# How the First Automatic Implantable Defibrillator Works

> A 1970 invention by Medtronic that monitors heart rhythms and automatically delivers an electric shock to restart the heart if it detects a dangerous malfunction.

- **Patent:** US 3614954
- **Original title:** Electronic standby defibrillator
- **Owner:** Medtronic Inc
- **Granted:** 1971
- **Status:** Public domain (expired)
- **Times cited:** 71
- **Field:** biotech, medical_devices

## What it does

The device acts as a continuous heart monitor that tracks electrical activity to identify life-threatening arrhythmias. When the system detects an abnormal heart rhythm, it triggers a high-voltage discharge to shock the heart back into a normal sinus rhythm. If the first shock fails to restore normal function within a set interval, the mechanism is designed to deliver subsequent shocks. The device remains inactive as long as the heart's electrical activity stays within normal parameters.

## What it does NOT cover

- Does not cover external defibrillators that require manual operation by a human.
- Does not cover devices that monitor blood pressure or oxygen levels rather than electrical heart activity.
- Does not cover pacemakers that only provide low-voltage stimulation for slow heart rates.

## The clever bit

The invention shifted the paradigm from external, reactive emergency care to an autonomous, internal system that waits in a standby state until it detects a specific, lethal electrical signature.

## Real-world examples

1. Modern implantable cardioverter-defibrillators (ICDs)
2. Subcutaneous ICDs (S-ICD)

## Why it matters

This patent represents the foundational technology for the Implantable Cardioverter Defibrillator (ICD). It transformed the treatment of sudden cardiac arrest by enabling a device to provide life-saving intervention without requiring a doctor or bystander to be present.

## Frequently asked questions

### What does How the First Automatic Implantable Defibrillator Works cover?

A 1970 invention by Medtronic that monitors heart rhythms and automatically delivers an electric shock to restart the heart if it detects a dangerous malfunction.

### Who owns patent US 3614954?

Medtronic Inc owns this patent, granted in 1971.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 3614954 cited by?

This patent has been cited by 71 later patents that build on its ideas.

### What problem does this patent solve?

This patent represents the foundational technology for the Implantable Cardioverter Defibrillator (ICD). It transformed the treatment of sudden cardiac arrest by enabling a device to provide life-saving intervention without requiring a doctor or bystander to be present.

### What does this patent NOT cover?

Does not cover external defibrillators that require manual operation by a human.

**Full plain-English explainer:** https://patentbrief.org/patent/us/3614954/implantable-defibrillator-mirowski

**Original patent:** https://patents.google.com/patent/US3614954

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [The First Implantable Cardiac Pacemaker](https://patentbrief.org/patent/us/3057356/implantable-cardiac-pacemaker) — Wilson Greatbatch's 1960 patent for the first successful implantable heart pacemaker that used a battery to regulate heartbeat.
- [How Jarvik's Artificial Heart Uses Electric Motors to Pump Blood](https://patentbrief.org/patent/us/4173796/jarvik-artificial-heart) — A 1977 invention by Robert Jarvik that uses a reversible electric motor to power a hydraulic pump, enabling artificial hearts to mimic the natural pumping action of a human heart.
- [How Early Cochlear Implants Used Digital Signals to Restore Hearing](https://patentbrief.org/patent/us/4063048/cochlear-implant-hearing) — A 1977 patent describing an electronic device that converts sound into digital pulses to stimulate the auditory nerve, bypassing a damaged inner ear.
- [How the First Heart-Lung Machine Oxygenated Blood](https://patentbrief.org/patent/us/2702035/heart-lung-machine-gibbon) — A 1955 invention that allowed surgeons to oxygenate a patient's blood outside the body, enabling the first successful open-heart surgeries.
- [Leonarde Keeler's Early Mechanical Blood Pressure Recorder](https://patentbrief.org/patent/us/1788434/polygraph-lie-detector-keeler) — A 1925 invention by Leonarde Keeler designed to mechanically record a patient's arterial blood pressure over time.