The Impossible Dream: How a Mechanical Heart Changed Medicine Forever

The birth of the first successful artificial heart stands among the most daring and transformative chapters in the history of medicine. It was not merely a feat of engineering but a profound redefinition of the boundary between biology and machine. When the Jarvik-7 was implanted into Barney Clark on December 2, 1982, it marked the culmination of decades of research and the beginning of a new era in cardiovascular care. Today, mechanical circulatory support is a standard therapy for end-stage heart failure, saving tens of thousands of lives worldwide each year. This article traces the full arc of that journey—from the earliest theoretical visions to the sophisticated devices now used in clinical practice—and explains why the artificial heart remains one of the most audacious scientific quests of the modern age.

The Early Pioneers: From Dream to Early Prototypes

The concept of replacing a failing human heart with a mechanical pump was first seriously entertained in the early twentieth century, but it was not until the 1950s that the necessary materials, surgical techniques, and biomedical engineering expertise converged to make the dream tangible. The central figure in this early era was Dr. Willem Kolff, a Dutch-born physician who had already built the first successful artificial kidney (the dialysis machine) during World War II. After emigrating to the United States, Kolff established an artificial organ laboratory at the Cleveland Clinic, where he recruited a team of brilliant young researchers, including Dr. Tetsuzo Akutsu from Japan.

In 1957, Kolff and Akutsu achieved a milestone that had been dismissed by many as science fiction: they implanted a total artificial heart into a dog. The device was a simple, pneumatically driven sac made of polyvinyl chloride, powered by an external compressor. The animal survived for approximately 90 minutes. Although the outcome was short-lived, it demonstrated a critical principle—that a mechanical pump could take over the function of the heart and sustain life. The experiment electrified the small community of cardiovascular researchers and sparked an international race to build a human-ready device.

The U.S. National Institutes of Health (NIH) formalized this effort in 1964 by launching the Artificial Heart Program, which provided sustained federal funding for research into both total artificial hearts and ventricular assist devices. Over the next two decades, hundreds of animal implants were performed at institutions including the Cleveland Clinic, the University of Utah, the Texas Heart Institute, and the University of Pennsylvania. Researchers experimented with a wide variety of designs: sac-type hearts, roller pumps, pusher-plate devices, and early attempts at continuous-flow pumps. Each generation brought incremental improvements in biocompatibility, durability, and hemodynamic performance.

Despite these advances, no device was considered safe enough for human use by the early 1970s. The obstacles were formidable: blood contact with synthetic surfaces triggered clotting, leading to strokes; infection at the driveline entry sites was common; and the mechanical components were prone to catastrophic failure. Many researchers grew skeptical that a truly implantable artificial heart would ever be possible. But a small group of scientists at the University of Utah, led by Dr. Robert Jarvik and Dr. Willem Kolff (who had moved to Utah in 1967), refused to abandon the goal. They designed a new device that would become the Jarvik-7. For a detailed historical account of these early efforts, see the comprehensive review from the National Institutes of Health.

The First Human Implant: Barney Clark and the Jarvik-7

The world changed on December 2, 1982. At the University of Utah Medical Center, surgeon Dr. William DeVries led a surgical team that removed the severely damaged natural heart of Barney Clark, a 61-year-old retired dentist from Washington state, and replaced it with the Jarvik-7. Clark had been in the final stages of congestive heart failure, with a life expectancy measured in days. He was not a candidate for heart transplantation because of his age and the presence of other medical conditions. The decision to proceed with the implant was made after extensive ethical review and with Clark’s fully informed consent.

The surgery itself was technically demanding but proceeded without major complications. The device began pumping immediately, and Clark was weaned from the heart-lung machine. For the first time, a human being was alive with a completely mechanical heart. The news spread across the globe instantly, and the University of Utah became the center of a media firestorm. The story of Barney Clark and the Jarvik-7 is chronicled in extensive contemporary reporting by the New York Times.

