Understanding the Body Electric
In the early hours of Independence Day, 2018, I found myself awake. I put it down to jet lag: I’d just returned from South Africa, where my wife—like me, a physician—and I were working with a medical charity. I decided to get up, and drank a cup of strong coffee. Within minutes, my heart was racing. I attributed this to the caffeine, but my heart rate went on rapidly accelerating. I counted beats on my watch: a hundred and eighty a minute, three times my resting rate. My chest tightened and my breathing became labored. I tried to be calm, telling myself no, it wasn’t a heart attack, merely the exhaustion of the trip and the effect of the coffee. But the symptoms were getting worse, and I broke out in a sweat. I woke my wife, who took my pulse and called an ambulance. As I lay in the ambulance, the siren blaring above me, I prayed that I would not die before making it to the emergency room.
The first days of July are said to be a perilous time to be in the hospital, because that’s when new residents begin their training. But, despite the early hour, there was a senior E.R. doctor in attendance, who quickly instructed the medical team to place intravenous catheters in my arms, take blood for testing, strap oxygen prongs over my nostrils, and perform an electrocardiogram. She said the problem appeared to be something called an atrioventricular nodal reëntrant tachycardia. I knew what that meant. Our heartbeat starts with an electrical impulse originating in the atria, the upper chambers of the heart, and then passing to the ventricles, causing them to contract. In a normal heart, there is a delay before the next heartbeat starts; in my heart, electrical impulses were circling back immediately via a rogue pathway. My ventricles were receiving constant signals to contract, giving scant time for blood to enter them and be pumped out to my tissues.
Despite this, my blood pressure hadn’t yet plummeted to an alarming level. So the first attempt to slow my heart involved having me clench my abdominal muscles, in a so-called Valsalva maneuver, which can help control irregular heartbeats by stimulating the vagus nerve. But several tries made no difference, and my breathing was becoming more labored. The attending physician then explained that she would give me, via my I.V., a dose of adenosine, a drug that arrests the flow of electrical signals in the heart. My heart would completely stop beating. Hopefully, she said, it would re-start on its own, at a normal pace. Of course, the adenosine might fail to work. She didn’t elaborate, but I knew: the next step would be to try to reboot my heart with electroshock paddles.
One dose of adenosine did nothing. But shortly after a second dose the cardiac monitor suddenly fell silent, and I glanced at the display: a flat line. My heart had stopped. I had an eerie sense of doom, a visceral feeling that something awful would happen. But then there was a kind of thud, as if I had been kicked in the chest. My heart started to beat—slowly, forcefully. Within a few minutes, the rate and rhythm returned to normal. The electrically driven pump in my chest was again supplying blood to my body.
Timothy J. Jorgensen, a professor of radiation medicine at Georgetown University, writes in his new book, “Spark” (Princeton), that “life is nothing if not electrical.” In our daily lives, seeing lightning in the sky or plugging our appliances into wall sockets, we tend to neglect this fact. Jorgensen’s aim, in this chatty, wide-ranging tour of electricity’s role in biology and medicine, is to show us that every experience we have of our selves—from the senses of sight, smell, and sound to our movements and our thoughts—depends on electrical impulses.
He starts with amber, the material with which humans probably first attempted to harness electricity for medical uses. Amber is the fossilized resin of prehistoric trees; when rubbed, it becomes charged with static electricity. It can attract small bits of matter, such as fluff, and emit shocks, and these properties made it seem magical. Amber pendants have been found dating back to 12,000 B.C., and Jorgensen writes that such jewelry would have been valued for much more than its beauty. In the era of recorded history, accounts of amber’s use abound. The ancient Greeks massaged the ailing with it, believing, Jorgensen writes, that its “attractive forces would pull the pain out of their bodies,” and it is the Greek word for amber—elektron—that gives us an entire vocabulary for electrical properties. In first-century Rome, Pliny the Elder wrote that wearing amber around the neck could prevent throat diseases and even mental illness. The Romans also used non-static electricity from torpedo fish, a name for various species of electric ray, to deliver shocks to patients with maladies including headaches and hemorrhoids.
As late as the sixteenth century, the eminent Swiss physician Paracelsus called amber “a noble medicine for the head, stomach, intestines and other sinews complaints.” Not long afterward, the English scientist William Gilbert found that other substances, such as wax and glass, could generate charge if you rubbed them, and a German named Otto von Guericke created a crude electrostatic generator. But there was no reliable way of studying electricity until the invention of the Leyden jar, in 1745. (The jar takes its name from the city where a Dutch scientist developed it, though a German scientist achieved the same breakthrough independently around the same time.) The Leyden jar made it possible to accumulate charge from static electricity and then release it as electric current, and Jorgensen does not skimp on relating the bizarre experiments that ensued. In 1747, a French cleric named Jean-Antoine Nollet demonstrated the effect of electricity on the human body for King Louis XV:
For his next experiment, Nollet outdid himself, performing the same procedure with a chain of seven hundred Carthusian monks.
