The SynCardia Total Artificial Heart is the only complete heart replacement device that has received FDA approval, and it has been implanted in well over a thousand patients worldwide. Unlike ventricular assist devices that help a failing heart pump, the SynCardia replaces the heart entirely: both ventricles and all four native valves are removed and substituted with a pneumatic pump that takes over the full job of circulating blood. Its approved use is as a bridge to transplantation, meaning it keeps patients alive while they wait for a donor heart, and in landmark trials it roughly doubled survival to transplant compared with medical management alone. But the reality of living with one, from the external air compressor to the risk of stroke and infection, is more complex than that headline suggests.
From the Jarvik 7 to SynCardia
The device has roots stretching back decades. It descends from the Jarvik 7, the artificial heart that made headlines in the 1980s. The original manufacturer, Symbion, stopped production in 1990 after running afoul of FDA requirements. A new company called MedForte Research acquired the rights and partnered with the University Medical Center in Tucson, Arizona, eventually forming the CardioWest organization. The Jarvik 7 was renamed the CardioWest Total Artificial Heart in 1991 and received FDA approval for bridge-to-transplant use in 2004. Several years after that, in 2010, the device was rebranded again as the SynCardia temporary Total Artificial Heart, the name it carries today.1PubMed Central. Evolution of Artificial Hearts: An Overview and History – Section: Review of Literature and Discussion Through all the name changes, the core pneumatic design has remained recognizably the same, refined rather than reinvented over the years.
How the Device Works
The SynCardia TAH is a pulsatile pump, meaning it generates a beat-by-beat flow of blood rather than the continuous stream produced by newer rotary devices. It sits inside the chest cavity where the native ventricles used to be, connecting to the remaining atrial cuffs above and to the great arteries (the aorta and pulmonary artery) below. Compressed air pulses are delivered through drivelines that exit the skin and connect to an external driver console. Each air pulse inflates a diaphragm inside the device, pushing blood out; when the air is released, the chamber refills passively as blood flows in from the atria.
The diaphragm itself is an engineering detail worth noting. Rather than a single membrane, it consists of four independent layers made of a segmented polyurethane, each separated and lubricated by fine graphite particles. This stack of membranes undergoes over 50 million inflation-deflation cycles per year. The multilayer design serves a safety purpose: if one membrane tears, the remaining layers prevent air from contacting blood directly, which would be life-threatening.2PubMed Central. The Syncardia total artificial heart: in vivo, in vitro, and computational modeling studies – Section: 2. Construct and mechanism of action of the TAH
One of the device’s more appealing physiological traits is that it responds to the body’s needs in a way that loosely resembles a natural heart. When more blood returns to the device (higher preload), it pumps out more. This self-regulating behavior, tested extensively in laboratory simulations, means the device can adapt to changes in a patient’s activity level or fluid status without needing constant manual adjustment.3PubMed Central. Physiological Characterization of the SynCardia Total Artificial Heart in a Mock Circulation System – Section: Conclusion That said, the degree of adaptation has real limits, as exercise testing reveals.
Two Sizes and Virtual Fitting
For most of its history, the SynCardia TAH came in only one size: a 70 cc ventricle. That worked well for larger adults, but it physically could not fit in the chest cavities of smaller adults, most women, and adolescents. SynCardia addressed this by developing a 50 cc version. Early worldwide experience with the smaller device showed that about two-thirds of the first 28 recipients were female, and four were 21 or younger. The smallest patient by body surface area was 1.35 square meters, and the device was designed to potentially accommodate patients even smaller than that.4PubMed. The 50/50 cc Total Artificial Heart Trial: Extending the Benefits of the Total Artificial Heart to Underserved Populations
Choosing between the 50 cc and 70 cc models is not guesswork. Surgical teams now use three-dimensional reconstructions of a patient’s preoperative chest CT scans to virtually “test fit” both devices inside the thoracic cavity before ever entering the operating room. In early clinical use of this approach, all patients received the appropriately sized device based on the virtual modeling, and their chest cavities were fully closed after surgery, confirming the simulation’s accuracy.5PubMed. Translation of First North American 50 and 70 cc Total Artificial Heart Virtual and Clinical Implantations: Utility of 3D Computed Tomography to Test Fit Devices Getting the fit right matters: a device that is too large can compress surrounding structures and cause complications, while one that is too small might not deliver enough cardiac output.
Bridge to Transplant Survival
The pivotal trial that led to FDA approval enrolled 81 patients who received the artificial heart and compared them against 35 control patients who met the same entry criteria but were managed without the device. Among device recipients, 79 percent survived to transplantation. Among controls, only 46 percent did.6PubMed. Cardiac replacement with a total artificial heart as a bridge to transplantation That gap made a compelling case, and it remains the cornerstone of the device’s regulatory approval.