The Architecture of the Jarvik-7

The Jarvik-7 was a pneumatically powered, two-chambered total artificial heart designed to replace both ventricles. It was built from biocompatible polyurethane and consisted of two separate pumping chambers, each with an internal flexible membrane that moved back and forth to eject blood. The device was connected via two long hoses to a large external drive console that delivered pulses of compressed air. Key design features included:

  • Four mechanical tilting-disc valves that ensured unidirectional blood flow and prevented regurgitation. These were the same types of valves used in human valve replacement surgery at the time.
  • A textured Dacron surface lining the interior walls of the pumping chambers. This rough surface encouraged the deposition of a stable protein layer and eventually a neo-intimal lining, reducing the risk of clot formation compared to smooth plastic surfaces.
  • An external drive console that generated pneumatic pulses at adjustable rates and pressures. The console was large, heavy, and immobile, confining the patient to a hospital bed.
  • Separate left and right pumping chambers that could be individually controlled to balance the pulmonary and systemic circulations, mimicking the physiological output of a natural heart.

The Jarvik-7 was never intended as a permanent replacement. Dr. Jarvik and the surgical team envisioned it as a “bridge to transplantation” for patients who would die waiting for a donor heart. In Clark’s case, however, transplantation was not an option, so the device was used as what would later be called “destination therapy.”

The 112-Day Battle: Outcomes and Lessons

Barney Clark survived for 112 days after the implant, but his journey was fraught with complications. In the first week, he suffered from respiratory failure requiring a tracheostomy. He later developed infections at the driveline exit sites, which led to sepsis. Blood clots formed within the device on multiple occasions, breaking loose and traveling to his brain, causing several strokes. Mechanical failures also occurred: a valve fractured and had to be replaced, and the pneumatic drive console experienced malfunctions. Despite these setbacks, the Jarvik-7 maintained Clark’s circulation effectively, and he remained conscious and able to communicate with his family and doctors for much of his time. His death on March 23, 1983, was attributed to multisystem organ failure, a consequence of the recurrent infections and embolic events.

The case provoked intense ethical debate. Critics argued that Clark had been subjected to prolonged suffering for an experiment that had little chance of success. Supporters countered that he had volunteered for a historic endeavor that would ultimately benefit countless future patients, and that he had been fully informed of the risks. The debate continues to echo in contemporary discussions about the ethics of high-risk surgical innovation. What is beyond dispute is that the 112-day survival proved a scientific fact of enormous importance: a total artificial heart could sustain human life for an extended period. The stage was set for the next wave of innovation.

From Bridge to Destination: The Evolution After Jarvik

The Jarvik-7 experience exposed the critical weaknesses of pneumatically driven total hearts: high infection rates from the drivelines, a high incidence of thromboembolism, and the severe mobility limitations imposed by the external console. In the decades that followed, researchers pursued two parallel tracks: refining the total artificial heart concept for safer long-term use, and developing ventricular assist devices (VADs) that supported the native heart rather than replacing it entirely. Each track produced significant breakthroughs.

The SynCardia Total Artificial Heart

The most direct descendent of the Jarvik-7 is the SynCardia temporary total artificial heart. After Symbion (the company that manufactured the Jarvik-7) encountered regulatory and financial difficulties, the device was acquired and refined by a new entity, SynCardia Systems. The SynCardia TAH retained the same basic pneumatic design but benefited from decades of incremental improvements in materials, valve design, and driveline management. It received FDA approval in 2004 for use as a bridge to transplantation. A major advance came with the introduction of the Freedom portable driver, a lightweight (13.5 pound) device that allowed patients to be discharged from the hospital and live relatively normal lives while waiting for a donor heart. As of the 2020s, more than 2,000 SynCardia implants have been performed globally, with one-year survival rates exceeding 70% in bridge-to-transplant populations. The device is the most widely used total artificial heart in the world, and its success is a direct testament to the foundational work of the Jarvik team. The official SynCardia website provides detailed information on current outcomes and patient eligibility.

