The October 2022 issue of IEEE Spectrum is here!

Close bar

Completely Artificial Hearts: Coming to a Chest Cavity Near You

For patients with congestive heart failure, mechanical replacements can’t come soon enough

4 min read
Illustration of a heart in a shopping cart
Photo-illustration: Edmon de Haro

Illustration of a heart in a shopping cartPhoto-illustration: Edmon de Haro

Top Tech 2017 logo

The human heart is a marvel of engineering. Inside the chest of the average adult, that hard-working muscle beats about 100,000 times per day, pumping blood through arteries that branch up toward the brain and twine down to the toes.

So it’s no wonder that biomedical engineers have had a tough time building a mechanical replica to keep patients with heart failure alive and well. Since the 1950s, ambitious researchers have tried to build artificial hearts but have always come up short. Now, four different companies think they’ve found the right technology, and they’re out to prove it. In 2017, clinical trials and animal tests could finally demonstrate that permanent artificial hearts are ready for the clinic.

About 5.7 million people in the United States alone are currently living with a diagnosis of heart failure, meaning their hearts are gradually becoming less effective at pumping blood. Some of the worst-off patients join the waiting list for a heart transplant, but donor hearts are scarce and many people die while waiting.

Photo: Bivacor

The artificial heart from the Texas-based company Bivacor is currently being tested in calves.

The Total Artificial Heart from Arizona-based SynCardia Systems already has U.S. regulatory approval as a “bridge to transplant,” and now the company is enrolling patients in a clinical trial that’s testing the device as a permanent replacement. SynCardia CEO Michael Garippa says the trial is small—just 28 patients—because more than 1,600 temporary placements have already proven that the artificial heart is safe.

Garippa is confident that the device is durable, too, based on the simplicity of its design. “There’s nothing electronic inside the body of the patient,” he says. SynCardia’s heart has two plastic chambers to mimic the heart’s two pumping chambers, and each plastic chamber is bifurcated by a membrane with air on one side and blood on the other. A patient with a SynCardia heart carries around a 6-kilogram air compressor attached to tubes that penetrate the abdomen to deliver air to the two chambers, pushing on their membranes to propel the blood on the other side. The compressor thumps loudly at a steady rate of 120 times per minute. “It’s not a normal life,” Garippa says, “but it’s way better than these heart failure patients have ever had before.”

photo of artificial heart

photo of SynCardia artificial heartKeeping the Beat: Inside the Syncardia heart (top), air pushes against membranes to propel the blood on the other sides. The Bivacor heart (bottom) propels blood with two centrifugal impellers mounted on a common hub, which is suspended via magnetic levitation.GIFs, Top: SynCardia/IEEE Spectrum; Bottom: Bivacor/IEEE Spectrum

In France, a company called Carmat is hoping to do better. “Our system is completely silent,” says Piet Jansen, Carmat’s chief medical officer. Like SynCardia’s device, the Carmat heart also has two artificial chambers with membranes that press outward to pump blood. But instead of compressed air, it uses hydraulic fluid driven by an implanted pump. Carmat’s heart is larger, heavier, and more complex than SynCardia’s device, but its designers are proud of the sensors that determine the patient’s exertion level and the microprocessor that calculates an appropriate and changeable heart rate. Wires emerge from the back of the patient’s neck to connect to a 3-kg battery pack.

Carmat’s first feasibility study seemed rocky: Two out of four patients died within three months. But industry analyst Andrew Thompson, who recently authored a report on artificial hearts, says these patients were extremely sick—as might be expected of people who volunteer for an experimental treatment. “It was not so much a failure of the device as a failure of the body,” Thompson says.

European regulators must have agreed, because they approved the major clinical trial that Carmat launched this past August. The company expects surgeons to implant its devices in about 20 patients by the end of 2017 and hopes that its artificial heart will be certified as a permanent replacement device for Europeans in 2018.

