“It’s my life!”
“Of course it is, Jack, but—”
“No!” he screamed pathetically. “I know what you’re doing, trying to make some money off of me. Look, I’d rather die. Just let me die. I’m not afraid to die; I just want to go the right way.”
I really did feel sorry for Jack. Obviously, the last thing he wanted to admit is that he needed me or modern cardiology to keep him alive. But there wasn’t much more I could offer apart from the technology with which I had been trained. And though I still wasn’t sure that a defibrillator was the right choice, once the decision was made, there was no point in ambivalence.
“I’m trying to help you, Jack,” I said, sitting down. “I’ve done everything you’ve asked me to. I even reached out to Dr. Null”—the natural healer—“for his treatment protocol, but he wouldn’t take my call. His assistant said he doesn’t even know who you are.”
(Null, I later learned, was a well-known alternative-health practitioner who denied that HIV causes AIDS, was opposed to vaccinations, and produced and sold dietary supplements for various disorders.)
“How is that my fault?” Jack barked.
“Look, Jack, I don’t want to make you do something you don’t want to do,” I said, close to giving up. “I thought you wanted the device. If you didn’t want it, you shouldn’t have come to the hospital. You’ve wasted a lot of effort for nothing.”
Outside the curtain there was rustling, probably an intern listening in. Jack straightened up. “I told you from the beginning that I thought you were too dogmatic,” he said. “Unfortunately, your medications didn’t work, and now we’re back to where we started. I don’t blame you; you’re used to telling people what to do. But it isn’t going to work with me.”
But, in the end, it did work. After getting a shot of Ativan, Jack appeared soothed and agreed to proceed with the implant. By then, I think he knew there were no other options available to him. But, pointing his finger at me in mock anger, he said, “If I hear you bragging that you finally got me, I’m going to get you.”
•
In the decades after George Mines’s trailblazing work in cardiac electrophysiology, electricity became widely available in industrialized countries. By the 1930s, 90 percent of urban residents in the United States had access to electrical power. From streetcars to lightbulbs to household appliances, electricity revolutionized the way people lived. Of course, by then scientists knew that electricity powered the heart, too. But when the heart’s wiring failed, could man-made power be used to control the heart like any automatic dishwasher? This was a challenge that occupied a generation of researchers.
One of the first steps to meeting this test was taken by the cardiologist Paul Zoll at Beth Israel Deaconess Medical Center in Boston. During World War II, Zoll was assigned to an army hospital in England, where he served as the cardiologist on a surgical team. As he watched trauma surgeons remove shrapnel from soldiers’ hearts, Zoll was struck by how excitable the heart muscle was. “You just touch it and it gives you a run of extra beats,” he wrote. “So why should the heart that is so sensitive to any kind of manipulation die because there’s nothing there to stimulate [it]?”
After the war, Zoll set out to treat patients with complete heart block, a common condition in which the heart’s conduction system becomes diseased. In complete heart block, normal electrical impulses from the atria do not reach the ventricles. The ventricles, the main pumping chambers, must generate their own rhythm through a backup pacesetter that is usually much slower than the atria’s. Patients with heart block often have a dangerously slow heartbeat. They are frequently short of breath and fatigued. They sometimes faint because of low blood flow. In rare cases, they may experience cardiac arrest and sudden death.
In his first experiments, Zoll slid an electrode down the esophagus of an anesthetized dog, positioning it a few centimeters from the left ventricle to maximize the electrical stimulus to the heart. To his amazement, he found that he could capture the heartbeat with an externally generated impulse. Zoll realized that in an emergency, there would be no time to pass an electrode into the mouth and down the food pipe of an unconscious patient, so in his next set of experiments, he dispensed with the esophageal electrode and applied electrodes directly to the chest. The chest electrodes worked, too; they just required a larger current to pass the electricity through the ribs and chest muscles. The timing of the external impulses had to be perfect, however; stimulating the heart during the vulnerable period could cause it to fibrillate. So Zoll created algorithms to properly trigger the stimulus from an EKG tracing.
External pacing worked in human volunteers, but it was torturously painful. The electric current would cause agonizing contractions of the chest muscles and quickly blister and ulcerate the skin. Moreover, like the rest of the hospital, external pacemakers were powered by the municipal electrical grid. Power cords had to be strung along hospital corridors and even down stairwells when patients wanted to ambulate. The grid was prone to shutdowns and failure, hardly reassuring when treating a pacemaker-dependent patient with complete heart block. External pacing was therefore only a short-term therapy for heart block.
