When Were Pacemakers Invented? A Look at Their History

The cardiac pacemaker as we know it traces back to October 8, 1958, when Swedish surgeon Åke Senning implanted a fully internal device into a patient named Arne Larsson at the Karolinska Hospital in Stockholm. But the story begins decades earlier, with crude external machines that could jolt a stopped heart back into rhythm. The path from those room-sized contraptions to today’s leadless devices, small enough to be threaded through a vein, is one of the more dramatic arcs in medical engineering.

Early Experiments in the 1920s and 1930s

Before anyone dreamed of putting an electrical pacer inside the human body, physicians were experimenting with external stimulation to restart failing hearts. In 1928, Australian anesthesiologist Mark Lidwill reported using a portable device to revive a stillborn infant by delivering electrical impulses through a needle electrode inserted into the heart. Around the same time, American physician Albert Hyman built a hand-cranked machine he called an “artificial pacemaker,” coining the term that stuck. Hyman’s device was heavy and unreliable, and the medical establishment met it with skepticism. Some critics accused him of interfering with the will of God. Neither Lidwill’s nor Hyman’s work led immediately to clinical adoption, but they demonstrated the core principle: the heart’s rhythm could be restored with precisely timed electrical pulses.¹

External Pacing in the 1950s

The first clinically successful pacemaker arrived in 1952, designed by cardiologist Paul Zoll at Beth Israel Hospital in Boston. Zoll’s machine delivered electrical shocks through metal plates pressed against the patient’s chest. It worked, keeping patients with life-threatening heart block alive when nothing else could. The catch was everything else about the experience. The device was the size of a small cabinet. It ran on alternating current from a wall outlet, meaning patients were tethered to an electrical cord. The chest-wall shocks were painful enough to leave burns on the skin, and the patient had to remain essentially immobile. Despite these drawbacks, Zoll proved that external pacing could save lives, and the race began to miniaturize the technology and move it inside the body.¹

October 1958 and the First Implant

The breakthrough came on October 8, 1958, at the Karolinska Hospital in Solna, Sweden. Engineer Rune Elmqvist had designed a small, self-contained pulse generator encased in epoxy resin, and surgeon Åke Senning implanted it into Arne Larsson, a 43-year-old man suffering from complete heart block who had been experiencing repeated bouts of cardiac arrest.² The device was powered by rechargeable nickel-cadmium cells and was roughly the size of a hockey puck. It failed within hours. A second unit was implanted the next day and lasted a few weeks before it, too, gave out. Larsson would go on to receive more than 20 pacemakers over his lifetime and lived until 2001, dying at 86 of an unrelated illness. His survival became a powerful testament to the concept, even if the early hardware was far from dependable.

The American Chapter

Two years after the Swedish implant, the technology crossed the Atlantic in a more durable form. On June 6, 1960, in Buffalo, New York, surgeon William Chardack implanted a pacemaker designed by electrical engineer Wilson Greatbatch into a 77-year-old man with complete heart block. The patient survived an additional 18 months.³ Greatbatch’s design used a different circuit approach and proved more reliable than the early Elmqvist devices. It was the beginning of a commercial pacemaker industry. Greatbatch went on to make another contribution that arguably mattered even more than the generator itself: the lithium iodine battery.

Solving the Battery Problem

For the first decade of implantable pacing, batteries were the weakest link. The earliest implants used nickel-cadmium rechargeable cells that needed frequent recharging through the skin, which was both inconvenient and infection-prone. The next generation switched to zinc-mercury batteries, which lasted over two years but still required surgical replacement at uncomfortably short intervals.⁴ Patients in the 1960s might undergo surgery every couple of years just to swap out a dead battery, each operation carrying its own risks of infection and complications.

In 1972, Greatbatch and his team developed the lithium iodine battery, and pacemaker engineering changed overnight. Lithium iodine cells delivered a stable voltage over long periods and lasted roughly ten years. That single innovation cut the number of replacement surgeries dramatically and made the pacemaker a far more practical long-term therapy. Lithium iodine remains the power source in many pacemakers today, more than fifty years later.⁴

How Leads Improved Over the Decades

A pacemaker is only as good as the wires connecting it to the heart. These leads carry the electrical impulse from the generator to the cardiac tissue, and early designs had a frustrating tendency to slip out of position. The original “wedge tip” leads were placed against the inner wall of the heart and held in place partly by friction. Dislodgement rates were high, and many patients needed repeat surgery to reposition a wandering lead.

