What is a Defibrillator?

NewsGuard 100/100 Score

Defibrillation is a procedure used to treat life threatening conditions that affect the rhythm of the heart such as cardiac arrhythmia, ventricular fibrillation and pulseless ventricular tachycardia.

The procedure involves the delivery of an electric shock to the heart which causes depolarisation of the heart muscles and re-establishes normal conduction of the heart’s electrical impulse. The machine used to deliver this therapeutic shock to the heart is called a defibrillator.

The different types of defibrillators used include external defibrillators, transvenous defibrillators and implanted defibrillators.

Defibrillation was first presented by Prevost and Batelli, two physiologists from University of Geneva, Switzerland in 1899. In animal studies, they observed that small electric shocks delivered to the heart could trigger ventricular fibrillation, while the delivery of large electrical charges could reverse the fibrillation.

Young Boy Taka Comes Back From Dead!

In 1947, the procedure was used for the first time in a human patient. Claude Beck, Professor of surgery, at Case Western Reserve University treated a 14 year old boy undergoing a surgical procedure for a chest defect and managed to restore a normal sinus rhythm in the boy’s heart.

The early forms of defibrillator delivered a charge of between 300 and 1000 volts to the heart using “paddle” type electrodes. However, the units had major drawbacks such as the need for open-heart surgery, the transformers were large and difficult to transport, and post-mortem examination showed the technique was damaging to the heart muscles. Furthermore, the technique was often unsuccessful in actually reversing ventricular fibrillation.

In the 1950s, an alternative method of delivering an electric shock to the heart was pioneered by V.Eskin and colleague A. Klimov from the USSR. Rather than the paddle electrodes used in open heart surgery, the closed-chest device could apply a charge of over 1000 volts through nodes applied to the outside of the chest cage.

It was in 1959 that Bernard Lown and engineer Barouh Berkovits developed a way of delivering the charge using resistance to create a less strong sinusoidal wave that would last 5 milliseconds using paddle electrodes. The researchers also established the optimal timing regarding when shocks should be delivered, which enabled application of the technique in other cases of arrhythmias such as atrial fibrillation, atrial flutter and one form of tachycardia.

This technique was termed the Lown-Berkovits waveform and it became the standard defibrillation treatment to be used into the late 1980s. Thereafter, the biphasic truncated waveform (BTE) was adopted as an equally effective waveform that required less charge to achieve defibrillation. The unit was also lighter to transport. The BTE waveform in conjunction with automatic transthoracic impedance measurement, forms the basis of the modern defibrillator.

Today’s portable defibrillators were introduced in the early 1960s by Prof. Frank Pantridge in Belfast. Today, these tools form an essential part of the equipment found in an ambulance.

A further development was the implantable cardioverter-defibrillator (or ICD), which was developed at Sinai Hospital in Baltimore by a team of people that included Stephen Heilman, Alois Langer, Jack Lattuca, Morton Mower, Michel Mirowski, and Mir Imran at Sinai Hospital in Baltimore. The device was made by Intec Systems of Pittsburgh.

Further Reading

Last Updated: Jun 19, 2023

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Mandal, Ananya. (2023, June 19). What is a Defibrillator?. News-Medical. Retrieved on May 23, 2024 from https://www.news-medical.net/health/What-is-a-Defibrillator.aspx.

  • MLA

    Mandal, Ananya. "What is a Defibrillator?". News-Medical. 23 May 2024. <https://www.news-medical.net/health/What-is-a-Defibrillator.aspx>.

  • Chicago

    Mandal, Ananya. "What is a Defibrillator?". News-Medical. https://www.news-medical.net/health/What-is-a-Defibrillator.aspx. (accessed May 23, 2024).

  • Harvard

    Mandal, Ananya. 2023. What is a Defibrillator?. News-Medical, viewed 23 May 2024, https://www.news-medical.net/health/What-is-a-Defibrillator.aspx.


  1. James Markiewicz James Markiewicz United States says:

    When is it determined that a replacement of the defibrilater is necessary, and is age a factor?

  2. Gar Pratt Gar Pratt United States says:

    I'm getting a ICD or Defibrillator put in. Can I still use my Lincoln 225 stick welder or buzz box in my garage at home. I don't use it all the time, just to make repairs. Also I'm a retired bodyman do some side work. Is it ok to use a elec gringer to remove paint. Thank U.

  3. ZAP
    Ollie Armstrong Ollie Armstrong United States says:

    I just had the ICD installed two days ago. im just praying it works.

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Patients affected by depression more likely to stop taking their heart medications