The defibrillator does not have a single, simple “inventor” — it evolved through several key pioneers — but the closed‑chest electric defibrillator most like what we know today is chiefly credited to William B. Kouwenhoven and colleagues in the 1950s, while the portable defibrillator was invented by Frank Pantridge in the 1960s.

Who “invented” the defibrillator?

If someone asks “who invented the defibrillator,” they are usually talking about one of three things:

  1. The first practical, closed‑chest electric defibrillator used in hospitals.
  2. The first external defibrillator you could use without opening the chest.
  3. The first portable defibrillator that could go in an ambulance.

Here is how those break down historically:

  • Early concept (animal experiments, late 1800s–early 1900s)
    • Jean‑Louis Prévost and Frédéric Batelli in 1899 showed that small shocks could trigger dangerous heart rhythms in dogs, and stronger shocks could reverse them.
* William Kouwenhoven began systematic research on defibrillation in the 1920s and 1930s on animals, studying how electricity affected the heart.
  • First surgical (open‑chest) human defibrillation – Claude Beck (1947)
    • In 1947, American surgeon Claude Beck used an electric shock directly on a 14‑year‑old boy’s exposed heart during surgery to stop ventricular fibrillation and restore a normal rhythm.
* This is often cited as the **first successful human defibrillation** , but it required opening the chest.
  • Closed‑chest external defibrillator – William B. Kouwenhoven & Paul Zoll (1950s)
    • In 1954, William Kouwenhoven and William Milnor successfully performed closed‑chest defibrillation on a dog , using paddles on the outside of the chest.
* By 1957, Kouwenhoven’s team had **“perfected the defibrillator”** into a box with cables and copper electrodes used routinely at Johns Hopkins Hospital.

* In 1956, cardiologist **Paul Zoll** carried that approach to humans, performing the first **closed‑chest external defibrillation** on a human patient and developing a practical external defibrillator for hospital use.

* Because of this, many sources credit Zoll as developing the **first modern external defibrillator** , while Kouwenhoven is credited with inventing the **closed‑chest electric cardiac defibrillator** itself.
  • Portable (ambulance) defibrillator – Frank Pantridge (1960s)
    • In Belfast in the mid‑1960s, cardiologist Frank Pantridge designed the first truly portable defibrillator , initially powered by a car battery and weighing about 70 kg.
* These devices were installed in ambulances and mobile intensive care units, fundamentally changing emergency cardiac care and earning him the nickname “father of emergency medicine.”

Mini timeline at a glance

[3] [5][3] [4][3] [2][4] [6][2] [5] [7][1][3] [4][3]
Year Person Milestone
1899 Jean‑Louis Prévost, Frédéric Batelli Show shocks can both induce and stop fibrillation in animal hearts.
1928–1930s William B. Kouwenhoven Begins systematic research on electrical defibrillation in animals.
1947 Claude Beck First successful human defibrillation on an open chest during surgery.
1954 Kouwenhoven & Milnor First closed‑chest defibrillation on a dog.
1956 Paul Zoll First closed‑chest external defibrillation on a human, key step to modern hospital defibrillators.
1957 William B. Kouwenhoven Hospital deployment of a compact external defibrillator unit.
Mid‑1960s Frank Pantridge Invents the first portable defibrillator for ambulances.
1978 Multiple developers Automated External Defibrillator (AED) with rhythm sensing introduced.

How to phrase the answer simply

If you need a one‑line answer for everyday use, you could say:

  • “The modern external defibrillator was developed in the 1950s by William Kouwenhoven and Paul Zoll, and the first portable defibrillator for ambulances was invented by Frank Pantridge in the 1960s.”

Information gathered from public forums or data available on the internet and portrayed here.