The introduction of “tined” leads in the late 1970s and 1980s changed the picture significantly. Tined leads had small flexible prongs near the tip that snagged in the heart’s trabecular tissue, holding the electrode in place while scar tissue formed around it. A comparison of over 800 leads found that tined leads dislodged far less often than wedge-tip designs, and the rate of repeat operations dropped sharply.⁵ Meanwhile, the insulation materials evolved from early silicone rubber to polyurethane and back again, each generation trying to balance flexibility, durability, and biocompatibility. Both materials showed similar overall complication rates in clinical use, but for different reasons: polyurethane was thinner and easier to handle but could degrade over time, while silicone was bulkier but chemically more stable.

Active-fixation leads followed, using a small corkscrew mechanism at the tip to screw into the heart wall. These gave surgeons more flexibility in where they placed the electrode, which mattered as pacing strategies grew more sophisticated and doctors needed to target specific locations inside the heart’s chambers.

Making Pacemakers Safe for MRI

For decades after pacemakers became routine, one of the most common frustrations for patients was being told they could not have an MRI. Magnetic resonance imaging uses powerful magnetic fields and radiofrequency pulses that could interfere with a pacemaker in dangerous ways: the magnetic field could move ferromagnetic components inside the device, radiofrequency energy could heat up the leads and burn the heart tissue at the electrode tip, and the changing magnetic gradients could fool the pacemaker’s sensing circuits into delivering shocks at the wrong time or withholding needed pacing.

Engineers tackled each of these problems individually. Ferromagnetic content was minimized. The reed switches that older devices used as magnetic sensors were modified or replaced. Leads were redesigned to reduce the electrical currents that MRI fields could induce. Filters and shielding were added to the circuitry to block unwanted electromagnetic interference.⁶ The result was a new generation of “MR-conditional” pacemakers, cleared for use under specific MRI conditions.⁷ These devices are not entirely MRI-proof. They are approved for certain field strengths, certain body regions, and certain scan durations. But for a patient who needs both a pacemaker and a brain or knee MRI, the improvement was transformative.

Going Leadless

The most striking change in pacemaker design in recent years has been the elimination of leads entirely. Leadless pacemakers are self-contained capsules, roughly the size of a large vitamin pill, that are delivered to the heart through a catheter threaded up from the femoral vein in the leg. The device anchors itself directly to the inner wall of the right ventricle and paces from there, with no wires, no chest incision, and no subcutaneous generator pocket.

A large prospective study of one such leadless system found it was successfully implanted in over 99% of patients. Its safety profile was comparable to that of conventional transvenous pacemakers, and pacing thresholds remained low and stable over time.⁸ By eliminating the pocket under the skin where the generator traditionally sits, leadless devices avoid one of the most common complications of conventional pacing: pocket infections. They also eliminate lead fractures and insulation breaks, which historically accounted for a significant share of repeat surgeries. The trade-off is that leadless devices currently pace only the right ventricle, which limits their use to patients who need single-chamber pacing. Patients requiring dual-chamber or biventricular pacing still need a conventional system, though multi-chamber leadless designs are in development.

What Pacemakers Mean for Survival

Before pacemakers, complete heart block was often a death sentence. The heart would beat too slowly to sustain consciousness, patients would faint repeatedly, and many died. Today, the survival picture is dramatically different, though it depends heavily on what else is going on with the patient’s heart.

For younger adults without structural heart disease who receive a pacemaker, long-term survival is essentially the same as that of the general population. A study tracking young pacemaker recipients over 30 years found that after an initial high-risk period in the first six months, roughly 70% of patients survived beyond 20 years. Patients whose only problem was an electrical conduction issue had outcomes indistinguishable from their peers.⁹

In older adults, the story is more nuanced. Among patients 65 to 79 years old who had isolated heart block and no other cardiac disease, survival after pacemaker implantation was comparable to the general population. But for patients 80 and older, or for those with coexisting heart failure or chronic lung disease, survival fell below population norms. The pacemaker fixed the rhythm problem but could not fix everything else.¹⁰

The reason for pacing also matters. A ten-year follow-up study found that patients paced for sick sinus syndrome had survival rates closely matching the general population. Patients with complete heart block did somewhat worse, and patients with atrial fibrillation accompanied by slow heart rates had the largest gap between their survival and that of age-matched controls.¹¹ In other words, the pacemaker itself works reliably. What determines long-term outcomes is the overall health of the heart and body it is pacing.

