Artificial hearts have been designed and redesigned for decades, but a new one, designed by Drs. Billy Cohn and Bud Frazier at the Texas Heart Institute, goes in a totally new direction. Instead of trying to replicate the human heart's pumping, this new heart simply whirs. Someone outfitted with this new artificial heart would have no pulse, no heartbeat, at all.
The design is based on two attached ventricular assist devices, a sort of bladed rotor that pushes blood continuously rather than in pumps. It's been used before, but only to replace a single ventricle--nobody had ever tried to replace the entire heart with these devices. That's because it was assumed that the beating of a heart, which we think of as so fundamental to being alive, was necessary for the well-being of other organs as well. Turns out, not so much: the beating is only required for the heart itself. Says Cohn, to NPR
: "The pulsatility of the flow is essential for the heart, because it can only get nourishment in between heartbeats. If you remove that from the system, none of the other organs seem to care much."
Cohn compares this to the development of the airplane: at first, we saw birds and bats, and figured flying must require a flapping motion. But a more detailed understanding of aerodynamics led to the airplane, a distinctly un-organic design.
The pulseless heart has been installed in calves with success, but only one human: a 55-year-old named Craig Lewis who suffered from amyloidosis. The heart actually worked perfectly, but Lewis died from complications of the disease (complications, for the record, unrelated to his heart: it was liver and kidney failure that ended his struggle with amyloidosis). The reason I'd pick this heart? Lewis's wife noted that in place of a heartbeat, his heart hummed
. If I'm going to be a cyborg, I'm going to sound like one too, dammit.
Runner-up: This heart
was installed earlier this month in an English man. It's more proven, but the idea of a pulseless heart strikes me poetically in the right way, if we're thinking in terms of cyborgs.
Pictured: An x-ray of the pulseless heart installed in Craig Lewis.