What we’re doing here is pretty much comparable to the moon landings, said Ulrich Steinseifer. The professor of cardiovascular engineering smiles, unlocks a glass cabinet and takes out a round object made of plastic – an artificial heart.
Steinseifer and his colleagues at the Helmholtz Institute for Biomedical Engineering, part of Germany’s RWTH Aachen University and Hospital, are developing what they say is a fully implantable total artificial heart (TAH) that can operate maintenance-free in a patient’s body for many years.
Until now, artificial hearts have only been able to cover the waiting period for a real heart transplant. “Developing an artificial heart is an enormous challenge,” Steinseifer says.
The human heart is an extraordinary performer, constantly pumping blood through the body and thereby supplying all organs and tissues with vital nutrients and oxygen.
“Our heart is constantly adjusting – fully automatically,” Steinseifer says. “Sometimes it pumps faster, sometimes more slowly, depending on what we’re doing.” This is what a TAH must do.
Sometimes, a heart is so severely diseased that it has to be replaced. The best option is to transplant a donor heart from a deceased person. But in Europe and elsewhere, there is a growing shortage of donor hearts and waiting periods are getting longer, meaning that many patients die.
That’s why researchers like Steinseifer are trying to develop a TAH that can perform cardiac functions in the long term.
The world’s first artificial heart was implanted in a patient in Texas in 1969, keeping him alive for three days until a human heart was available for transplant. After implantation of the first “permanent” artificial heart in 1982 in Utah, the patient survived for 112 days.
Devices to date have had major shortcomings, Steinseifer points out. When they’re driven by compressed air, for example, an external air compressor is needed with drivelines connecting it to the heart. The lines penetrate the skin, creating a risk of infections.
The TAH under development since 2009 by the Institute of Applied Medical Engineering (AME) at the Helmholtz Institute for Biomedical Engineering has neither an air compressor nor drivelines, Steinseifer notes.
An implantable mini-computer containing an internal battery controls the drive unit, which makes the TAH beat faster or slower as needed. A coil system attached to the controller allows energy transmission through the closed skin to charge the battery, and energy to power the system is provided by batteries worn externally.
Although a team of engineers, technicians and surgeons have already put the TAH through extensive laboratory tests, they say prolonged experiments in living organisms are still necessary before it can be safely implanted in a person for the first time.