The AbioCor: The Quest for Full Implantability

In 2001, another landmark was achieved at the University of Louisville, where surgeons implanted the AbioCor total artificial heart. Developed by Abiomed, the AbioCor was the first fully implantable TAH, meaning it had no drivelines piercing the skin. Power was transmitted wirelessly through a transcutaneous energy transfer (TET) system, and an internal battery allowed the patient to be free from external connections for brief periods. The device was hydraulically driven, using a motorized pump to move hydraulic fluid between chambers that displaced blood. The first recipient, Robert Tools, survived 151 days. Although the AbioCor extended life and improved quality of life for some patients, it was large (it could only fit in about half of male chest cavities), and it was associated with significant risks of stroke and infection. Abiomed eventually discontinued the program, but the AbioCor demonstrated that a fully implantable TAH was technically achievable and motivated further research into wireless power and internal control systems.

The Jarvik 2000 and the Shift to Continuous-Flow VADs

Dr. Robert Jarvik did not rest after the Jarvik-7. He recognized that for most patients with heart failure, replacing only the failing left ventricle was a simpler and safer approach than total heart replacement. In the 1990s, he developed the Jarvik 2000, an axial-flow ventricular assist device that was small enough to be implanted within the chest alongside the natural heart. The Jarvik 2000 used an impeller that spun at high speeds to generate continuous blood flow, eliminating the need for a sac and valves. This design was radically simpler than the Jarvik-7 and had a much lower risk of thrombosis and mechanical failure. First implanted in 2000, the Jarvik 2000 became a prototype for the modern generation of continuous-flow LVADs. Patients with the device could be discharged home, return to work, and in some cases, even participate in recreational sports. The development of downstream continuous-flow VADs such as the HeartMate II and HeartMate 3 has built directly on this concept.

The Modern Era: Continuous-Flow Dominance and the Role of Total Hearts

As of the mid-2020s, the landscape of mechanical circulatory support is dominated by continuous-flow left ventricular assist devices (LVADs). These pumps are smaller, quieter, more durable, and significantly less prone to complications than their pulsatile predecessors. The HeartMate 3 (manufactured by Abbott) is the current gold standard. It uses a centrifugal rotor that is magnetically levitated, eliminating contact between moving parts and thereby reducing friction, heat generation, and blood cell damage (hemolysis). Clinical trials have shown one-year survival rates exceeding 80% for patients receiving a HeartMate 3, with low rates of stroke and pump thrombosis. Patients with these devices can live active, high-quality lives for years.

Total artificial hearts remain in use for a smaller subset of patients: those with severe biventricular failure that cannot be managed with LVADs alone, those with complex congenital heart disease, and those who have developed complications from VADs. The SynCardia TAH is currently the only FDA-approved total artificial heart in the United States. However, new designs are in the pipeline. The BiVACOR total artificial heart, developed by Dr. Daniel Timms, uses a single magnetically levitated rotor that can produce either continuous or pulsatile flow. It is much smaller than the SynCardia device and has no valves or moving parts in contact with blood. Human clinical trials for the BiVACOR began in 2024, with the first implant performed at the Texas Heart Institute. For a broader perspective on these technologies, the Mayo Clinic’s overview of ventricular assist devices offers an excellent patient-oriented summary.

Destination Therapy: A Permanent Solution

One of the most important conceptual shifts since the Jarvik-7 era is the emergence of destination therapy (DT). Originally, mechanical circulatory support devices were used almost exclusively as a bridge to transplantation. But because the supply of donor hearts has never come close to meeting demand, and because many patients are not candidates for transplantation due to age or comorbidities, the idea of using these devices as a permanent, lifelong solution gained traction. The landmark REMATCH trial, published in 2001, showed that patients with end-stage heart failure who received a HeartMate I LVAD as destination therapy had significantly better survival and quality of life than those treated with medical management alone. Since then, destination therapy has become the most common indication for LVAD implantation in the United States. Data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) show that over 50% of all LVAD implants are now destination therapy, with steadily improving outcomes over time.

