History of Defibrillation

The History of defibrillation most notably started in the in 1775 when Peter Christian Abildgaard, a Danish veterinarian and physician, conducted experiments on electrical countershock on animals. He succeeded in first rendering fowl lifeless by an electric shock and then reviving them by a countershock applied to the chest. Ventricular fibrillation and defibrillation were not known and could not be documented at that early date, but his report suggests he accomplished these changes long before other physiologists described them.  (Driscol TE, 1975)

A century later in 1899, Jean-Louis Prévost and Frederic Batelli, two physiologists at the University of Geneva, revived animals with a capacitor discharge delivered directly to the heart. Decades later, one of their graduate students, Lina Schtern, moved back to the Soviet Union and continued to work on the technique. A student of Schtern’s named Naum Gurvitch persisted with the method of defibrillation. He was the first to suggest using a biphasic waveform, publishing a short article in 1942 on his use of biphasic shocks to resuscitate animals, but the idea didn’t really take hold until much later.

Circuit Diagram of the Prevost Batelli Defibrillator

At the same time Schtern and later Gurvitch were working with Prevosts technique, a physician at Beth David Hospital of New York, Dr. Albert S Hyman and an Electrical Engineer C. Henry invented the Hyman Otor. This invention was  a Self Starter for the Dead Man’s Heart as featured in Popular Science in 1933. “This life saving device can be compared with the self-started of a car. When the car’s engine stalls, the starter motor turns it over until all cylinders are again firing. In the same way, when the heart stops…the needle of the Hyman Otor, as it is called, gives the four cylinder heart engine a rhythmical electrical stimulation. This starts the heart beat and maintains it until the hearts own electrical generator resumes operation.” (Physician Invents Self Starter for Dead Mans Heart, 1933)

Article page from Popular Science (Physician Invents Self Starter for Dead Mans Heart, 1933)

During this time the world was going through rapid industrialization. Transmitted electricity was poised to revolution life as we know it. At the time, very little was understood about the dangers associated with electrocution.  Companies installing electricity to new customers noticed that many of their utility linemen suffered from a high number of electrical shocks and accidental deaths. Starting in the 1920’s Consolidated Edison (Con Edison) power company funded research in several Universities to understand the lethalness of electricity and what can be done to prevent it.

One of those researchers was William Kouwenhoven an Electrical Engineering professor at Johns Hopkins. He started his work on rats in the 20’s and later in 1934 discovering a method of heart re-starting (defibrillation) on dogs.  The first use on a human was in 1947 by Claude Beck, professor of surgery at Case Western Reserve University. Beck's theory was that ventricular fibrillation often occurred in hearts which were fundamentally healthy, in his terms "Hearts that are too good to die", and that there must be a way of saving them. Beck first used the technique successfully on a 14 year old boy who was being operated on for a congenital chest defect. The boy's chest was surgically opened, and manual cardiac massage was undertaken for 45 minutes until the arrival of the defibrillator. Kouwenhoven’s open chest defibrillator, later used at John Hopkins as standard treatment for cardiac arrest, was based on AC current passed through a transformer to increase the voltage.

Until the mid 1950’s the only means of defibrillation was when the chest cavity was open. It wasn’t until 1955 and 1956 when closed chest defibrillation was pioneered by Dr. V Eskin in the USSR and Dr. Paul Zoll from the US working independently from each other. They were able to successfully defibrillate patients by placing the electrodes on the chest wall itself. The basis of Eskin’s and Zoll’s closed chest defibrillators remained AC electrical voltage. It wasn’t until 1959 when cardiologist Dr. Bernard Lown, built the first DC defibrillator

Circuit Diagram of the Kounhoven Zoll defibrillator

Claude Beck and James Rand 1947 Open Chest defibrillator

Paul Zoll's closed chest defibrillator

Lown charged a bank of capacitors to approximately 1000V with energy of 100-2000 joules and delivered the charge through a large inductance, producing a heavily dampened sinusoidal wave.  Berkowitz, an engineer developed the defibrillator into a clinical application known as the “cardioverter” in 1960. The Lown waveform was used in defibrillation for the next few decades.

The Lown DC capacitor based defibrillator

Dr. John Schuder over the period of 60’s – 80’s performed a number of studies on the waveform used for defibrillation. (Gold JH, 1977) (SCHUDER JC, 1966) In 1980 he concluded that the biphasic waveform was superior in defibrillation effectiveness. (Schuder JC, 1982) (Schuder JC M. W., 1984)

Trapezoidal waveform defibrillator

An H-bridge circuit topology of a biphasic type defibrillator

In 1996, an AED using an impedance-compensating biphasic truncated exponential waveform, introduced by Heartstream, now a part of Philips Medical Systems, was approved for use by the FDA.  Following the introduction of the biphasic waveform, the American Heart Association’s Guidelines in  2000 (AHA, 2000) affirmed evidence of the safety and efficacy of the biphasic waveform for termination of ventricular fibrillation. A notable benefit in sustaining a constant current during the first phase in the biphasic waveform ZOLL Medical introduced the rectilinear biphasic waveform. (White, New concepts in transthoracic defibrillation, 2002)

Circuit topology of the ZOLL Rectilinear biphasic waveform

Several other biphasic with slightly different morphologies are available for clinical use and have shown to achieve greater efficacy in terminating short-duration VF compared to the monophasic predecessor.  (White, New concepts in transthoracic defibrillation, 2002) (White, 2004)

Defibrillation waveforms of the different historical defibrillators

During this time, advancements in microprocessor technology allowed for the development of the portable Automatic External Defibrillator (AED.) The first AED was marketed by Cardiac Resuscitator Corporation and it integrated automatic analysis of heart ecg signals and automatically delivered a defibrillation.

The AED circuit diagram

In 1991 the American Heart Association recognized the benefit of life saving AED and launched a Public Access Defibrillation Initiative. The population of AEDs has grown from 15,000 in 1990 to 1.6million in 2009. (Shah JS, 2006)

Recent developments in Defibrillation

In 2002 the FDA approved a wearable defibrillator by Lifecore, now part of ZOLL Medical. The wearable defibrillator is worn by patients at risk for sudden cardiac arrest, providing protection during their changing condition and while permanent treatment is sought.

In 2004 the FDA approved an over the counter defibrillator, on data indicating that a large number of cardiac arrest happens in the home. The move has been controversial, but the defibrillator remains on the market. (Eisenberg, 2005)