John Alexander Hopps

Canadian electrical engineer

• Born: 1919
• Birthplace: Winnipeg, Manitoba, Canada
• Died: November 24, 1998
• Place of death: Ottawa, Ontario, Canada

A pioneer in biomedical engineering, Hopps first experimented with applying electrical current to a failing heartbeat, laying the foundation for the artificial pacemaker that revolutionized heart care and improved the quality of life for millions of heart patients.

Primary fields: Electronics and electrical engineering; medicine and medical technology

Primary invention: Artificial pacemaker

Early Life

John Alexander Hopps was born in 1919 in Winnipeg, Manitoba, in west-central Canada. Little is known about Hopps’s childhood. With typical modesty, even after he had achieved considerable celebrity as the father of the artificial pacemaker, Hopps preferred to maintain a low profile and keep his personal life just that. He would speak of an idyllic childhood growing up amid the comforts of a middle-class life—Winnipeg at the time was considered one of Canada’s most developed urban areas despite being in a largely agricultural province and decidedly distant from the cultural and political centers of Canada. Hopps was a precocious child and evinced early on a proclivity for mathematics. Ironically, given his eventual international reputation, Hopps never considered medicine; rather, he pursued his first love: engineering. He relished the idea of how engineering, drawing on disciplines ranging from mathematics to architecture, represented the most pragmatic application of human ingenuity. He was particularly drawn to the possibilities of electricity and how directing the energy of currents promised unlimited applications. He graduated with a degree in electrical engineering from the University of Manitoba in 1941.

Immediately, Hopps headed west, accepting that year a position at the prestigious National Research Council (NRC) in Ottawa, then (as now) among the preeminent research facilities in the world, promoting a wide range of scientific, medical, and industrial research projects. He was placed in the Radio and Electrical Engineering Division. Initially, Hopps was assigned work on the problem of improving the efficiency of the pasteurization of beer using microwave rewarming. The research environment suited Hopps: As he had little patience with theoretical work, he was drawn to the assumption that engineering was particularly suited to problem-solving and to the work of trial and error as a strategy for tackling a specific problem. He quickly distinguished himself. In 1949, his division chief recommended that Hopps transfer to Toronto’s Banting Institute, where a team of medical researchers was developing pioneering applications of radio-frequency rewarming on cardiac care. Specifically, Hopps joined a research team headed by Dr. Wilfred G. Bigelow and his assistant Dr. John C. Callaghan that was investigating hypothermia, cooling the body to an extreme temperature as a technique for regulating heartbeat during experimental open-heart surgical procedures.

Life’s Work

Dr. Bigelow’s investigation into induced hypothermia was decidedly unconventional and widely considered risky. During late 1949, however, the research team had successfully lowered a dog’s body temperature to nearly 20 Fahrenheit. The resulting slowdown in the heartbeat interrupted the normal circulation and made possible an open-chest heart procedure. Problems arose, however, when procedures were attempted to revive the heart and return it to its normative rhythm. At the time, medical science had two ways to restimulate a stopped heart: a shot of adrenalin administered directly into the heart and/or a heart massage done manually by attending physicians.

During an otherwise routine experimental procedure on a dog, its heart (perfectly healthy otherwise) unexpectedly stopped. Bigelow, more out of desperation than anything else, applied an electrical probe he happened to be holding in his hand at the time directly to the sinoatrial node. The heart, to his surprise, immediately contracted after the poke. Electrical stimulation, gently applied at measured intervals, quickly returned the dog’s heartbeat to a regular rhythm without damaging any of the heart’s essential muscles or nerves. The idea intrigued the team; it was at this point that the researchers sought the help of Hopps, an electrical engineer with a specific background in temperature-control experiments. They outlined their proposal: to use electrical stimulation to regulate heartbeat. This could potentially solve the problem with reviving postoperative canines and in turn clear the way for exploring the potential of open-heart surgical procedures. The ensuing project, headed by Hopps, was a landmark moment in twentieth century medicine, the first cooperative venture of the fields of medicine and engineering, the birth of the field of what came to be called biomedical engineering.

Hopps understood the ambitious goal: externally apply an electrical stimulation to the heart that would duplicate the body’s normal contraction, thus not damaging the heart as cardiac massage so often did. Also, unlike the quick jolt of adrenalin, the constant application of a steady (and low) voltage would avoid muscle and nerve damage and would ensure long-term stability rather than a quick fix. The application of the electrical current, in turn, not only could control the pulse rate but also could be used in emergencies to restart a stopped heart.