Longer single-center reports paint a consistent picture. A recent 20-year review of 196 patients at one institution found that about 39 percent experienced some kind of neurological event during support, and the most common causes of death on the device were multi-organ failure and intracranial hemorrhage.7PubMed Central. Outcomes after SynCardia temporary total artificial heart implantation: A 20‐year single‐center experience in 196 patients – Section: Results A separate 100-patient series reported similar patterns: the most common adverse events during device support were infection, ischemic stroke (at a rate of 4.6 per 100 patient-months), and bleeding requiring intervention. The leading cause of death on device support was multi-organ failure, accounting for over half of deaths.8The Annals of Thoracic Surgery. Experience With SynCardia Total Artificial Heart as a Bridge to Transplantation in 100 Patients – Section: Results These numbers can look sobering, but they need context: the patients receiving a total artificial heart are among the sickest in all of heart failure, often on the verge of death from biventricular collapse when the device is implanted.
What Happens After Transplant
Surviving to transplant is only half the story. How patients fare after receiving a donor heart matters just as much. A large registry analysis comparing outcomes over 15 years found that ten-year survival after transplant was about 53 percent for patients bridged with a total artificial heart, compared with roughly 62 percent for those bridged with a left ventricular assist device and about 63 percent for patients who went directly to transplant without any mechanical bridge. That gap is statistically real but narrows with an important caveat: when researchers looked only at patients who survived the first year after transplant, the long-term survival curves converged. At ten years conditional on one-year survival, all three groups hovered around 67 to 69 percent.9PubMed Central. Heart Transplantation after Total Artificial Heart Bridging – Outcomes Over 15 Years – Section: Results In plain terms, if a TAH-bridged patient makes it through the difficult first year after transplant, their long-term outlook is essentially the same as anyone else’s.
A separate analysis focused on five-year post-transplant mortality told a similar story but with somewhat higher numbers for TAH recipients: about 29 percent mortality at five years, compared with roughly 15 percent for LVAD-bridged patients and 22 percent for those bridged with a biventricular assist device. Yet one-year survival and complication rates were similar across all groups, suggesting the early perioperative period after transplant is the critical window where prior TAH support takes a toll.10PubMed. Heart Transplant Outcomes After Total Artificial Heart
Infection, Bleeding, and Stroke
Because the SynCardia TAH requires drivelines that pass through the skin to connect to an external air driver, infection is essentially unavoidable at some rate. In one cohort of 47 patients supported for more than a year, systemic infections occurred in over half, driveline infections in about a quarter, thromboembolic events in roughly a fifth, and hemorrhagic events in about 14 percent.11ASAIO Journal. Results With Syncardia Total Artificial Heart Beyond 1 Year – Section: Abstract Another group reported that during the first month after implant, bacteremia and driveline infections were each the most common infectious complications, each occurring in about 27 percent of cases.12PubMed. Perioperative Prophylaxis for Total Artificial Heart Transplantation – Section: RESULTS
Stroke is the complication that probably causes the most anxiety. The artificial surfaces inside the device can trigger blood clots, which can travel to the brain. To counter this, patients receive anticoagulation therapy, typically a combination of blood thinners and antiplatelet drugs. One center that used a consistent anticoagulation protocol across 99 consecutive recipients reported an embolic stroke rate of just 0.08 per patient-year after the second postoperative day, in patients free of device infection. There were no spontaneous hemorrhagic strokes. Early postoperative bleeding occurred in about 20 percent of patients, almost entirely within the first week.13PubMed. Results with an anticoagulation protocol in 99 SynCardia total artificial heart recipients A separate experience with over 100 implants found that about 84 percent of patients had no neurological complication of any kind, and among the roughly 8 percent who had embolic strokes, infections were often a contributing factor.14The Journal of Thoracic and Cardiovascular Surgery. Experience with more than 100 total artificial heart implants – Section: Results
Getting anticoagulation right is tricky. Different blood tests used to monitor clotting do not always agree with each other, which complicates management. One study found that when a specific clotting assay was used to guide therapy, the results of the more traditional clotting test fell below the expected target range, though this discrepancy did not lead to additional clotting events.15PubMed Central. Anticoagulation in syncardia total artificial heart recipients: anti-factor Xa or activated partial thromboplastin time? The takeaway for patients and caregivers is that anticoagulation requires frequent monitoring and adjustment, and there is no single “set it and forget it” approach.
Living With the Device at Home
For the first several weeks after implantation, patients are tethered to a large hospital-based driver console. But a portable driver system, the Freedom Driver, can eventually replace that console and allow patients to leave the hospital. In a study of 22 patients at a German center, patients were supported on the hospital driver for an average of 40 days after implantation, then transitioned to the portable driver and maintained in-hospital for another 18 days of training before discharge. Once home, they were supported on the portable driver for an average of about six months, though the range was enormous, from just 2 days to nearly 600 days. All 22 patients were discharged to their own homes rather than to intermediate care facilities, and all were walking independently at discharge.16PubMed Central. Home Discharge and Out-of-Hospital Follow-Up of Total Artificial Heart Patients Supported by a Portable Driver System – Section: Results
Home discharge is a real milestone, but the portable driver is not trouble-free. In a separate single-center series of 11 patients switched to the Freedom Driver, more than half needed to be temporarily returned to the larger hospital console at some point during their support period. Two were later switched back to the portable driver and continued on it until transplant.17PubMed. SynCardia Portable Freedom Driver: A Single-Center Experience With 11 Patients – Section: RESULTS The driver requires batteries, and patients carry a backup unit at all times. Showering, traveling, and daily activities all require planning around the drivelines and equipment. Still, the alternative to the portable driver is indefinite hospitalization, so most patients find the trade-off worthwhile.
