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.
Although artificial hearts have been around for some time now, there’s just one that’s approved for human use in the US, and it’s only intended to keep patients going until they can get a heart transplant.
A device being developed by the Oregon Health & Science University (OHSU), however, is designed to be a permanent fix.
In an effort to minimize the chances of mechanical failure, the device has been kept simple – unlike other artificial hearts, it has just one moving part, and no valves that could get stuck.
The OHSU artificial heart was invented by now-retired Dr. Richard Wampler, with Spinoff Company Oregon Heart starting work on the device in 2014. That company has since ceased operations, so the university itself took over development last year.
The moving part is a titanium alloy-coated hollow rod that shuttles back and forth inside a titanium tube, suspended within that tube on hydrodynamic bearings. This apparatus serves the same purpose as the two lower chambers of the heart (the ventricles), moving blood first to the lungs and then throughout the body.
Another thing that differentiates the OHSU heart from other devices is the fact that it creates a blood flow that mimics a natural human pulse, as opposed to a continuous flow. According to the university, this should minimize blood damage and clotting, plus it may also reduce the risk of gastrointestinal bleeding and stroke.
Power comes from a combined control unit/rechargeable battery pack that could be carried in a pocket or worn on a belt. It is hoped that the battery could ultimately be implanted under the skin, and then recharged using an external source.
Previous versions of the OHSU heart have been successfully implanted in cows and sheep for short periods. The scientists are now developing a smaller model that they hope to implant in sheep for three-month-long tests, which could hopefully be followed by human trials.