Work on the project was swift and efficient—Hopps drawing not only on his own practical sense of problem-solving but also on the significant resources of both the NRC and the Banting Institute. Initially, Hopps recognized that any successful prototype would need an electrode capable of administering the nanosecond pulses of current needed for such delicate work. He designed the first catheter electrode designed specifically for cardiac resuscitation and stimulation. The catheter electrode would be introduced through the right external jugular vein, and an accompanying electrical generator would maintain the circuit. The Hopps Pacemaker-Defibrillator was first tested in 1950, effectively the world’s first artificial pacemaker. Hopps’s pacemaker was boxlike, roughly 30 centimeters long and several centimeters high and wide. It was powered by a standard 60-hertz household current and delivered up to 220 volts. It was tested successfully on several canines before it was introduced into patient care. Given its size, its use was restricted to operating room procedures and postoperative care. By 1957, however, the model had been sized down sufficiently to be implanted into the chest, and the era of the portable pacemaker was underway.

Hopps returned to his position at the NRC until his retirement in 1979. During that time, in addition to further developing the pacemaker, he directed important research into devices to assist the blind, to help support and even correct muscular abnormalities in the disabled, and to use ultrasound as a noninvasive diagnostic tool. More to the point, given his international celebrity as the pacemaker became a foundation of cardiac care, Hopps became a tireless proponent of the new field of biomedical engineering, founding the Canadian Medical and Biological Engineering Society and serving on numerous international boards and commissions that encouraged the new field. He championed a variety of community causes in the Toronto area well after his retirement, most notably crusades to improve medical care for children and health-style changes to improve cardiac care among the elderly. Fittingly, in 1984, Hopps himself received a pacemaker, and another later in 1997. After his death in 1998, he was hailed throughout Canada for his visionary contributions to both medicine and engineering.

Impact

Hopps’s acumen in solving the problem of electrical heart stimulation is widely credited for revolutionizing cardiac care and improving the quality of life for millions of heart patients, but there is more to Hopps’s impact. It is difficult for a contemporary audience to appreciate the magnitude of Hopps’s initial experimental prototype as an ethical issue—indeed, the moral implications raised by his pacemaker would become a central issue in the emerging field of biomedical engineering. Although such moral dilemmas never distracted Hopps, who saw the regulation of a heartbeat as a problem that electrical engineering could solve, they are part of his invention’s legacy. Indeed, applying electrical stimulation to a faltering heart had been tried before—but its success had been overshadowed by fears of public outrage. In 1926, an Australian doctor, later identified as Mark C. Lidwell, had used a 16-volt electric current to stimulate the stopped heart of a stillborn in cardiac arrest. The procedure had worked, but fears of religious objections to doctors playing God kept the incident in hospital files until the mid-1960’s, only after Hopps’s work had made this kind of procedure routine.

In addition to raising thorny questions over interfering with the “natural” course of life, Hopps’s pacemaker provides a significant example of how medical technology evolves at a remarkable pace. Because Hopps’s first working model depended on vacuum tubes, it appears cumbersome to a contemporary audience. However, once Hopps had demonstrated the regulatory power of an electrical current applied directly to the heart as a way to stimulate rhythmic beating, engineers across the globe worked quickly to make the device portable, first as an external model that strapped to the chest but ultimately as the familiar battery-driven device inserted directly into the heart. The evolution of the pacemaker is a landmark case in the cooperation of engineering and medicine, a groundbreaking confluence that has led to major advances in areas as diverse as brain surgery, eye care, pulmonary treatment, and nerve damage repair.

Bibliography

Greatbatch, Wilson. The Making of the Pacemaker: Celebrating a Lifesaving Invention. Amherst, N.Y.: Prometheus Books, 2000. Accessible account of the groundbreaking work of one of the premiere biomedical engineers after Hopps who headed the development of the implantable pacemaker. Helpful explanations of the general principles of pacemaker technology with clear illustrations.

Jeffrey, Kirk. Machines in Our Hearts: The Cardiac Pacemaker, the Implantable Defibrillator, and American Health Care. Baltimore: The Johns Hopkins University Press, 2001. Scholarly assessment of the impact of the revolution in cardiac care made possible by Hopps’s contribution. Focuses on the socioeconomic implications of long-term heart care and increased longevity in cardiac patients. Extensive bibliography.

Montaigne, Fen. Medicine by Design: The Practice and Promise of Biomedical Engineering. Baltimore: The Johns Hopkins University Press, 2006. Articulate defense of biomedical engineering, with generous anecdotal evidence of its effectiveness. Includes a significant discussion of pacemaker technology as evidence of how technology both increases life expectancy and quality of life.

Reiser, Stanley Joel. Medicine and the Reign of Technology. New York: Cambridge University Press, 1981. Landmark treatise that lays out the fundamental arguments and issues of the new field of biomedical engineering. Investigates the relationship between revolutionary medical procedures and quality of life issues, medical costs, and religious biases. Thoughtful, provocative, and careful to avoid taking sides. Extensive bibliography.