Can a Defibrillator Restart a Stopped Heart?

The technology we have today is simply fascinating, thanks to those who came before us. The list of achievements human civilization has performed in the last 500 years, let alone the last 100, would never have been anticipated by the people who were just beginning to explore the earth 600 years ago. 

It only makes us wonder how individuals have accumulated so much knowledge in such a short time to get to where we are today. For example, how could anyone have figured out the human body had its own electricity.

Thanks to these relentless discoveries and extraordinary minds, today’s technology includes many fantastic life-saving inventions. Now, doctors can resurrect humans who have reached death or a state close to it. They can transfer a heart from one body to another and even use an Automatic External Defibrillator (AED) to bring someone back to life.

But, although the science seems pretty incredible, what’s actually going on behind the discovery? What you may not understand is that when it comes to using AEDs, television shows are actually nothing but hyped drama. The reality of this life-saving wonder of technology is very different.

So, can a defibrillator restart a stopped heart? 

A cardiac flatline — a.k.a asystole — is a state of total cessation of the heart’s electricity, which happens when the heart stops beating owing to sudden cardiac arrest (SCA). Restarting that vitality depends on regaining the body’s natural electricity. 

Essentially, electricity to a human being is what a battery ignition is to a car. When a person's heart stops beating, it stops contracting and pumping blood to major organs throughout the body.

In this situation, an AED will not be of any help and will even be counterproductive. Instead, they’ll need cardiopulmonary resuscitation (CPR) treatment to keep the blood and oxygen flowing in their body. After that, paramedics will insert a high-dosage adrenaline injection. So, unlike the movies, one device doesn’t answer all heart-related disturbances.

Thankfully, AEDs are “smart” enough to know when a shock is not required. Only when the heart is suffering from some form of arrhythmia (a condition where the heart beats in an abnormal rhythm) will an AED be of any help. An AED will not be able to rescue someone who’s been in a serious car accident or has fallen from a building unless they’re still breathing before SCA occurs. 

It's also not unusual for a healthy person to have arrhythmia. But when it interferes with their everyday life, it’s time to consult a doctor who can examine the heart's function and give a diagnosis.

The purpose of an AED is to reset the heart when it’s going through arrhythmia by inflicting electric shocks on it. The interruption should allow the heart to return to its usual rate and rhythm. If the patient's heart isn't beating, whether irregular or not, shocking the heart won't help, and AED won't revive it. 

How Does an AED Work?

We all know that AEDs send electricity to the heart through a process called defibrillation. What you might not know is that ‘defibrillation’ is taken from the medical conditional ‘fibrillation’, a rapid and irregular beating of the heart leading to clots. The defibrillator then sends more than 300 joules of energy in a process known as electrical cardioversion. 

However, this is only a temporary solution. In order to stop the fibrillation from returning to the underlying condition, the real issue causing the arrhythmia must be addressed. 

The cardiac conduction system (comprised of cardiac muscle cells) is responsible for transmitting an electrical signal to the heart and is the eventual reason the heart stops beating. A signal is sent down to the ventricles (the lower chambers) via the cardiac conduction system, which begins its work in the right atrium (upper chamber). The cardiac conduction system then sends a signal across the heart that causes the heart to contract regular beats.

When the heart starts beating rapidly, the chambers don't have enough time to fill with blood between contractions (or beats), and the signal gets distorted. This deprives the body of its regular blood flow, which is why the person suffering from an arrhythmia may experience fainting.

Heart disease, stress, substance abuse, or scarring from previous heart attacks are all possible causes of arrhythmias. Arrhythmias are serious because they may trigger a heart attack, stroke, or even sudden cardiac arrest if your body does not pump blood correctly.

Who can use a defibrillator?

Defibrillators are very common these days. They can be available found in government facilities, schools, offices, and churches. Even though they aren't required by law, it's usually a good idea to have them on hand, particularly if the building gets a lot of footfall. A defibrillator can be used on anybody who is having a cardiac episode, and using them does not necessarily need any training since they themselves can guide the user through each step.

However, avoid using a defibrillator on someone who’s having a heart attack. A strong attack isn't caused by an electrical problem but by blocked arteries and a lack of blood flow to the heart. A person should be able to respond even if they are in pain during a heart attack, whereas in the case of cardiac arrest, they may not be responsive or able to breathe. If the individual can communicate with you and tell you which part of their chest is in pain, they are most certainly having a heart attack, and defibrillation will not be of any use to them.

The amazing thing about AEDs is that they can analyse heartbeats when the paddles are placed on the patient’s chest. If it does not detect any issue with the heart's rhythm, AEDs won’t work.  A standard AED can be used to treat children above the age of eight but must be done under the right guidance, using the appropriate pads.

A person with a pacemaker can also use a defibrillator. The presence of a pacemaker is usually a visual protrusion beneath the skin, over the left chest. When connecting the defibrillator pads, you must avoid placing them directly over the pacemaker since this will likely disrupt the heart's electrical flow. Instead, place the pad a few inches below the pacemaker's location.

Who can purchase a defibrillator?

You need a prescription in order to buy an AED, with the exception of available for home usage only models. EMCARE provides a variety of defibrillator devices, including portable versions that can be carried by someone at risk of having a cardiac attack.

AEDs are one the greatest medical inventions of all time, saving millions of lives every single year — day in and day out. If you want to learn how you can save an SCA victim's life using an AED, you can sign up for our courses available at EMCARE. For more information on AED or other equipment (and how to use them), please do get in touch with us — we’re happy to help.