A Half-Hearted Robot

The heart is a remarkably complex organ composed of four chambers: two atria (upper chambers) and two ventricles (lower chambers). Each ventricle serves a distinct role in the circulatory system, with the left and right ventricles playing vital but different functions. The left ventricle is responsible for pumping oxygen-rich blood into the body's systemic circulation, providing tissues and organs with the necessary nutrients. In contrast, the right ventricle pumps blood into the pulmonary circulation, where it receives oxygen in the lungs.

The left ventricle is often highlighted due to its role in sustaining the body's systemic functions and is commonly studied in medical literature. However, the right ventricle possesses a unique anatomical complexity that has historically posed challenges for researchers and clinicians. Its intricate structure and distinct motion patterns make it difficult to study accurately, hindering our understanding of its function and potential dysfunctions.

Dysfunction in the ventricles, whether left or right, can lead to severe cardiovascular problems. Left ventricular dysfunction is often associated with conditions such as heart failure, where the heart struggles to pump blood effectively. On the other hand, right ventricular dysfunction may result from various causes, including pulmonary hypertension or chronic lung diseases. The complexity of the right ventricle's architecture has made it particularly challenging to assess its function in patients accurately.

Developing effective treatments for right ventricular dysfunction requires a comprehensive understanding of its complex physiology. In the future, this understanding may be greatly improved, thanks to the work of a team of engineers at MIT. They have developed a realistic robotic replica of the right ventricle that incorporates both biological tissue and synthetic components. The replica can mimic the motions and blood-pumping actions of a real heart.

The valves and thin, fibrous connections that make up the right ventricle are too difficult to reproduce synthetically, so the researchers first sourced real heart tissue from pigs. The tissue was carefully treated such that it would retain its intricate internal structures. A soft silicone layer was then wrapped around this tissue to stand in the place of the normal muscular lining. A number of inflatable, balloon-like tubes were then inserted between the natural tissue and the synthetic lining.

In order to position these tubes correctly, such that they could accurately simulate the movements of a real heart, a series of computational simulations were conducted. Confident that the system would be able to simulate the beat of an actual heart, the tubes were attached to a programmable control system that can inflate and deflate them as needed. In this way, the robotic heart can simulate both a natural heart rhythm and irregular patterns that are indicative of particular types of dysfunction.

A clear blood-like liquid was used to test the pumping ability of the device. Using an internal camera, it was discovered that the artificial heart’s pumping power and internal structures matched up nicely with previous observations made in live animals. These observations made it clear that this system has real-world utility in studying heart function.

In another experiment, a variety of devices were implanted into the heart’s defective valve. The team was then able to assess how well each device worked in restoring normal function. This proved that the robotic heart could be useful in selecting optimal treatments for leaky valves, or in testing other medical devices.

Because of the reliance on natural heart tissue, the robotic heart can only function realistically for a period of a few months before it degrades. The team is presently exploring options to extend the lifespan of the device so that longer-term experiments can be conducted. They are also considering the possibility of producing a robotic left ventricle to provide a more complete simulation platform.