The Next Frontier: Biohybrid Hearts, Soft Robotics, and AI

Despite the remarkable progress made since 1982, the perfect artificial heart—one that matches the durability, biocompatibility, and autoregulatory ability of the natural heart—remains an elusive goal. Current devices still carry risks of infection, stroke, bleeding (due to required anticoagulation), and pump malfunction. Researchers are pursuing several transformative approaches to overcome these limitations:

  • Biohybrid artificial hearts: These devices combine synthetic structural components with living cardiac cells or tissue. The goal is to create a heart that is biologically integrated and can adapt to the body’s metabolic demands, perhaps even growing with a pediatric patient. Scientists at the University of Minnesota and the University of Pittsburgh are using 3D bioprinting to create scaffolds seeded with induced pluripotent stem cell-derived cardiomyocytes. While a fully functional biohybrid heart remains years away, small patches of living heart tissue have been successfully implanted in animal models and shown to integrate with surrounding muscle.
  • Soft robotics and biomimetic actuation: The natural heart is a soft, compliant organ that contracts in a twisting motion. Current artificial hearts use rigid pumps that cannot replicate this subtle biomechanics. Soft robotic actuators, made from materials such as silicone elastomers and driven by pneumatic or hydraulic pressure, can mimic the natural contraction pattern more closely. Researchers at Harvard and the University of Tokyo have developed soft robotic sleeves that wrap around a failing heart and assist its contractions, and a fully soft total artificial heart was tested in a preclinical model in 2023. Although still experimental, these designs promise reduced blood trauma and better hemodynamic performance.
  • Wireless power and internal energy storage: The driveline remains the Achilles’ heel of many current devices, because it provides a portal for infection. Advances in transcutaneous energy transfer (TET) and high-energy-density batteries may soon make it possible to eliminate all external connections. A fully implantable heart with a TET system and an internal battery that could be recharged wirelessly through a vest or a pad would drastically reduce infection risk and improve patient quality of life.
  • Artificial intelligence and individualized control: Future devices will likely incorporate sensors that measure blood pressure, flow rate, oxygen saturation, and patient activity level. An onboard AI algorithm would continuously adjust pump speed and pulsatility to maintain optimal perfusion across varying physiological states—rest, exercise, sleep, stress. This kind of intelligent autoregulation is already being tested in LVAD controllers and represents the next logical step in making mechanical hearts truly “smart.”

For a deep dive into the science of biohybrid heart technologies, readers should consult the recent review article in Nature Reviews Cardiology.

Legacy and Unfinished Business

The story of the first successful artificial heart is not a simple narrative of triumphant progress. It is a story of audacious ambition, profound ethical complexity, and incremental, painstaking engineering. Barney Clark lived only 112 days, but his willingness to undergo the first implant changed the course of medicine. His legacy is visible in every patient who waits for a transplant while supported by a SynCardia heart, and in every patient who returns to an active life with a HeartMate 3 LVAD. The Jarvik-7 was not the end of the journey but the beginning of a sustained multinational effort that has saved hundreds of thousands of lives and transformed heart failure from a death sentence into a manageable chronic condition for many.

Yet the work is far from finished. The ideal artificial heart—one that is fully implantable, biologically integrated, infection-proof, and capable of lifelong autoregulated function—has not yet been built. The next generation of devices, whether they are biohybrid constructs, soft robotic pumps, or magnetically levitated continuous-flow hearts, will have to solve these remaining problems. The engineers and surgeons who take up that challenge stand on the shoulders of Kolff, Akutsu, Jarvik, DeVries, and Clark. Their quest, like any quest to perfect the human heart, is both a scientific and a profoundly human undertaking.