How does a bionic heart work?

Swapping muscle for metal, how does this artificial organ keep blood flowing?

Image credit: BiVAC

Cardiovascular disease is one of the world’s biggest killers, accounting for 31 per cent of all deaths globally. Although a lot of cases are treatable with a heart transplant, finding a donor is becoming increasingly difficult: only around 4,000 hearts are available globally each year.

The creation of a total artificial heart (TAH) could be revolutionary for saving lives. Several iterations have been tried over the past few decades, but none have had the ability to completely copy the heart’s function for more than a few years.

The latest and arguably most promising development of a TAH comes in the form of the BiVACOR, a 3D-printed titanium pump that utilities an autonomous magnetic rotor to circulate blood.

One of the common issues found in previous TAH technology has been the physical wear and tear of a device’s moving parts. Using magnetic levitation (maglev), the BiVACOR’s central spinning rotor is magnetically suspended inside an electromagnet bearing. As electricity passes through the magnet the rotor spins, propelling the blood around the body’s arteries and veins. Maglev prevents physical wear and tear through normal friction, and it is thought to reduce the complications that would normally follow.

Smaller than a can of coke, this compact device is constructed using a form of metal 3D printing called selective laser sintering (SLS). This process involves repeated layers of fine titanium dust being melted by a laser to slowly print the final form.

The BiVACOR has shown promising results during its animal trials, with bovine (cow) subjects surviving the full 90-day test period. However, the device is still in its development stages, and no human trials have been carried out so far.      

Inside the artificial heart

Discover how BiVACOR uses magnets to ferry blood cells around the body

Image credit: Future PLC (click to expand)

This article was originally published in How It Works issue 130

For more science and technology articles, pick up the latest copy of How It Works from all good retailers or from our website now. If you have a tablet or smartphone, you can also download the digital version onto your iOS or Android device. To make sure you never miss an issue of How It Works magazine, subscribe today!