Exercise and Physical Limits
Even with the device running well, TAH recipients face genuine physical constraints. Exercise testing reveals that their peak oxygen consumption, a standard measure of aerobic fitness, runs around 36 percent of what would be predicted for healthy individuals their age. The main bottleneck is the pump itself: during exercise, cardiac output increased by only about 9 percent, far less than the doubling or tripling a natural heart can achieve. To compensate, the body extracts more oxygen from each unit of blood than normal, but that strategy has limits.18ASAIO Journal. Exercise Capacity in Patients with the Total Artificial Heart – Section: Abstract Patients can walk, perform household tasks, and manage daily life, but vigorous exercise is out of reach. One patient in Italy famously surpassed 1,000 days on the device with what his physicians described as “excellent exercise capacity” and a good quality of life, suggesting there is real variability in how well patients adapt.19DAIC. Italian Man Surpasses 1,000 Days Of Support With Artificial Heart
Pediatric and Smaller Patients
Total artificial hearts were historically adult-only technology. The development of the 50 cc device changed that, opening the door for adolescents and smaller adults who had previously been limited to biventricular assist devices or, in many cases, had no mechanical support option at all. A review of worldwide pediatric experience with the SynCardia TAH found that 51 children had been supported, 36 with the 70 cc version and 15 with the 50 cc. The most common diagnosis leading to implant was dilated cardiomyopathy, and the average age was about 16. Overall survival was 71 percent, broadly comparable to what adults experience.20PubMed Central. The total artificial heart in pediatrics: outcomes in an evolving field A separate analysis found that at 60, 90, and 120 days after implant, 70, 63, and 58 percent of pediatric patients respectively had positive outcomes, again similar to adult benchmarks.21PubMed. Worldwide Experience with the Syncardia Total Artificial Heart in the Pediatric Population
The trend in recent years has been toward greater use of the smaller device in this population. In the five years leading up to the pediatric review, 79 percent of implants were with the 50 cc TAH. Some of these patients were also transitioned to the portable Freedom Driver, allowing them to leave the hospital, a meaningful quality-of-life improvement for teenagers facing months of waiting for a donor heart.22PubMed Central. The total artificial heart in pediatrics: outcomes in an evolving field
Why Not Just Use a Ventricular Assist Device
A question that comes up naturally is why anyone would need an entire heart replaced when assist devices are more common and less invasive. The answer is that ventricular assist devices, including the widely used LVADs, work by helping a heart that still has some function. They support one ventricle, occasionally both, but they require the native heart to remain in place. For patients with biventricular failure so severe that neither side of the heart contributes meaningful pumping, or for those with structural problems like massive ventricular thrombus, failed grafts from prior surgeries, or certain forms of congenital heart disease, there is no native heart worth assisting. The SynCardia TAH exists for exactly this population: patients who have run out of options short of transplantation and who need both ventricles replaced entirely.
The other scenario where a total artificial heart has an edge involves patients at high risk of right heart failure after LVAD placement. Predicting who will tolerate an LVAD without right-sided collapse is imperfect, and right heart failure after LVAD implant is a major source of morbidity. By removing both ventricles and replacing them, the TAH sidesteps the problem entirely. The trade-off is a bigger operation, external drivelines, and the complication profile described above.
What Comes After SynCardia
The SynCardia TAH has been the only FDA-approved total heart replacement for years, but the technology is evolving. Several next-generation devices are in various stages of development, aiming to address the current device’s biggest limitations. Among the most prominent are continuous-flow total artificial hearts being developed by multiple groups, which replace the pulsatile diaphragm design with spinning rotors that move blood in a steady stream rather than discrete beats. These devices promise smaller size, fewer moving parts, and potentially longer durability.23PubMed. Total artificial heart implantation as a bridge to transplantation: a viable model for the future?
There is also serious interest in using total artificial hearts as permanent therapy rather than as a bridge. Right now, the SynCardia is approved only to keep patients alive until transplant, but donor hearts remain scarce and waiting lists keep growing. A device durable and reliable enough to serve as a permanent implant, sometimes called destination therapy, would dramatically expand the pool of patients who could benefit. Achieving that requires solving problems of long-term biocompatibility, power delivery (ideally without drivelines passing through the skin), and durability measured in years rather than months. Some groups are experimenting with hybrid designs that incorporate biological materials to reduce clotting and infection risk. The current SynCardia, with all its limitations, laid the groundwork for that future by proving that complete heart replacement is survivable and that patients can leave the hospital, go home, and wait for a transplant with a machine doing the entire work of their heart.