The discovery that electricity not only shocks the body but is part of what powers it came in the seventeen-eighties, when the Italian scientist Luigi Galvani conducted a series of experiments in which electric current produced movement in severed legs of frogs. Galvani attributed this discovery to what he called “animal electricity,” and for a while the study of such phenomena was known as galvanism. (Meanwhile, a sometime rival of Galvani’s, Alessandro Volta, invented the battery, giving his name to the volt.) Perhaps the most famous galvanic demonstration was conducted by Galvani’s nephew Giovanni Aldini, in January, 1803, in London. In front of an audience, he applied electrodes to the corpse of a man, George Foster, who had just been hanged at Newgate Prison for the murder of his wife and child. Jorgensen quotes a report from the Newgate Calendar, a popular publication that relayed grisly details of executions:
Some of the onlookers thought that Aldini was trying to bring Foster back to life, Jorgensen writes. He goes on to note that Aldini’s work drew the interest of the English writer and political philosopher William Godwin, who knew many electrical researchers. Godwin was the father of Mary Shelley, the author of “Frankenstein” (1818), which eventually gave us the image of Boris Karloff as the monster with electrodes sticking out from his neck. That image is pure Hollywood invention—Shelley’s monster doesn’t run on electricity—but the book mentions galvanism elsewhere and it is likely that the popular, bastardized version of the tale brings out something latent in the original.
As interest in electricity spread, there was a medical craze for electrical treatments, to address anything from headaches to bad thoughts or sexual difficulties. Jorgensen tries out the Toepler Influence Machine, a device dating from around 1900, not long before the Pure Food and Drug Act of 1906 brought a colorful era of electro-quackery to an end. The machine generates electricity with a set of spinning glass disks, operated by a hand crank, to produce what was termed “static breeze” therapy. The electrotherapist operating the machine gauges the voltage by moving two brass balls closer together as sparks fly between them. Then, with the flip of a switch, the electricity is directed to Jorgensen’s head:
It certainly sounds more pleasant than the devices described by Dr. William Harvey King, in his 1901 textbook, “Electricity in Medicine and Surgery.” King recommended treating gynecological disorders by placing an electrode in the vagina and one in the rectum and then delivering a jolt of electricity. For men with urogenital complaints, he advised inserting a slender electrode up the penis, with a second electrode in the rectum or on the testicles. If administering current to swaying testicles proved a challenge, King offered a Rube Goldberg approach, with the testicles dunked into a gravy boat filled with saline solution, which was then electrified via a copper plate.
Don’t try this at home. But there were plenty of electrotherapy devices designed for home use and mailed directly—and confidentially—to consumers. Pulvermacher’s Electric Belt, for example, was worn around the waist, with batteries providing a steady electric current to the skin. A pouch attached to the front of the belt held the testicles, like a jockstrap. This allegedly enhanced “sexual vitality,” which, Jorgensen explains, was a euphemism for treating erectile dysfunction.
Electric shocks more often bring death than enhance vitality, and people naturally feared lightning bolts hurled by any number of gods—Greek, Nordic, Hindu, Maori—long before they had any notion of electricity. Some medieval bells bear the Latin inscription Fulgura frango (“I break the lightning”), a testament to a belief that ringing church bells could offer protection against lightning. Of course, the unintended consequence was that bell ringers ended up in harm’s way. In France, between 1753 and 1786, more than a hundred bell ringers died of electrocution.
Why are some people injured or killed by lightning and others not? Jorgensen offers an educational vignette. While on a guided camping trip in the Blue Ridge Mountains in North Carolina, he was caught in a lightning storm. The guide made the group “stand on our backpacks in a crouched fetal position, legs held tightly together, with our heads down and our rain ponchos draped over ourselves.” Deaths from lightning occur in various ways—a direct strike, say, or a current from a strike nearby that flows through the ground and up into the body. Crouching down while standing on a backpack made of a nonconductive material lessens both kinds of risk.
The amperage needed to kill a person is surprisingly small. A current of as little as 0.01 amps can disrupt the electrical signals flowing from our nerves to the muscles of the chest and diaphragm, causing asphyxiation. Amperage ten times higher can stop the heart outright. What makes lightning seem “so capricious,” as Jorgensen puts it, is that some people are killed by low amperage while others survive direct strikes. The reason is a phenomenon called flashover, in which electric current flows over the surface of the body and largely bypasses the internal organs. Flashover occurs when the surface of the body is more conductive than the inside—for instance, if the skin is covered in sweat. The path that the current takes is crucial. A Danish study of electrocution deaths found that the current passed through the victim’s heart in seventy-eight per cent of cases. Furthermore, in eighty-one per cent of the victims there was no observable change to the pathology of the internal organs; in other words, death occurred not because any tissue was destroyed but because the current had interfered with the normal electrical function of the heart’s cardiac cells, nodal tissues, and conduction tracts.
