No Pulse: How Doctors Reinvented The Human Heart

Article available here.

Doctors Bud Frazier and Billy Cohn of the Texas Heart Institute have developed a working
artificial heart using turbine pumps stripped from commercial LVADs (Left Ventricle Assistance Devices) that pumps blood through the body at turbine rate of approximately 10,000 rpm. The original premise for developing such a heart was that the synthetic tissues used in "pumping" artificial hearts such as those of the Jarvik series wore down in relatively small periods of time (max ~ 18 months). There are potential worries about turbine shear stress destroying blood cells and the pressure differential created by two turbines in one device that are not integrated. However, several successful trials have already gone under way.

Cohn and Frazier have kept a successfully pumping heart in their lab for several years now, but have more recently gotten approvals for in vivo trials.The most notable case is Meeko the calf, who successfully demonstrated the functionality of the heart in vivo. Probably more exciting, however, are the accounts of critical care/emergency implementation of the heart. One person, a 55-year-old man named Craig Lewis, was kept alive for five weeks on the heart until his liver failed from amyloidosis.

I think the most interesting about the article is that it demonstrates how our ability to mimic nature's so-called perfection is limited. A great parallel drawn in the article is that to da Vinci's attempts at designing a flapping flying machine. The idea seems childish now in comparison to modern aerospace engineering, but we are still only beginning to accept some of our limitations in the field of bionics, or biomimicry. It is quite ironic, looking at such a revolutionary idea coming into reality, that one of our most basic signs of life (pulse) may soon lose it's niche in the world of medicine.