A new bio-robotic model developed by MIT engineers simulates the function of the heart. Soft, balloon-like “muscles” (in blue) wrap around and contract the right ventricle, mimicking its real pumping action. The model could help to test new implants and devices to treat a range of cardiac disorders. [Image courtesy of the researchers]
This technology combines real heart tissue with synthetic, balloon-like artificial muscles. The researchers say it enables scientists to control the ventricle’s contractions while observing how natural valves and other structures function.
According to MIT, the engineers can tune the artificial ventricle to mimic healthy and diseased states. They manipulated it to simulate the conditions of right ventricular dysfunction, including pulmonary hypertension and myocardial infarction. Additionally, they used the artificial ventricle model to test cardiac devices, like an implantable mechanical valve.
The team says this robotic right ventricle (RRV) could offer a realistic platform to study right ventricle disorders and test devices and therapies.
“The right ventricle is particularly susceptible to dysfunction in intensive care unit settings, especially in patients on mechanical ventilation,” said Manisha Singh, a postdoc at MIT’s Institute for Medical Engineering and Science (IMES). “The RRV simulator can be used in the future to study the effects of mechanical ventilation on the right ventricle and to develop strategies to prevent right heart failure in these vulnerable patients.”
Singh and her colleagues shared details on the technology in a paper published in Nature Cardiovascular Research.
Why the right ventricle?
According to Ellen Roche, co-author and associate head for research in the Department of Mechanical Engineering at MIT, the right ventricle is a thinner muscle with more complex architecture and motion. It pumps deoxygenated blood to the lungs so it doesn’t have to pump as hard, she says.
This makes it difficult for clinicians to accurately observe and assess right ventricle function in patients with heart disease.
“Conventional tools often fail to capture the intricate mechanics and dynamics of the right ventricle, leading to potential misdiagnoses and inadequate treatment strategies,” Singh said.
To address this, the team looked to create a model that captures the right ventricle’s anatomical intricacies and reproduces its pumping function. The researchers’ model features real heart tissue because it retains natural structures that prove too complex to reproduce synthetically.
“There are thin, tiny chordae and valve leaflets with different material properties that are all moving in concert with the ventricle’s muscle. Trying to cast or print these very delicate structures is quite challenging,” Roche said.
Testing the robot heart technology
The team explanted a pig’s right ventricle, treating it to carefully preserve its internal structures. Researchers then fit a silicone wrapping around it to act as a soft, synthetic myocardium (muscular lining). Through the lining, the team embedded long, balloon-like tubes to encircle the real heart tissue.
The tubes took up positions determined through computational modeling to be optimal for reproducing ventricular contractions. Each tube connected to a control system, set to inflate and deflate tubes at rates mimicking the heart’s real rhythm and motion.
Engineers then infused the model with a liquid similar in viscosity to blood to test the pumping ability. They used a transparent liquid to observe how internal valves and structures responded with an internal camera. The team found similar pumping power and function compared to what they observed in live, healthy animals.
They could also tune the frequency and power of the pumping tubes to mimic cardiac conditions. Those included irregular heartbeats, muscle weakening and hypertension.
“We’re reanimating the heart, in some sense, and in a way that we can study and potentially treat its dysfunction,” Roche said.
What about cardiac devices?
To test the RRV’s capabilities in testing cardiac devices, the team surgically implanted ring-like medical devices of various sizes to repair the chamber’s tricuspid valve. Researchers surgically manipulated the RRV’s valve to simulate this condition. Then, they either replaced it with a mechanical valve or repaired it using the ring-like devices.
“With its ability to accurately replicate tricuspid valve dysfunction, the RRV serves as an ideal training ground for surgeons and interventional cardiologists,” Singh said. “They can practice new surgical techniques for repairing or replacing the tricuspid valve on our model before performing them on actual patients.”
According to MIT, the RRV can simulate realistic function over a few months. The team hopes to extend that, enabling the model to run continuously for longer stretches. They also have work underway to test prototypes with implantable devices.
“We envision pairing this with the left ventricle to make a fully tunable, artificial heart, that could potentially function in people,” Roche said. “We’re quite a while off, but that’s the overarching vision.”
