# How Jarvik's Artificial Heart Uses Electric Motors to Pump Blood > 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. - **Patent:** US 4173796 - **Original title:** Total artificial hearts and cardiac assist devices powered and controlled by reversible electrohydraulic energy converters - **Owner:** University of Utah - **Granted:** 1979 - **Status:** Public domain (expired) - **Times cited:** 68 - **Field:** biotech, mechanical, semiconductors ## What it does This patent describes a system that converts electricity into hydraulic pressure to move blood through an artificial heart or assist device. It uses a reversible brushless DC motor connected to a hydraulic pump impeller. By spinning the motor in one direction, the system pushes hydraulic fluid to cause the heart's blood chamber to contract (systole). By reversing the motor's direction, it draws fluid back to allow the chamber to refill (diastole). This setup allows for a compact, integrated design that can be implanted to support or replace a failing human heart. ## What it does NOT cover - Does not cover pneumatic (air-driven) artificial hearts that rely on external air compressors. - Does not cover continuous-flow blood pumps that lack a reversible motor-driven hydraulic cycle. - Does not cover biological or tissue-engineered heart replacements. - Does not cover external blood pumps that remain outside the patient's body. ## The clever bit The innovation lies in using a single, reversible motor to handle both the filling and emptying phases of the heart cycle, which significantly reduced the weight and complexity of the device. ## Real-world examples 1. Jarvik-7 artificial heart 2. Early implantable left ventricular assist devices (LVADs) ## Why it matters This technology was central to the development of the Jarvik-7, the first artificial heart successfully implanted into a human in 1982. It represented a major shift toward self-contained, electrically powered medical devices that could potentially allow patients to live outside of a hospital setting. ## Frequently asked questions ### What does How Jarvik's Artificial Heart Uses Electric Motors to Pump Blood cover? 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. ### Who owns patent US 4173796? University of Utah owns this patent, granted in 1979. ### 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 4173796 cited by? This patent has been cited by 68 later patents that build on its ideas. ### What problem does this patent solve? This technology was central to the development of the Jarvik-7, the first artificial heart successfully implanted into a human in 1982. It represented a major shift toward self-contained, electrically powered medical devices that could potentially allow patients to live outside of a hospital setting. ### What does this patent NOT cover? Does not cover pneumatic (air-driven) artificial hearts that rely on external air compressors. **Full plain-English explainer:** https://patentbrief.org/patent/us/4173796/jarvik-artificial-heart **Original patent:** https://patents.google.com/patent/US4173796 --- _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: - [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. - [How Early Electromagnetic Pumps Moved Liquid Metal Using Magnetic Fields](https://patentbrief.org/patent/us/1647147/sound-on-film-talking-pictures) — A 1927 patent for a pump that uses electromagnetic forces to move conductive liquids without needing moving mechanical parts like pistons or impellers. - [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 the First Automatic Implantable Defibrillator Works](https://patentbrief.org/patent/us/3614954/implantable-defibrillator-mirowski) — 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. - [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.