and the patient jerks dramatically as electricity surges through them.

All very dramatic, right? Whilst a defibrillator can be as effective as they show in the movies, things aren't always so straightforward. There is more than meets the eye when it comes to these remarkable devices.

What Are They Used For?

Contrary to popular belief, defibrillators are not used when a patient has a heart attack, at least not in the early stages. They are in fact only used in the treatment of cardiac arrest.

What Is Cardiac Arrest? 

A heart attack involves a blockage of blood flow to a part of the heart itself, which could be caused by heart disease or blockages in arteries. It should be noted however that a person suffering from a heart attack could slip into cardiac arrest at any moment, so you should keep an eye out for the symptoms of cardiac arrest:

  • They will become unconscious
  • They will be unresponsive
  • They either won’t be breathing or won’t be breathing normally

Cardiac arrest is caused by the electrical rhythms that control the heart becoming disrupted. This leads to the heart either pumping erratically or stopping pumping blood altogether, and you don’t need to be a medical expert to know that’s bad news!

People suffering from cardiac arrest need immediate emergency treatment or they will quickly die. One element of this emergency treatment is CPR, which is designed to artificially pump oxygenated blood around the body, keeping the patient alive as long as possible.

Another very important treatment is via a defibrillator.

How Does a Defibrillator Work? 

To understand what a defibrillator does, you need to know the definition of the word fibrillation. This is medical term that refers to the state the heart will be in during cardiac arrest. Basically, it is a trembling/quivering of the heart as it tries to pump but can’t because of it’s ineffective electrical rhythms.

The word "defibrillator" comes from adding “de” to the root word "fibrillation", so as you might have guessed that means it's designed to stop the fibrillation of a heart.

How does it do this? Well, as we mentioned above, a cardiac arrest is caused by disruption of the heart’s electrical rhythms. A defibrillator works by using large amounts of electricity to try to shock the heart back into its regular rhythm. In other words, to help it start beating again.

To achieve this it uses a relatively high charge of electricity, usually in the region of 200 to 1000 volts. To give you an idea of the energy used, each defibrillator discharge zaps the heart with enough energy to power a lamp for several seconds.

What Kinds Are There? 

They typical types of defibrillator we see on TV are the heavy-duty medical versions carried in ambulances and in ER departments. They are individual paddles that the doctor or EMT rub together before applying to the patients chest (though in real life they don’t need to be rubbed together, it just looks cool on TV!)

Unless you are a medical professional, you will never use one of these machines. Instead, if the worst happens and you see someone collapse and go into cardiac arrest, you will be using an Automated External Defibrillator, or AED for short.

These devices are often found in public places such as offices, restaurants, bars and buses. They work in exactly the same way as a full-size defibrillator found in a hospital, but they are specially designed to be used by someone with limited or even no medical training at all.

They will literally walk you through how to use them step by step with both written and verbal instructions. Yes, the AED will even talk to you! They are also operated by a simple, usually color-coded button interface.

Whilst they are designed to be easy to use, if there is an AED in your workplace it would be a good idea to familiarize yourself both with its exact location and how it is used. A cardiac arrest is extremely stressful after all, and time is also an important factor. Knowing how to us the AED in advance may help to make using it in real life that little bit easier.

Does it Work? 

Sadly, it is not possible to save every victim of cardiac arrest. However, timely use of a defibrillator when paired with CPR can greatly increase the patient’s chances of survival.