Machines in Our Hearts: The Cardiac Pacemaker, the Implantable Defibrillator, and American Health Care

CHAPTER 4: The Multiple Invention of Implantable Pacemakers

CHAPTER 4 THE MULTIPLE INVENTION OF IMPLANTABLE PACEMAKERS Despite the confused discussion at the Rockefeller Conference in October 1958, pacing the heart for weeks or months at a time loomed as a desirable next step in part because heart specialists had begun to realize that quite a few adults developed heart block or chronically slow heartbeats in late middle age. Between 1957 and 1960, at least eight research groups designed and tested pacemakers that were fully or partially implantable and intended to work for the remaining lifetime of the patient; all eight groups used their invention with human beings. Today a few men and women are alive who have been pacemaker-dependent for thirty years or more, but in the late 1950s and early 1960s, ‘‘permanent’’ pacing had a more limited meaning: physicians who implanted pacemakers probably hoped that their patients would survive for two or three years. Complete heart block in adults seemed a rare malady, yet there were suggestions in the medical literature that clinicians might be overlooking many cases. But this was almost beside the point: inventing an apparatus to stimulate the heart electrically for months and years would be a superb technological achievement and would open the way for other biomedical inventions using implanted circuitry, batteries, and wires. David Sarnoff, chairman of the board at RCA and a noted technological sage of the 1950s, explained what was at stake when he predicted that ‘‘miniaturized electronic substitutes will be developed to serve as long-term replacements for organs that have become defective through injury or age. . . . It is not too far-fetched to imagine a man leading a normal life with one or more vital organs replaced by the refined substitutes of the future.’’ Sarnoff added, ‘‘One day artificial kidneys, lungs, and even hearts may be no more remarkable than artificial teeth.’’1 Would the cardiac pacemaker prove to be the doorway to this electromedical utopia? Medical and engineering innovators like C. Walton Lillehei, Paul Zoll, and Earl Bakken wanted to contribute to the relief of human suffering. One cannot talk to these men without being impressed with their empathy for 84 MACHINES IN OUR HEARTS TABLE 2. THE SEARCH FOR A LONG-TERM PACING SYSTEM, 1956–1960 Group Work Begun Clinical Use Description Zoll, Belgard, Frank Boston 1956? 1960 Implantable generator, myocardial lead Senning, Elmqvist Stockholm 1957 1959 Implantable rechargeable generator, myocardial lead Chardack, Greatbatch Buffalo, N.Y. 1958 1960 Implantable generator, myocardial lead Hunter, Roth Twin Cities, Minn. 1958 1959 External generator, Hunter-Roth lead Furman, Schwedel Bronx, N.Y. 1958 1958 External generator, endocardial lead Glenn, Mauro New Haven, Conn. 1958 1959 RF pacemaker Abrams et al. Birmingham, U.K. 1958? 1960 Inductive coupled pacemaker Cammilli, Pozzi Florence, Italy 1959? 1961 RF pacemaker the stricken people they were trying to restore to some degree of health. But they were also well aware that electrostimulation of the human heart was a ‘‘deep and consequential problem’’ that would exercise their talents to the fullest and might establish their reputations in the medical and engineering communities of which they were members. Their employers and professional associates valued innovation in medical devices, admired it, and in some cases stood to profit by it. As Stuart S. Blume puts it, innovation was normatively sanctioned. Thus encouraged, the key innovators took it for granted that inventing an implantable cardiac pacemaker for long-term use was a project well worth the effort.2 By the late 1950s, eight groups from four countries were designing pacemakers for long-term use (see table 2). THE TECHNICAL CHALLENGE Physiologists and clinicians had often stimulated the human heart with electricity, but they had never placed a machine inside the body, closed the MULTIPLE INVENTION OF IMPLANTABLE PACEMAKERS 85 skin, and left the thing to function. Fully implantable pacemakers seemed practical by 1958 because two inventions of the 1940s, small batteries and silicon transistors that were tiny and drew little current, were becoming available by the mid-1950s. But numerous problems of design remained.3 The requirements for long-term pacing in the late 1950s were: — No ports in the skin through which infections could enter the body. — A small battery with high energy density and a probable worklife of two to five years, or a practical rechargeable battery. — A pulse generator small enough to implant in the patient’s abdomen. — A wire lead able to withstand tens of millions...