Claude S. Beck, an American surgeon, performed the first recorded example of successful defibrillation on a human being in 1947. Based on the theory that an electrical shock could restart a heart that had gone into cardiac arrest, he built a machine capable of delivering the necessary shock.
He tested the device on a 14-year-old boy whose heart stopped during surgery, successfully restarting it after two attempts.
However, the theory that electrical shock could restart the heart dates back nearly 200 years prior to the first successful defibrillation. Experiments on chickens and dogs in the 18th and 19th centuries showed that electricity could both stop the heart and then restart it again.
In 1933, Popular Mechanics Magazine published an article about a precursor to the defibrillator that involved cranking a generator to the right frequency after inserting a needle through one of the spaces between the ribs into the heart to deliver the shock.
The device was called the “Hyman Otor” after its inventors, Dr. Albert Hyman and his brother. The headline of the Popular Mechanics article also referred to it as a “Self-Starter for Dead Man’s Heart.”
An estimated 25% of all human deaths involve sudden cardiac arrests (SCAs). Quick action is necessary to save the life of someone whose heart has stopped, yet most episodes of SCA occur outside of the hospital. The most common interventions in cases like these are cardiopulmonary resuscitation and defibrillation with an automated external defibrillator (AED).
Defibrillators are among the most useful life saving tools available in an emergency situation involving arrhythmia, or an abnormal heart rhythm, that can very quickly end in a fatality.
In the past, defibrillation was a medical procedure that only those with the proper training could perform. Today, however, there are AEDs that almost anyone can use. Because they are also portable, public places in communities around the nation are making them available in case of an emergency.
Research shows SCA survival rates of up to 40% in communities that have comprehensive AED programs that include training. By contrast, the survival rate for SCAs outside the hospital setting is less than 10% when AEDs are unavailable.
Electrical signals to the heart keep it beating at a regular rhythm. If something happens to disrupt the signals, such as a heart attack or illicit drug use, the fibers of the heart muscle can start fibrillating, or quivering. Fibrillation prevents the heart from pumping blood and oxygen effectively to the body’s major organs.
There are two types of fibrillation that can occur:
Atrial fibrillation is more common, but ventricular fibrillation is more serious and therefore more likely to require external defibrillation on an emergent basis.
A defibrillator works by delivering an electric shock to the heart. This allows normal conduction of the heart’s electrical impulse to resume by depolarizing the cardiac muscles.
Atrial fibrillation is usually not a medical emergency and is more often treated with an implantable defibrillator, sometimes called a pacemaker, which works on the same principle as an emergency external defibrillator on an ongoing basis.
Automatic external defibrillators are available for either professional use or public access. Professional use AEDs are those used by trained paramedics and emergency medical technicians.
Public access AEDS are intended for use in an emergency situation by people who have received little or no training. They are frequently available in public locations such as the following:
Due to studies supporting the life saving potential of public access AEDs, some locations are now required to obtain them. These requirements vary according to state laws.
At first, defibrillation was an invasive procedure that only a trained physician could perform. It was necessary to apply the paddles directly to the heart, which required a surgical procedure to open the patient’s chest.
An electrical engineer named William Kouwenhoven had been working since 1925 to develop a device that could deliver a jolt of electricity to the heart externally, without having to open up the chest. He was trying to come up with a device that power companies could use in the event of the accidental electrocution of workers.
The idea was that a defibrillator would be available to resuscitate workers on site.
Kouwenhoven successfully performed a closed-chest defibrillation on a dog nearly 30 years later, in 1954. Two years after that, in 1956, Paul Zoll used a modification of Kouwenhoven’s design to perform the first successful external defibrillation on a human being. However, these external defibrillators were not portable, and so were impractical for use outside a hospital setting.
It was the mid-1960s before a portable defibrillator was invented by Frank Pantridge, a cardiologist in Northern Ireland sometimes known as the “Father of Emergency Medicine.”
Though portable, this defibrillator was a bit ungainly, weighing over 150 pounds. This model used car batteries as its source of power, which may have been the reason it was so heavy. By the end of the decade, Pantridge had dramatically improved his design, producing a much lighter device, weighing just over six pounds. Needless to say, the new device was much easier to carry around.
However, while the new defibrillators were more portable, they were still difficult for people who didn’t have medical training to operate.
The next advancement came in 1978 when the first automatic defibrillator was invented.
An AED has the ability to detect ventricular fibrillation and cardiac arrest on its own. If it senses that defibrillation is necessary, it can automatically deliver the necessary electric shock. If it senses that there is no need for defibrillation, it will not activate at all. This is advantageous for several reasons:
As more communities adopt comprehensive AED programs, hopefully this scenario will become less and less common. However, if you believe that a patient is in cardiac arrest and there is no AED available, it is most important to keep the patient’s blood circulating. If you have training in cardiopulmonary resuscitation (CPR), you can perform chest compressions and rescue breathing.
However, even if you do not have the necessary training, you can still perform Hands-Only CPR, which dispenses with the rescue breathing in favor of chest compressions only.
Using both hands, push hard on the center of the chest in a rapid manner, aiming for two compressions per second for a total of 120 per minute. This simulates the pumping motion of the heart and keeps the blood circulating until help arrives.
In 2015, the Food and Drug Administration published a final order requiring that manufacturers of AEDs and their necessary accessories, such as pad electrodes and batteries, file an application for premarket approval.
The FDA recommends transitioning to an approved defibrillator or, if purchasing one for the first time, checking that it is approved before acquiring it. After February 21, 2021, manufacturers may no longer market AED systems and accessories that do not have approval. As a result, accessories for non-approved systems may no longer be available.
Since the survival chances for a patient in cardiac arrest are better the sooner that an AED is administered, efforts to make AEDs more accessible should be a priority.
This may involve an easy-to-use universal registration system for public access AEDs and/or a smartphone app showing where the closest AED is located. Efforts to make AEDs more affordable could mean that people could have private defibrillators in their cars or homes. At the very least, it could mean that AED access becomes available in an even greater number of public places.
People must be made aware of the signs of SCA and become familiar with AEDs and how easy they are to utilize. Most people have no idea what an AED is, even today. This will involve training and awareness campaigns, at least.
Also, bystanders should know that they are protected under the “Good Samaritan Laws” and will not be held legally responsible for a rescue attempt with an AED. This fear has caused hesitation to attempt a rescue with an AED for many.
Increased FDA regulation of defibrillators may prompt manufacturers to follow the examples of Kouwenhoven, the Hyman brothers, and especially Frank Pantridge to look for methods of improving their product in more creative ways.