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The Artificial Heart: Not Just a Pump

The goal of building a safe artificial heart has frustrated bioengineers for more than four decades. At last, an end could be in sight



JAMES WORRELL

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In the late 1970s American television viewers were captivated by a weekly drama called The Six Million Dollar Man, starring Lee Majors as secret agent Steve Austin. Austin was a cyborg, a flesh-and-blood man brought back from near death and bioengineered to be superhuman in strength, speed and vision. During the series's five-year run, Austin entered the popular idiom as the bionic man.

An era of technological optimism had been gathering momentum since the 1960s, in large part following the stunning successes of the space program. There was a growing confidence that American scientific ingenuity could engineer almost anything--including the human body. Indeed, at the same time that astronauts started flying into space, the government also set its sights on the gold ring of bioengineering: a permanent mechanical replacement for the human heart.

Fast forward to May 1988, when the New York Times dismissed the entire concept of an artificial human heart as the Dracula of Medical Technology, a hubristic 240-million boondoggle. The paper's editorialists opined tersely: The Federal project to create an implantable artificial heart is dead.

What happened? How did the grand hopes of bioengineering a human heart turn to such cynicism in just a decade?

There is a long answer and a short answer to that question. The long answer is complex, encompassing several strands of basic science and technology, from materials to batteries to motors and microprocessors, plus a healthy dose of marketing psychology. The Times may have been premature in writing off the whole enterprise, which many believe is more promising today than ever before. Nevertheless, deconstructing the early setbacks offers a useful lens on recent progress and further challenges.

The short answer is Barney Clark.

Clark was a Seattle dentist who, in 1982, became the first recipient of a permanent mechanical heart. Permanent is something of a grisly misnomer, because Clark lasted only 112 days. More to the point, they were 112 miserable days for the 61-year-old, who never left the hospital and was tethered the entire time to a refrigerator-size compressor powering his noisy new heart. He suffered convulsions, cognitive problems and kidney failure, then died of massive organ failure.

The mechanical heart that kept Clark alive for those months was the so-called Jarvik-7, named after its inventor, Robert Jarvik. The nation followed Clark's progress with rapt attention, fueled by daily press conferences, which turned quickly to sympathy and disappointment as the patient deteriorated. The case was a public-relations disaster for the Jarvik-7. The quality of Clark's life with his new heart was so poor that it turned public opinion sour on the idea for a decade. Four more patients would receive permanent Jarvik-7 hearts over the next few years, and one, William Schroeder, even survived 620 days, but the damage to the dream was done. In 1990 the U.S. Food and Drug Administration withdrew permission to manufacture any more Jarvik-7 hearts.

It's easy, of course, to second-guess quarter-century-old decisions, but many cardiologists today feel that implanting the Jarvik-7 was a mistake--premature given the primitive state of knowledge at the time. Visionaries were seduced by the simplicity of the natural organ's design--which really is just a four-chambered pump--and somewhat naive about its dynamic complexity. Says Alfred Bove, vice president of the American College of Cardiology: The God-given heart is a dynamically balanced, finely tuned organ, with the capacity to generate force, raise and lower pulse. It's not possible to get that in an artificial heart.

But it is possible to approximate it. And if nothing else, the Jarvik-7 experiments demonstrated that the basic concept was not flawed: they proved that people could survive for extended periods with a heartlike thing made of plastic and metal. Back then, that demonstration in itself was a dramatic step forward, and it was very good news for the 50,000-plus Americans with heart failure who die every year, some while awaiting one of the meager 2,200 donated hearts available for transplant. All of the work since the mid-1980s has been figuring out the problems with the Jarvik-7 and fixing them.

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