For a more durable solution, a revolutionary idea emerged: to implant a pacemaker inside the body, allowing it to deliver a stimulus directly to the heart rather than to the chest muscles. The heart has few sensory nerve endings, so intracardiac pacing would not be painful. Moreover, powered by its own battery, an implantable pacemaker could be long-lasting and more reliable.
The concept of direct cardiac pacing materialized in a familiar place: the Department of Surgery at the University of Minnesota. Walt Lillehei, the pioneer of cross-circulation, was learning that conduction block was a frequent complication of his open-heart surgeries, either with cross-circulation or, after 1954, with the heart-lung machine. Suturing a ventricular septal defect could sever conduction pathways or cause enough tissue inflammation to disturb the pathways temporarily. During a morbidity and mortality conference at the university in 1956, a physiologist suggested that directly pacing the heart through an electrode on the heart’s surface could rectify this problem. It would allow stimuli to be delivered to the heart at much lower voltage and be more dependable than external pacing of the chest wall.
Lillehei’s team took this idea to the lab in Millard Hall. They created heart block in anesthetized dogs by passing a suture around the top portion of the ventricular conduction system. As expected, the dogs’ heart rate quickly plummeted. They then stitched a wire into the outer wall of the heart, connected it to a pulse generator, and found that the heart rate picked right up.
After experiments with some fifty dogs, Lillehei used this “myocardial wire” for the first time in a human being on January 30, 1957. The six-year-old girl developed heart block during repair of a ventricular septal defect. With the wire in place and connected to a generator, the girl’s ventricular rate increased immediately from thirty to eighty-five beats per minute, and she survived the operation. Lillehei was soon using the myocardial wire whenever a patient showed signs of heart block during or after open-heart surgery. His device was the first electrical instrument left inside the human body for any extended period, and it worked beautifully. However, it too was only a temporary fix because the wire had to be brought out of the chest through a surgical incision to be hooked up to a generator, thus creating a possible site of infection. It was designed to treat short-term, postsurgical heart block, albeit more effectively than external pacing.
Like much of what Lillehei did as a surgeon, there was no precedent for the myocardial wire. There was no way of knowing up front that it would work, that it wouldn’t cause a host of complications—infection, bleeding, scarring—that putting a piece of metal inside the human body and leaving it there, tunneling a portion of it out through a break in the skin that could serve as a portal for germs, wasn’t totally ridiculous. It was impossible to know any of this without trying. But Lillehei, more than any
doctor of the twentieth century, specialized in trying the outlandish.
A long-term solution to complete heart block was needed, however. Older adults frequently develop chronic heart block because of myocardial infarction or age-related scarring and may require pacing for months, even years, to remain alive. Between 1957 and 1960, research groups from all over the world raced to design and test a fully implantable pacemaker. But in the end, Wilson Greatbatch, an unassuming electrical engineer at the University of Buffalo, was the first to succeed.
As with so many great cardiac innovations of the past century, the inspiration for Greatbatch’s invention was a mistake. In the early 1950s, Greatbatch was working on a livestock farm near Ithaca, New York, testing instruments to monitor heart rate and brain waves in sheep and goats, when he learned about heart block from two surgeons doing a summer research sabbatical there. “When they described it, I knew I could fix it,” Greatbatch later wrote. A few years later in Buffalo, Greatbatch was working with the newly invented transistor when he accidentally installed a resistor into a circuit he was testing, causing it to give off a signal that pulsed for 1.8 milliseconds, stopped for a second, and repeated—a rhythm that mimicked the human heartbeat. “I stared at the thing in disbelief and then realized this was exactly what was needed to drive a heart,” Greatbatch wrote. “For the next five years, most of the world’s pacemakers used [this circuit], just because I grabbed the wrong resistor.”