With higher currents, tissue damage does occur, and the grimmest chapter in Jorgensen’s book deals with electrocution as a means of execution. The electric chair was the brainchild of Alfred P. Southwick, a dentist in Buffalo, who, one day in 1881, happened to see a drunk man stumble and grab an electrical generator. Southwick ran to the man, but the man was dead. The speed of death made him think that electricity could provide a quicker, less painful end than hanging. He based the design for an electric chair on the chair that his dental patients sat in. After Southwick had experimented with a variety of stray animals, a state commission assessed thirty-four methods of execution and decided that electrocution was the most humane. The reality has proved otherwise, and the first use of the electric chair, in 1890, gave a preview of many ugly scenes in the following century. William Kemmler, a businessman convicted of killing his girlfriend with a hatchet, was executed at New York’s Auburn Prison. A report in the New York Herald described the condemned man thrashing about for minutes, “until the room was filled with the odor of burning flesh and strong men fainted and fell like logs upon the floor.”
In the mid-nineteenth century, a schoolboy in northern Spain named Santiago Ramón y Cajal saw a local priest who’d been lethally struck by lightning while ringing his church’s bell. Years later, after Ramón y Cajal had become known as the father of neuroscience, an achievement that won him a Nobel Prize, he recalled the event in his autobiography:
Jorgensen relates that Ramón y Cajal regarded this incident as a watershed in his life and speculates that his great scientific achievements—deciphering the basic structure of the nervous system and discovering the neuron—may have their origin in a “transformative” encounter with lightning.
Ramón y Cajal’s establishment of the neuron as the fundamental unit of the nervous system led to decades of research investigating how it works; he found that neurons propagate electrical impulses that are controlled by the passage of ions, specifically sodium or potassium. Jorgensen provides an elegant description of the process and of recent attempts to exploit this knowledge by developing high-tech devices to compensate for sensory deficits: cochlear implants for deafness, electrodes in the retina or in the visual cortex of the brain for blindness.
He relates the case of a woman, Melissa Loomis, whose right forearm was amputated after an infection from a raccoon bite. Each year, a million or so people across the world undergo an amputation, but Loomis was comparatively fortunate, receiving access not merely to an artificial limb but to a neuroprosthesis—a device that links the human nervous system to an electronic mechanism. This kind of brain-machine interface captures nerve signals from the brain and translates them into electrical signals that are relayed to a computer-controlled electronic device. The translation is possible because nerve signals, like digital ones, are binary.
When healthy, our nerves conduct electricity in a tightly controlled way, in order to transmit information to all parts of the body. In this sense, illness can sometimes be synonymous with uncontrolled electricity. Jorgensen describes epilepsy, for instance, as being like “an electrical storm in the brain.” Recent research suggests that migraines, too, may have a genesis resembling a seizure, with electrical activity in the brain stem releasing proteins that trigger pain. (Anti-epileptic medications such as topiramate are used to prevent migraines.)
Shocking the brain with electricity under highly controlled circumstances can be effective in treating major depressive disorders, even though the precise mechanism isn’t fully understood. A more selective and recently developed neurological application of electricity is deep brain stimulation, or DBS, which is used to treat Parkinson’s disease and other motor disorders. Electrodes are implanted in the area of the brain to be electrically stimulated and wired up to a controller housed in the chest.
DBS is sometimes described as a pacemaker for the brain. Electrical stimulation of the heart has a longer history, the first pacemaker having been implanted in 1958. An electrode is threaded inside the heart which gives small shocks at a rate of about sixty per minute, in order to stimulate the muscle to pump normally. Jorgensen notes that the technology owes its success largely to the invention of a commercially viable transistor, in 1948, which made possible the miniaturization of electronics. Today, some three million Americans are estimated to have a cardiac pacemaker, and the device has become a model for a newer invention, the “breathing pacemaker,” to treat sleep apnea. “When breathing stops, it sends an electrical impulse to an electrode in the throat that shocks the relaxed tissues into contracting, thus reopening the airway,” Jorgensen writes.
In my case, there would have to have been a serious complication during treatment for a pacemaker to be necessary. Eventually, I was discharged from the emergency room with a beta-blocker prescription, to suppress the runaway electricity in my heart. But the side effects proved intolerable; even at low doses, my heart rate slowed so much that I could not climb a flight of stairs without stopping and gasping for air.
I consulted a cardiologist at my own hospital, Peter Zimetbaum, who is an expert in arrhythmias, and he performed an ablation to eradicate the errant pathway. Zimetbaum threaded catheters into the right and left femoral vessels in my groin and up into my heart. He injected small doses of isoproterenol, an adrenaline-like drug, which artificially induced the tachycardia that had landed me in the hospital. Then he mapped the pathways conducting electricity in my heart—the one that would carry normal impulses and the aberrant one that caused the heartbeat of a hundred and eighty. After he pinpointed the aberration, he destroyed it with heat from high-frequency radio waves. I was awake throughout the procedure, with just low doses of a painkiller, so that I could report whether what I experienced recapitulated that July morning.
After Zimetbaum had finished performing the ablation, he tried to trigger my tachycardia again, but my heart stayed steady. Electricity gone awry could have ended my life. Electricity in expert hands identified the defect in my heart and eliminated it. Now I was again a healthy body electric. ♦
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