A new durable artificial heart

Drs Bud Frazier and Billy Cohn took out the dead heart of Craig A Lewis on March 10 at the Texas Heart Institute. Texas Heart Institute founder Dr Denton A Cooley held a news conference yesterday morning to explain how the pulseless artificial heart was designed and how the medical advancement will help Lewis and others live a longer life.

After harmful proteins built up in his heart to the point it could no longer work, Lewis lived only with the aid of external breathing, dialysis and heart support machines. The Houston man had maybe a day to live when Frazier and Cohn were given the opportunity to test their device — a pair of turbines cobbled together to mimic the function of the heart's left and right ventricles — that had been implanted only in 37 calves.

So far Lewis is recovering well, doctors say. "It was time to take this leap forward," Frazier said. The leap is an evolution away from devices that push blood into the body in pulses, like the natural heart.

Frazier was one of the earliest and probably most outspoken evangelists for a new approach, that of pumps using a tiny turbine spinning thousands of times per minute to provide a continuous flow of blood.

In 1988, he implanted the world's first left-ventricular assist device with a continuous-flow pump, and the next-generation HeartMate II pump he helped develop has now been put into 11,000 patients. Continuous flow pumps are smaller and more durable. Pulsatile pumps must beat 100,000 times a day, and 35 million times a year to match the heart.

Pumps and artificial hearts with this pumping action tend to break down in months or a few years. According to the hospital report, the new artificial heart, in which Frazier and Cohn combined a pair of modified HeartMate II pumps, caps half a century of progress and setback in the quest to replace dying hearts with machines.