In the spring of 1958, Greatbatch visited Dr. William Chardack, chief of surgery at the Veterans Affairs Hospital in Buffalo, to explain his idea. Chardack was enthusiastic. “If you can do that, you can save ten thousand lives a year,” he told Greatbatch. So Greatbatch went back to his workshop and fashioned a prototype device out of two Texas Instruments transistors. Three weeks later, Chardack implanted it into a dog. The two men watched in awe as the tiny device took over the heartbeat. “I seriously doubt if anything I ever do will give me the elation I felt that day when my own two-cubic-inch piece of electronic design controlled a living heart,” Greatbatch wrote. From antiquity to modern times, philosophers and physicians had dreamed of taking charge of the human heartbeat. And finally it was possible, using simple circuit elements that were widely available. It was a seminal moment in the history of science.
However, Greatbatch’s device had problems. It was sealed with electrical tape, so body fluids caused it to malfunction after a few hours. “The warm moist environment of the human body proved a far more hostile environment than outer space or the bottom of the sea,” Greatbatch wrote. So he worked to cast the electronics in solid epoxy to make them more impervious, thus increasing their life span to four months. With no external funding, and splitting his time between Chardack’s crowded lab and a small workshop in the barn behind his house, Greatbatch worked on the critical problems standing in the way of permanent cardiac pacing: battery life, proper insulation, and rising stimulation thresholds requiring higher and higher current to control the heart over time. (In the process, Greatbatch invented the first long-lasting lithium battery, still in use today.) By the late summer of 1959, Greatbatch had used up his personal savings of $2,000 to handcraft fifty implantable pacemakers. Forty were tested on animals; the remainder went into humans. The first human implant took place on April 7, 1960, in a seventy-seven-year-old man with complete heart block. He survived for eighteen months. The wires were hooked up to the outer wall of the ventricle, but later, using techniques developed by Wilfred Bigelow, the Canadian surgeon who pioneered surgical hypothermia, wires were passed through veins and directly into the heart. The Chardack-Greatbatch pacemaker worked remarkably well. One of the first patients to get one was electronically paced for more than twenty years and died in her eighties.
In the fall of 1960, Greatbatch and Chardack licensed their implantable pacemaker to a small Minneapolis company called Medtronic, which had been started by Earl Bakken, an electrical engineer who worked with Lillehei. Production began almost immediately. By the end of the year, the company had orders for fifty pacemakers at $375 apiece. Greatbatch continued to work on the device, testing transistors and other components in two ovens and a workbench set up in his bedroom in upstate New York. (The U.S. Minuteman nuclear missile program subsequently adopted many of Greatbatch’s quality-control measures.) The demand for cardiac pacemakers quickly skyrocketed. Approximately 40,000 units were implanted in 1970 and about 150,000 in 1975. Today there are more than one million units in use around the world. In 1984, the National Society of Professional Engineers selected the implantable pacemaker as one of the ten most important engineering contributions to society over the preceding half century and honored Wilson Greatbatch, the humble engineer from upstate New York, as its inventor.
•
In addition to complete heart block, a deadly-slow arrhythmia, the other great problem cardiac electrophysiologists were grappling with at mid-century was ventricular fibrillation, the fast arrhythmia that was responsible for most sudden deaths across the world. At the turn of the century, Jean Louis Prévost and Frédéric Battelli, two researchers at the University of Geneva, discovered that electricity could be used not only to provoke ventricular fibrillation but to tame it as well. They were able to induce fibrillation in animals with relatively weak alternating current and then terminate it with a much larger “defibrillatory” jolt, resetting the heartbeat. Decades later, in 1947, the American surgeon Claude Beck successfully used electrical defibrillation for the first time in an operating room, on a fourteen-year-old boy at the Case Western Reserve University Hospital in Cleveland who went into cardiac arrest following a chest operation. The boy survived to be discharged from the hospital. Beck later wrote that defibrillation was a tool for saving “hearts too good to die.” He envisioned the therapy as being “at the threshold of an enormous potential to save life.”