Adults Living With Heart Failure

bar chartSources: CDC, European Society of Cardiology

Two other companies not yet at the clinical trial stage have embraced a technical approach that some experts find more promising. Both companies rejected pulsating membranes and instead use centrifugal pumps with whirling, fanlike blades that propel the blood forward, sending a constant flow through the arteries. A device from Cleveland Heart (based on technology developed at the Cleveland Clinic) kept two calves alive and healthy through a 90-day study in 2015. And in Texas, a company called Bivacor is currently conducting 90-day studies with calves in cooperation with the Texas Heart Institute. Both companies are still tweaking their designs and working toward human trials.

Gianluca Torregrossa, a cardiac surgeon who has implanted SynCardia devices and written about the progress of artificial-heart research, is eagerly watching these two companies. Torregrossa says their “continuous flow” designs have fewer points of failure. “If the device has fewer moving parts, you have better chances,” he says.

When it comes to clinical trials, all of the technologies have to prove themselves under very tough circumstances. “Doctors don’t want to refer a patient to a science project unless the patient has no options,” says SynCardia’s Garippa. If the technology works for these worst-off patients, the long wait for a reliable artificial heart may be over. The tryouts of 2017 could finally reveal an engineering marvel made by humans, not by biology.

This article appears in the January 2017 print issue as “A Make-or-Break Year for Artificial Hearts.”

This article is for IEEE members only. Join IEEE to access our full archive.

Join the world’s largest professional organization devoted to engineering and applied sciences and get access to all of Spectrum’s articles, podcasts, and special reports. Learn more →

If you're already an IEEE member, please sign in to continue reading.

Membership includes:

  • Get unlimited access to IEEE Spectrum content
  • Follow your favorite topics to create a personalized feed of IEEE Spectrum content
  • Save Spectrum articles to read later
  • Network with other technology professionals
  • Establish a professional profile
  • Create a group to share and collaborate on projects
  • Discover IEEE events and activities
  • Join and participate in discussions

Make IEEE Your Home Base

The association offers networking opportunities and professional development programs

3 min read
group of young people smiling at the camera

These IEEE members connected with each other at this year's IEEE International Conference on Robotics and Automation, held in London.


The word home evokes a sense of belonging and welcoming. IEEE aims to create a similar feeling by offering services for members at every stage of their career and by building a community among them.

IEEE President and CEO K.J. Ray Liu is committed to making IEEE the professional home for members. As he announced in his March column in The Institute, he’s doing that by “examining ways in which the organization could evolve to best meet the needs of all technical professionals in the years ahead.”

Keep Reading ↓Show less

Home Heating With Hydrogen: Ill-Advised as It Sounds

Several studies reveal serious drawbacks

3 min read
Two white boilers mounted on a wood wall, with pipes and tubes.

An old central heating boiler [left] and a hydrogen boiler inside the Hydrogen Experience Center, in the Netherlands.

Sem van der Wal/ANP/Getty Images

Hydrogen, if it comes from splitting water with renewable electricity, has its role as a climate-friendly energy source. It could help decarbonize challenging sectors like heavy industry, shipping, and aviation.

But hydrogen makes absolutely no sense for heating homes and buildings, according to a new review of several international studies. It is simply much too expensive and inefficient for that purpose, says Jan Rosenow, Europe director at the Regulatory Assistance Project, an energy think tank in Brussels, who authored the commentary published in the journal Joule.

Keep Reading ↓Show less

Modeling Thermal Management Systems for Electronics

Learn how to model conjugate heat transfer in electronic devices with COMSOL Multiphysics

1 min read

The ability to dissipate heat is one of the most important features of modern electronic devices and is usually a limiting factor in the miniaturization of these devices.

COMSOL Multiphysics includes functionality for heat transfer through conduction, convection, and radiation. Its ability to treat conjugate heat transfer, including laminar and turbulent flow as well as surface-to-surface radiation, has proven to be of great importance for the design and optimization of thermal management systems in electronics. Its multiphysics modeling capabilities also enable the study of thermoelectric effects as well as thermal–structural effects, such as thermal expansion.

In this webinar, we will demonstrate how to create models and apps for conjugate heat transfer in electronic devices. We will also give a general overview of the software’s capabilities for multiphysics modeling, including heat transfer as one of the modeled phenomena.

Register now for this free webinar!

Keep Reading ↓Show less