Pacing in Children

Children present unique challenges for pacemaker therapy. Their bodies are still growing, which means a lead implanted in a toddler’s heart needs to accommodate years of physical development. The veins through which leads are threaded may be too small in very young or very small patients, and some children with congenital heart defects have unusual cardiac anatomy that makes standard lead placement impossible.

When transvenous leads can be placed in children, outcomes tend to be good. Transvenous pacing in pediatric patients has been associated with lower initial pacing thresholds and fewer lead-related complications compared with epicardial leads, which are sewn directly onto the outside of the heart during open-chest surgery.¹² But epicardial leads remain necessary for children who are too small for a transvenous approach or who have complex anatomy from congenital heart repair. In those cases, steroid-eluting leads can reduce the scarring and threshold increases that have historically plagued epicardial pacing.

A broader concern is that children who receive pacemakers will live with them for decades, likely needing multiple generator replacements, lead revisions, and hardware upgrades over a lifetime. The pacemaker community has acknowledged that pediatric patients represent a small fraction of overall device volume but carry unique long-term needs that device design has not always adequately addressed.¹³

Pacemakers for Animals

Humans are not the only species to benefit from cardiac pacing. Dogs, in particular, develop many of the same heart rhythm disorders that humans do, including sick sinus syndrome and complete heart block. Veterinary cardiologists began adapting human pacemaker technology for dogs in the 1980s, and the procedure has become well established at referral hospitals.

Early veterinary pacing used epicardial leads placed during open-chest surgery, but transvenous implantation (threading the lead through a vein, just as in humans) proved less traumatic and became the preferred approach. A study of 40 dogs receiving permanent transvenous pacemakers found the procedure feasible and effective, though complications including lead dislodgement and infection required careful surgical technique.¹⁴ A later, larger review of 105 dogs confirmed that transvenous pacing had become a routine option in veterinary cardiology.¹⁵ Most veterinary pacemakers are repurposed human devices, often units that have been recalled for minor issues but remain perfectly functional for a dog whose expected lifespan with the device is shorter than a human’s.

The Psychological Side of Living With a Pacemaker

Most conversation about pacemakers centers on physical survival, but the psychological dimension deserves attention, especially for younger recipients. A person who gets a pacemaker at 25 faces a different emotional landscape than someone who gets one at 75. The device can feel like a constant reminder of vulnerability, and adjusting to the idea that your heartbeat depends on a machine is not trivial.

A large population-based study of young adults who received cardiac implantable electronic devices, including both pacemakers and defibrillators, found that these recipients had a meaningfully higher risk of being diagnosed with a mental health disorder compared with matched peers who did not receive a device. The elevated risk was most pronounced in the first two years after implantation, but it persisted beyond that window as well.¹⁶ The findings support the case for psychological screening and support as part of routine follow-up, particularly for younger patients who may struggle with body image, activity restrictions, or anxiety about device malfunction.

Cybersecurity and Connected Devices

Modern pacemakers are wireless computers. They can be interrogated remotely, transmit stored data through radiofrequency or Bluetooth, and even send information to hospital monitoring systems via cloud-based platforms.¹⁷ This connectivity is medically valuable. It allows doctors to monitor battery status, detect abnormal rhythms, and adjust pacing settings without requiring the patient to come to the clinic. But it also creates a potential attack surface.

The possibility that a hacker could compromise a pacemaker captured public attention after security researchers demonstrated theoretical vulnerabilities in some commercial devices. In 2017, the U.S. Food and Drug Administration issued its first recall related to cybersecurity concerns, affecting nearly half a million pacemakers that were potentially vulnerable to unauthorized access. The recall involved a firmware update rather than physical device replacement, and no actual patient harm was ever reported. Still, the episode forced the medical device industry to confront the reality that cardiac implants are now networked devices operating in the same threat landscape as any other connected technology.¹⁸

The practical risk to individual patients remains very low. Exploiting a pacemaker’s wireless communication requires specialized equipment, close physical proximity, and specific knowledge of the device’s protocols. The scenario of a remote hacker reprogramming someone’s pacemaker from across the world, a staple of television thrillers, is not currently realistic. But as devices become more connected and as remote monitoring becomes the standard of care, the cybersecurity question is not going away. Manufacturers now build encryption and authentication into their communication protocols, and regulatory agencies have begun requiring cybersecurity assessments as part of the device approval process.