As was the case with electronic pacing, externally applied defibrillation came first. In 1956, Harvard’s Paul Zoll, who also pioneered external pacing, performed the first successful external defibrillation in a human subject. Other scientists, most notably William Kouwenhoven, a professor of electrical engineering at Johns Hopkins, also made seminal contributions. Kouwenhoven worked on external defibrillation for decades, mainly in rats and stray dogs. By 1957, he had assembled a defibrillator in his research lab on the eleventh floor of the Johns Hopkins Hospital. That March, a forty-two-year-old man arrived in the emergency room at two o’clock in the morning complaining of indigestion. He was actually having an acute myocardial infarction, and while undressing, he collapsed in ventricular fibrillation. The admitting resident, Gottlieb Friesinger, had heard about Kouwenhoven’s defibrillator and raced upstairs to get it while an intern attempted to resuscitate the patient. Friesinger persuaded a security officer to let him into Kouwenhoven’s lab, where he picked up the hefty device, nearly two hundred pounds, and wheeled it to the ER. With one electrode at the top of the breastbone and another just below the nipple, he delivered two shocks to revive the dying man. It was the world’s first successful emergency defibrillation for cardiac arrest.
Kouwenhoven’s research produced an unusual and unexpected side benefit. In experiments on dogs in the late 1950s, Guy Knickerbocker, a graduate student in Kouwenhoven’s lab, noticed that blood pressure rose slightly when defibrillator paddles were pressed into position, even before any electrical current had been administered. Collaborating with James Jude, a surgeon, Knickerbocker showed that pressing on the chest can compress the heart and cause blood to temporarily circulate, thus increasing blood pressure. His observation set the stage for the introduction of chest compressions during cardiopulmonary resuscitation, the standard treatment used today. Within a year, this technique was being taught to firefighters and other rescue personnel. The discovery, serendipitously, benefited Knickerbocker personally. In 1963, his father underwent successful CPR during cardiac arrest after a heart attack.
External defibrillators quickly proliferated in the new cardiac care units of the 19
60s. The machines were at the ready to treat the arrhythmic disturbances of heart disease, if not the disease itself. Monitoring in these units confirmed that ventricular fibrillation was the most common cause of cardiac arrest and sudden death. In 1961, a group led by Bernard Lown at Harvard incorporated a timer to synchronize the defibrillator with an EKG to avoid delivering shocks to the heart during the vulnerable period.
But as was the case with pacemakers, external defibrillators were unwieldy, and the shocks they delivered—in the rare cases when patients were still conscious—were painful. Moreover, they relied on bystander administration, hardly infallible during an emergency. Therefore, as with pacemakers, the goal became to miniaturize, automate, and implant them inside the body.
Though several groups were involved in the invention of external defibrillation, only one, led by Michel Mirowski at Sinai Hospital in Baltimore, was responsible for the creation of the implantable defibrillator. As a Jew born and raised in Warsaw, Mirowski led a peripatetic life. In 1939, as an adolescent, he left his family and fled his country after the German invasion and occupation of Poland. (He was the only member of his family to survive the war.) He ultimately returned to Poland. After the war, he did his medical training in France. A Zionist, he eventually moved to Israel. In 1966, when he was already a practicing cardiologist, he experienced a life-changing tragedy when his close friend and mentor, Harry Heller, died of ventricular tachycardia, a malignant rhythm that is often a precursor of ventricular fibrillation. Like so many traumatized by sudden cardiac death, it became his lifelong obsession.
In 1968, Mirowski moved to the United States. As chief of the new coronary care unit at Sinai Hospital, he negotiated time to pursue his own work in the basement of the hospital’s research building. His project, conceived in Israel after Heller’s death, was to build an implantable defibrillator. Mirowski paired up with Morton Mower, another cardiologist, and together they created a blueprint for the device. Mirowski knew that a strong electrical shock was needed to terminate ventricular fibrillation. However, he believed that with external defibrillation, most of this energy was wastefully dissipated in the tissues around the heart. He wondered whether the discharge of a simple capacitor, an electronic element that stores charge, might be sufficient to terminate fibrillation if the capacitor was in direct contact with the heart. Working with engineers, Mirowski and Mower designed circuitry to detect ventricular fibrillation and trigger the charging of a capacitor by a battery. The challenges were enormous: miniaturizing the circuits, constructing electronics to ensure the delivery of appropriate shocks (while avoiding inappropriate ones that could put healthy patients into ventricular fibrillation), and assembling a generator powerful enough to deliver multiple shocks for each fibrillation episode. The pair worked alone, like Greatbatch, and like Greatbatch they used their own money to pay for experimental animals and electrical components. At one point, they stole spoons from a nearby restaurant to make the implantable electrodes. Mirowski had great focus and will. His “three laws” were these: Don’t give up. Don’t give in. And beat the bastards.
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