The number of artificial prosthetic replacement parts available for the human body is really quite impressive. From prosthetic eyes to artificial hips and knees, there are very few parts of the human body that can’t be swapped out with something that works at least as well as the original, especially given that the OEM part was probably in pretty tough shape in the first place.

But the heart has always been a weak spot in humans, in part because of the fact that it never gets to rest, and in part because all things considered, we modern humans don’t take really good care of it. And when the heart breaks down past the point where medicine or surgery can help, we’re left with far fewer alternatives than someone with a bum knee would face. The fact is that the best we can currently hope for is a mechanical heart that lets a patient live long enough to find a donor heart. But even then, tragedy must necessarily attend, and someone young and healthy must die so that someone else may live.

A permanent implantable artificial heart has long been a goal of medicine, and if recent developments in materials science and electrical engineering have anything to say about it, such a device may soon become a reality. Heart replacements may someday be as simple as hip replacements, but getting to that point requires understanding the history of mechanical hearts, and why it’s not just as simple as building a pump.

The Heartbeat of America

While the understanding of the heart as a pump stretches all the way back to the 3rd century BCE, it took nearly 1,000 more years for medical science to advance much;  the early view of the Greek physician Galen that the heart provided heat for the body and blood moved from the venous to arterial systems via pores in the septum of the heart was not to be questioned, at least in Western medical traditions.

There’s a reason that the Dodrill-GMR artificial heart looked like a car engine. Source: National Museum of American History, CC0 1.0

Once doctors were free to explore the human heart, its structure and function became clear. The heart is a four-chambered pump made from specialized muscle tissue. The upper chambers are referred to as the atria, feeding into larger ventricles below via one-way valves to prevent backflow. The right atrium receives deoxygenated blood from the body through a large vessel called the vena cava; it moves to the right ventricles and on toward the lungs, where through a complex process of…

Continue reading: